modeling_armt.py

# === Inlined ARMT for HF Hub (single-file) ===
# This file contains all ARMT modeling code inlined for easy loading.
# Generated automatically during training checkpoint save.

# ---- act_utils.py ----
from torch import nn
import torch
import numpy as np
import math

from torch.nn import TransformerEncoder, TransformerEncoderLayer


def gen_timing_signal(length, channels, min_timescale=1.0, max_timescale=1.0e4):
    """
    Generates a [1, length, channels] timing signal consisting of sinusoids
    Adapted from:
    https://github.com/tensorflow/tensor2tensor/blob/master/tensor2tensor/layers/common_attention.py
    """
    position = np.arange(length)
    num_timescales = channels // 2
    log_timescale_increment = ( math.log(float(max_timescale) / float(min_timescale)) / (float(num_timescales) - 1))
    inv_timescales = min_timescale * np.exp(np.arange(num_timescales).astype(float) * -log_timescale_increment)
    scaled_time = np.expand_dims(position, 1) * np.expand_dims(inv_timescales, 0)

    signal = np.concatenate([np.sin(scaled_time), np.cos(scaled_time)], axis=1)
    signal = np.pad(signal, [[0, 0], [0, channels % 2]], 
                    'constant', constant_values=[0.0, 0.0])
    signal =  signal.reshape([1, length, channels])

    return torch.from_numpy(signal).type(torch.FloatTensor)

class ACT_basic(nn.Module):
    def __init__(self,hidden_size):
        super(ACT_basic, self).__init__()
        self.sigma = nn.Sigmoid()
        self.p = nn.Linear(hidden_size,1)  
        self.p.bias.data.fill_(1) 
        self.threshold = 1 - 0.1
        self.eps = 0.1

    def forward(self, *args, state, inputs, fn, time_enc, pos_enc, max_hop,  encoder_output=None, **kwargs):
        # init_hdd
        ## [B, S]
        noisy_halting = False
        if 'noisy_halting' in kwargs:
            noisy_halting = kwargs['noisy_halting']
            kwargs.pop('noisy_halting')
        halting_probability = torch.zeros(inputs.shape[0],inputs.shape[1]).cuda()
        ## [B, S]
        remainders = torch.zeros(inputs.shape[0],inputs.shape[1]).cuda()
        ## [B, S]
        n_updates = torch.zeros(inputs.shape[0],inputs.shape[1]).cuda()
        ## [B, S, HDD]
        previous_state = torch.zeros_like(inputs).cuda()
        step = 0
        # for l in range(self.num_layers):
        rest = None

        while( ((halting_probability<self.threshold) & (n_updates < max_hop)).byte().any()):
            # Add timing signal
            # state = state + time_enc[:, :inputs.shape[1], :].type_as(inputs.data)
            # state = state + pos_enc[:, step, :].unsqueeze(1).repeat(1,inputs.shape[1],1).type_as(inputs.data)

            p = self.sigma(self.p(state)).squeeze(-1)
            if noisy_halting and self.training:
                p = p + torch.randn_like(p) * self.eps
            # Mask for inputs which have not halted yet
            still_running = (halting_probability < 1.0).float()

            # Mask of inputs which halted at this step
            new_halted = (halting_probability + p * still_running > self.threshold).float() * still_running

            # Mask of inputs which haven't halted, and didn't halt this step
            still_running = (halting_probability + p * still_running <= self.threshold).float() * still_running

            # Add the halting probability for this step to the halting
            # probabilities for those input which haven't halted yet
            halting_probability = halting_probability + p * still_running

            # Compute remainders for the inputs which halted at this step
            remainders = remainders + new_halted * (1 - halting_probability)

            # Add the remainders to those inputs which halted at this step
            halting_probability = halting_probability + new_halted * remainders

            # Increment n_updates for all inputs which are still running
            n_updates = n_updates + still_running + new_halted

            # Compute the weight to be applied to the new state and output
            # 0 when the input has already halted
            # p when the input hasn't halted yet
            # the remainders when it halted this step
            update_weights = p * still_running + new_halted * remainders

            if(encoder_output):
                state, _ = fn((state,encoder_output))
            else:
                # apply transformation on the state
                state = fn(state, *args, **kwargs)
                if isinstance(state, tuple):
                    rest = state[1:]
                    state = state[0]

            # update running part in the weighted state and keep the rest
            previous_state = ((state * update_weights.unsqueeze(-1)) + (previous_state * (1 - update_weights.unsqueeze(-1))))
            ## previous_state is actually the new_state at end of hte loop 
            ## to save a line I assigned to previous_state so in the next 
            ## iteration is correct. Notice that indeed we return previous_state
            step+=1
        if rest is None:
            return previous_state, (remainders,n_updates)
        else:
            return (previous_state, *rest), (remainders, n_updates)


class ACT_constant_depth():
    def __init__(self):
        super(ACT_constant_depth, self).__init__()

    def __call__(self, *args, state, inputs, fn, time_enc, pos_enc, max_hop,  encoder_output=None, **kwargs):
        # init_hdd
        ## [B, S]
        remainders = torch.zeros(inputs.shape[0],inputs.shape[1]).cuda()
        ## [B, S]
        n_updates = torch.zeros(inputs.shape[0],inputs.shape[1]).cuda()
        ## [B, S, HDD]
        previous_state = torch.zeros_like(inputs).cuda()
        step = 0
        # for l in range(self.num_layers):
        rest = None

        
        while(step < max_hop):
            print('constsant depth TRUE')
            # Add timing signal
            # state = state + time_enc[:, :inputs.shape[1], :].type_as(inputs.data)
            # state = state + pos_enc[:, step, :].unsqueeze(1).repeat(1,inputs.shape[1],1).type_as(inputs.data)

            if(encoder_output):
                state, _ = fn((state,encoder_output))
            else:
                # apply transformation on the state
                state = fn(state, *args, **kwargs)
                if isinstance(state, tuple):
                    rest = state[1:]
                    state = state[0]
            
            # update running part in the weighted state and keep the rest
            # print(state.shape, previous_state.shape, update_weights.shape)
            # print(state.dtype, previous_state.dtype, update_weights.dtype)
            previous_state = state
            ## previous_state is actually the new_state at end of hte loop 
            ## to save a line I assigned to previous_state so in the next 
            ## iteration is correct. Notice that indeed we return previous_state
            step+=1
        if rest is None:
            return previous_state, (remainders,n_updates)
        else:
            return (previous_state, *rest), (remainders, n_updates)

class ACTForWholeARMT(nn.Module):
    def __init__(self,hidden_size):
        super(ACTForWholeARMT, self).__init__()
        self.sigma = nn.Sigmoid()
        self.p = nn.Linear(hidden_size,1)  
        self.p.bias.data.fill_(1) 
        self.threshold = 1 - 0.1

    def forward(self, *args, state, inputs, fn_no_update, fn_update, time_enc, pos_enc, max_hop,  encoder_output=None, **kwargs):
        # init_hdd
        ## [B, S]

        halting_probability = torch.zeros(inputs.shape[0],inputs.shape[1]).cuda()
        ## [B, S]
        remainders = torch.zeros(inputs.shape[0],inputs.shape[1]).cuda()
        ## [B, S]
        n_updates = torch.zeros(inputs.shape[0],inputs.shape[1]).cuda()
        ## [B, S, HDD]
        previous_state = torch.zeros_like(inputs).cuda()
        step = 0
        # for l in range(self.num_layers):
        rest = None
        while( ((halting_probability < self.threshold) & (n_updates < max_hop)).byte().any()):
            # Add timing signal
            # state = state + time_enc[:, :inputs.shape[1], :].type_as(inputs.data)
            # state = state + pos_enc[:, step, :].unsqueeze(1).repeat(1,inputs.shape[1],1).type_as(inputs.data)

            p = self.sigma(self.p(state)).squeeze(-1)
            # Mask for inputs which have not halted yet
            still_running = (halting_probability < 1.0).float()

            # Mask of inputs which halted at this step
            new_halted = (halting_probability + p * still_running > self.threshold).float() * still_running

            # Mask of inputs which haven't halted, and didn't halt this step
            still_running = (halting_probability + p * still_running <= self.threshold).float() * still_running

            # Add the halting probability for this step to the halting
            # probabilities for those input which haven't halted yet
            halting_probability = halting_probability + p * still_running

            # Compute remainders for the inputs which halted at this step
            remainders = remainders + new_halted * (1 - halting_probability)

            # Add the remainders to those inputs which halted at this step
            halting_probability = halting_probability + new_halted * remainders

            # Increment n_updates for all inputs which are still running
            n_updates = n_updates + still_running + new_halted

            # Compute the weight to be applied to the new state and output
            # 0 when the input has already halted
            # p when the input hasn't halted yet
            # the remainders when it halted this step
            update_weights = p * still_running + new_halted * remainders

            if(encoder_output):
                if ((halting_probability<self.threshold) & (n_updates < max_hop)).byte().any():
                    state, _ = fn_no_update((state,encoder_output))
                else:
                    state, _ = fn_update((state, encoder_output))
            else:
                # apply transformation on the state
                if ((halting_probability<self.threshold) & (n_updates < max_hop)).byte().any():
                    state = fn_no_update(state, *args, **kwargs)
                else:
                    state = fn_update(state, *args, **kwargs)
                if isinstance(state, tuple):
                    rest = state[1:]
                    state = state[0]

            # update running part in the weighted state and keep the rest
            previous_state = ((state * update_weights.unsqueeze(-1)) + (previous_state * (1 - update_weights.unsqueeze(-1))))
            ## previous_state is actually the new_state at end of hte loop 
            ## to save a line I assigned to previous_state so in the next 
            ## iteration is correct. Notice that indeed we return previous_state
            step+=1
        if rest is None:
            return previous_state, (remainders,n_updates)
        else:
            return (previous_state, *rest), (remainders, n_updates)

class ACTForWholeARMT_constant_depth():
    def __init__(self):
        super(ACTForWholeARMT_constant_depth, self).__init__()


    def __call__(self, *args, state, inputs, fn_no_update, fn_update, time_enc, pos_enc, max_hop,  encoder_output=None, **kwargs):
        print("\n\n\n\n\n\n\n\n\n\nCONSTANT DEPTH TRUE")
        # init_hdd
        ## [B, S]
        remainders = torch.zeros(inputs.shape[0],inputs.shape[1]).cuda()
        ## [B, S]
        n_updates = torch.full((inputs.shape[0],inputs.shape[1]), max_hop).cuda()
        ## [B, S, HDD]
        previous_state = torch.zeros_like(inputs).cuda()
        step = 0
        # for l in range(self.num_layers):
        rest = None
        while(step < max_hop):
            # Add timing signal
            # state = state + time_enc[:, :inputs.shape[1], :].type_as(inputs.data)
            # state = state + pos_enc[:, step, :].unsqueeze(1).repeat(1,inputs.shape[1],1).type_as(inputs.data)
            if(encoder_output):
                if (step < max_hop):
                    state, _ = fn_no_update((state,encoder_output))
                else:
                    state, _ = fn_update((state, encoder_output))
            else:
                # apply transformation on the state
                if (step < max_hop):
                    state = fn_no_update(state, *args, **kwargs)
                else:
                    state = fn_update(state, *args, **kwargs)
                if isinstance(state, tuple):
                    rest = state[1:]
                    state = state[0]

            # update running part in the weighted state and keep the rest
            previous_state = state
            ## previous_state is actually the new_state at end of hte loop 
            ## to save a line I assigned to previous_state so in the next 
            ## iteration is correct. Notice that indeed we return previous_state
            step+=1
        if rest is None:
            return previous_state, (remainders,n_updates)
        else:
            return (previous_state, *rest), (remainders, n_updates)


class ACT_transformer(nn.Module):
    def __init__(self, hidden_size, num_heads=4, num_transformer_layers=1, dropout=0.1):
        super(ACT_transformer, self).__init__()
        # Transformer encoder
        transformer_layer = TransformerEncoderLayer(
            d_model=hidden_size,
            nhead=num_heads,
            dim_feedforward=hidden_size,
            dropout=dropout,
            norm_first=True
        )
        self.transformer = TransformerEncoder(transformer_layer, 
                                              num_layers=num_transformer_layers)
        
        # Feedforward layer for logits
        self.logit_ff = nn.Linear(hidden_size, 1)  
        self.logit_ff.bias.data.fill_(1)
        
        # Halting threshold
        self.sigma = nn.Sigmoid()
        self.threshold = 1 - 0.1

    def generate_causal_mask(self, seq_len):
        mask = torch.triu(torch.ones(seq_len, seq_len), diagonal=1)
        mask = mask.masked_fill(mask == 1, float('-inf'))
        return mask

    def forward(self, *args, state, inputs, fn, time_enc, pos_enc, max_hop, encoder_output=None, **kwargs):
        batch_size, seq_len, hidden_size = inputs.shape
        halting_probability = torch.zeros(batch_size, seq_len).cuda()
        remainders = torch.zeros(batch_size, seq_len).cuda()
        n_updates = torch.zeros(batch_size, seq_len).cuda()
        previous_state = torch.zeros_like(inputs).cuda()
        step = 0
        rest = None

        causal_mask = self.generate_causal_mask(seq_len).cuda()

        while ((halting_probability < self.threshold) & (n_updates < max_hop)).byte().any():
            state_transformed = self.transformer(
                state.permute(1, 0, 2),  # [S, B, H]
                mask=causal_mask
            )  # [S, B, H]
            state_transformed = state_transformed.permute(1, 0, 2)  # [B, S, H]

            # Pass through linear layer and sigmoid
            p = self.sigma(self.logit_ff(state_transformed)).squeeze(-1)  # [B, S]

            # Update halting logic
            still_running = (halting_probability < 1.0).float()
            new_halted = (halting_probability + p * still_running > self.threshold).float() * still_running
            still_running = (halting_probability + p * still_running <= self.threshold).float() * still_running
            halting_probability = halting_probability + p * still_running
            remainders = remainders + new_halted * (1 - halting_probability)
            halting_probability = halting_probability + new_halted * remainders
            n_updates = n_updates + still_running + new_halted
            update_weights = p * still_running + new_halted * remainders

            if encoder_output is not None:
                state, _ = fn((state, encoder_output))
            else:
                state = fn(state, *args, **kwargs)
                if isinstance(state, tuple):
                    rest = state[1:]
                    state = state[0]

            previous_state = (
                (state * update_weights.unsqueeze(-1)) +
                (previous_state * (1 - update_weights.unsqueeze(-1)))
            )
            step += 1

        if rest is None:
            return previous_state, (remainders, n_updates)
        else:
            return (previous_state, *rest), (remainders, n_updates)


# ---- language_modeling.py ----
import math
import torch
from torch.nn import CrossEntropyLoss
from transformers.modeling_outputs import CausalLMOutputWithCrossAttentions
from transformers.cache_utils import Cache, DynamicCache
from torch.nn.functional import relu as r
import torch.nn.functional as F
import os
from dataclasses import dataclass
from transformers.modeling_outputs import ModelOutput

@dataclass
class ARMTOutput(ModelOutput):
    """
    Custom output format for ARMT with all necessary fields.
    This replaces Munch in the original implementation.
    """
    logits: torch.FloatTensor = None
    loss: torch.FloatTensor = None
    hidden_states: torch.FloatTensor = None
    attentions: tuple = None
    past_key_values: tuple = None
    remainders: torch.FloatTensor = None
    n_updates: torch.FloatTensor = None
    ce_loss: torch.FloatTensor = None

# Import optimized cross-entropy loss
try:
    from cut_cross_entropy import linear_cross_entropy
    CUT_CROSS_ENTROPY_AVAILABLE = True
except ImportError:
    CUT_CROSS_ENTROPY_AVAILABLE = False
    print("Warning: cut_cross_entropy not available, falling back to standard CrossEntropyLoss")

# inlined act_utils: removed import ACT_basic, gen_timing_signal, ACTForWholeARMT, ACT_transformer, ACT_constant_depth, ACTForWholeARMT_constant_depth
try:
    from baselines.rwkv.language_modeling import RWKVModel
    RWKV_imported = True
except ImportError:
    print("*** Can't import RWKV model ***")
    RWKV_imported = False
def dpfp(x, nu=1):
  x = torch.cat([r(x), r(-x)], dim=-1)
  x_rolled = torch.cat([x.roll(shifts=j, dims=-1)
           for j in range(1,nu+1)], dim=-1)
  x_repeat = torch.cat([x] * nu, dim=-1)
  return x_repeat * x_rolled

class DPFP:
    def __init__(self, nu):
        self.nu = nu
    
    def __call__(self, x):
        nu = self.nu
        x = torch.cat([r(x), r(-x)], dim=-1)
        x_rolled = torch.cat([x.roll(shifts=j, dims=-1) for j in range(1,nu+1)], dim=-1)
        x_repeat = torch.cat([x] * nu, dim=-1)
        return x_repeat * x_rolled
def attn_mask_to_4d(attn_mask, upper, query_len):
    if attn_mask is None:
        return None
    seg_len = attn_mask.size(-1)
    if upper:
        tri = torch.triu(torch.ones(query_len, seg_len, dtype=attn_mask.dtype, device=attn_mask.device))
    else:
        tri = torch.tril(torch.ones(query_len, seg_len, dtype=attn_mask.dtype, device=attn_mask.device))

    mask = torch.einsum('bj,ij->bij', attn_mask, tri)
    mask = mask.unsqueeze(1)
    return mask

def invert_attn_mask(attn_mask, dtype):
        min_dtype = torch.finfo(dtype).min
        # Use the same dtype as attn_mask to avoid dtype conversion
        one = torch.tensor(1.0, dtype=attn_mask.dtype, device=attn_mask.device)
        new_mask = (one - attn_mask) * min_dtype
        return new_mask



class AssociativeLayerWrapper(torch.nn.Module):

    def __init__(self, layer, d_model,  num_mem_tokens, d_mem, n_heads=1, correction=True, info=None, use_denom=True, gating=False) -> None:
        super().__init__()
        self.info = info
        self.seg_num = 0
        self.d_model = d_model
        self.num_mem_tokens = num_mem_tokens
        self.d_mem = d_mem
        self.n_heads = n_heads
        self.gating = gating
        nu = 3
        self.d_key = 2 * nu * d_mem

        assert self.d_mem % n_heads == 0 and self.d_model % n_heads == 0

        self.phi = DPFP(nu)
        # self.d_key = d_mem
        # self.phi = torch.nn.Identity()

        self.use_denom = use_denom

        # Get the proper dtype from the layer
        layer_dtype = next(layer.parameters()).dtype
        
        self.W_mq = torch.nn.Linear(d_model, d_mem, bias=False, dtype=layer_dtype)
        # torch.nn.init.zeros_(self.W_mq.weight)
        self.W_mk = torch.nn.Linear(d_model, d_mem, bias=False, dtype=layer_dtype)
        self.W_mv = torch.nn.Linear(d_model, d_model, bias=False, dtype=layer_dtype)
        if gating:
            self.W_mb = torch.nn.Linear(d_model, d_model, dtype=layer_dtype)
        else:
            self.W_mb = torch.nn.Linear(d_model, n_heads, dtype=layer_dtype)
        torch.nn.init.zeros_(self.W_mv.weight)
        s = 1/math.sqrt(d_model)
        # torch.nn.init.uniform_(self.W_mq.weight, -s, s)
        # torch.nn.init.uniform_(self.W_mk.weight, -s, s)
        # torch.nn.init.uniform_(self.W_mb.weight, -s, s)


        # self.ln = torch.nn.LayerNorm(d_model)

        self.layer = layer
        
        self.generate_mode = False
        self.first_seg = True
        self.correction = correction
        
        self.zero_mem()

    def _to_heads(self, x):
        bsz, seq_len, d_model = x.shape
        x = x.reshape(bsz, seq_len, self.n_heads, d_model // self.n_heads)
        x = x.permute(0, 2, 1, 3)
        return x
    
    def _from_heads(self, x):
        bsz, n_heads, seq_len, d_head = x.shape
        x = x.permute(0, 2, 1, 3).reshape(bsz, seq_len, n_heads * d_head)
        return x
    def associate(self, hidden_states):
        bsz, seq_len, d_model = hidden_states.shape

        self.W_mem = self.W_mem.to(hidden_states.device)
        if self.use_denom:
            self.z = self.z.to(hidden_states.device)

        q = self._to_heads(self.W_mq(hidden_states))
        mq = self.phi(q) # (bsz, n_heads, seq_len, 2 * d_head * nu)
        mq = F.normalize(mq, dim=-1, p=2.0)
        # crutch for dataparallel
        # mq += 0 * self.W_mb(hidden_states).sum() * self.W_mk(hidden_states).sum() * self.W_mv(hidden_states).sum()
        num = torch.einsum('ihjk,ihkt->ihjt', mq, self.W_mem)
        if self.use_denom:
            denom = torch.einsum("ihk,ihjk->ihj", self.z, mq)[..., None] + 1e-5
            hidden_states = num / denom # (bsz, n_heads, seq_len, d_model // n_heads)
        else:
            hidden_states = num
        hidden_states = self._from_heads(hidden_states)
        return hidden_states
    
    def forward(self, hidden_states, *args, **kwargs):
        if not self.first_seg:
            hidden_states = self.associate(
                # self.ln(
                    hidden_states
                # )
            ) + hidden_states
        out = self.layer(hidden_states, *args, **kwargs)
        if not self.generate_mode:
            # The layer output contains hidden states, not logits
            # For transformer layers, the output is typically the hidden states
            if isinstance(out, tuple):
                mem_tokens = out[0][:, -self.num_mem_tokens:]
            else:
                mem_tokens = out[:, -self.num_mem_tokens:]

            self.update_mem(mem_tokens)
        return out
    
    def forward_no_update(self, hidden_states, *args, **kwargs):
        if not self.first_seg:
            hidden_states = self.associate(
                # self.ln(
                    hidden_states
                # )
            )+ hidden_states
        out = self.layer(hidden_states, *args, **kwargs)
        return out
    
    def forward_no_update(self, hidden_states, *args, **kwargs):
        if not self.first_seg:
            hidden_states = self.associate(
                # self.ln(
                    hidden_states
                # )
            ) + hidden_states
        out = self.layer(hidden_states, *args, **kwargs)
        return out

    def update_mem(self, mem_tokens):

        self.W_mem = self.W_mem.to(mem_tokens.device)
        if self.use_denom:
            self.z = self.z.to(mem_tokens.device)
        k = self._to_heads(self.W_mk(mem_tokens))
        mk = self.phi(k)
        mk = F.normalize(mk, dim=-1, p=2.0)

        new_mv = self._to_heads(self.W_mv(mem_tokens)) # (bsz, n_heads, num_mem_tokens, d_model)
        if not self.first_seg:
            num = torch.einsum('ihjk,ihkt->ihjt', mk, self.W_mem)
            if self.use_denom:
                denom = torch.einsum("ihj,ihkj->ihk", self.z, mk)[..., None] + 1e-5
                prev_mv = num / denom
                if self.correction:
                    new_info_coef = (1 - denom / (torch.linalg.norm(mk, dim=-1) ** 2)[..., None])
                    new_info_coef = torch.clip(new_info_coef, 0, 1).detach()
                else:
                    new_info_coef = 1
            else:
                prev_mv = num
        else: 
            prev_mv = torch.zeros_like(new_mv, device=new_mv.device)
            new_info_coef = 1
        
        mv = new_mv - prev_mv

        # new_norm = torch.linalg.norm(new_mv, dim=-1)
        # old_norm = torch.linalg.norm(prev_mv, dim=-1)
        # new_info_coef = torch.clip(1 - old_norm / (new_norm + 1e-5), -10, 10)[..., None].detach()
        # new_info_coef = 1 - denom

        mb = self._to_heads(torch.sigmoid(self.W_mb(mem_tokens)))

        einop = f"ihjk,ihjt,ihj{'t' if self.gating else 'x'}->ihkt"
        associations =  torch.einsum(einop, mk, mv, mb) # (bsz, n_heads, d_mem, d_model)

        self.W_mem = self.W_mem + associations

        if self.use_denom:
            self.z = self.z + (new_info_coef*mk).sum(dim=-2)
        # self.z = self.z + (new_info_coef*mb[..., None]*mk).sum(dim=1)
        self.seg_num += 1
        self.first_seg = False

    def freeze_mem(self):
        self.W_mb.weight.requires_grad = False
        self.W_mb.bias.requires_grad = False
        self.W_mq.weight.requires_grad = False
        self.W_mk.weight.requires_grad = False
        self.W_mv.weight.requires_grad = False

    def zero_mem(self):
        self.first_seg = True
        # Get the proper dtype from the layer parameters
        layer_dtype = next(self.layer.parameters()).dtype
        self.W_mem = torch.zeros(1, self.n_heads, self.d_key // self.n_heads, self.d_model // self.n_heads, dtype=layer_dtype)
        self.W_mem.requires_grad_(False)
        if self.use_denom:
            self.z = torch.zeros(1, self.n_heads, self.d_key // self.n_heads, dtype=layer_dtype)
            self.z.requires_grad_(False)
        self.seg_num = 0

    def detach_mem(self):
        self.W_mem = self.W_mem.detach()
        if self.use_denom:
            self.z = self.z.detach()




class AdaptiveAssociativeLayerWrapper(AssociativeLayerWrapper):
    def __init__(self, 
                 layer, 
                 d_model, 
                 num_mem_tokens, 
                 d_mem, 
                 max_hop,
                 n_heads=1, 
                 correction=True, 
                 info=None, 
                 use_denom=True, 
                 gating=False,
                 constant_depth=False,
                 
                ) -> None:
        super().__init__(layer, d_model, num_mem_tokens, d_mem, n_heads, correction, info, use_denom, gating)
        self.act = ACT_basic(d_model) if not constant_depth else ACT_constant_depth()
        self.depth = max_hop
        self.max_length = 1024

        self.timing_signal = gen_timing_signal(self.max_length, d_model)
        ## for t
        self.position_signal = gen_timing_signal(self.depth, d_model)

        self.remainders = torch.zeros(1,)
        self.n_updates = torch.zeros(1,)
        self.segments_passed = torch.zeros(1,)

    def associate(self, hidden_states):
        self.remainders = self.remainders.to(hidden_states.device)
        self.n_updates = self.n_updates.to(hidden_states.device)
        self.segments_passed = self.segments_passed.to(hidden_states.device)
        out, (remainders, n_updates) = self.act(
            state=hidden_states, 
            inputs=hidden_states, 
            fn=super().associate,
            time_enc=self.timing_signal,
            pos_enc=self.position_signal,
            max_hop=self.depth
        )
        
        self.remainders = self.remainders + remainders.mean() # 1 - \sum(h_i); L' = L + tau * mean(remainders)
        self.n_updates = self.n_updates + n_updates.mean()
        self.segments_passed = self.segments_passed + 1
        return out
    
    def zero_mem(self):
        self.remainders = torch.zeros(1,)
        self.n_updates = torch.zeros(1,)
        self.segments_passed = torch.zeros(1,)
        return super().zero_mem()
    
    def detach_mem(self):
        self.remainders = torch.zeros(1,)
        self.n_updates = torch.zeros(1,)
        self.segments_passed = torch.zeros(1,)
        return super().detach_mem()



class AdaptiveAssociativeLayerWrapper2(AssociativeLayerWrapper):
    def __init__(self, 
                 layer, 
                 d_model, 
                 num_mem_tokens, 
                 d_mem, 
                 max_hop,
                 n_heads=1, 
                 correction=True, 
                 info=None, 
                 use_denom=True, 
                 gating=False,
                 act_format='linear',
                 noisy_halting=False,
                 constant_depth=False,
                ) -> None:
        super().__init__(layer, d_model, num_mem_tokens, d_mem, n_heads, correction, info, use_denom, gating)

        if act_format=='transformer':
            self.act = ACT_transformer(d_model)
        elif constant_depth:
            self.act = ACT_constant_depth()
        elif act_format == 'linear':
            self.act =  ACT_basic(d_model)
        else:
            raise NotImplemetedError

        self.depth = max_hop
        self.max_length = 1024

        self.noisy_halting = noisy_halting

        self.timing_signal = gen_timing_signal(self.max_length, d_model)
        ## for t
        self.position_signal = gen_timing_signal(self.depth, d_model)

        self.remainders = torch.zeros(1,)
        self.n_updates = torch.zeros(1,)
        self.segments_passed = torch.zeros(1,)

    def forward(self, hidden_states, *args, **kwargs):
        self.remainders = self.remainders.to(hidden_states.device)
        self.n_updates = self.n_updates.to(hidden_states.device)
        self.segments_passed = self.segments_passed.to(hidden_states.device)

        if self.noisy_halting:
            kwargs['noisy_halting'] = self.noisy_halting
        fwd = super().forward_no_update
        out, (remainders, n_updates) = self.act(
            *args,
            state=hidden_states, 
            inputs=hidden_states, 
            fn=fwd,
            time_enc=self.timing_signal,
            pos_enc=self.position_signal,
            max_hop=self.depth,
            **kwargs
        )
        if not self.generate_mode:
            mem_tokens = out[0][:, -self.num_mem_tokens:]
            # mem_tokens = out[0]
            self.update_mem(mem_tokens)
            self.first_seg = False
        self.remainders = self.remainders + remainders.mean() # 1 - \sum(h_i); L' = L + tau * mean(remainders)
        self.n_updates = self.n_updates + n_updates.mean()
        self.segments_passed = self.segments_passed + 1
        return out

    
    def zero_mem(self):
        self.remainders = torch.zeros(1,)
        self.n_updates = torch.zeros(1,)
        self.segments_passed = torch.zeros(1,)
        return super().zero_mem()
    
    def detach_mem(self):
        self.remainders = torch.zeros(1,)
        self.n_updates = torch.zeros(1,)
        self.segments_passed = torch.zeros(1,)
        return super().detach_mem()


class AdaptiveAssociativeLayerWrapper(AssociativeLayerWrapper):
    def __init__(self, 
                 layer, 
                 d_model, 
                 num_mem_tokens, 
                 d_mem, 
                 max_hop,
                 n_heads=1, 
                 correction=True, 
                 info=None, 
                 use_denom=True, 
                 gating=False,
                 
                ) -> None:
        super().__init__(layer, d_model, num_mem_tokens, d_mem, n_heads, correction, info, use_denom, gating)
        self.act = ACT_basic(d_model)
        self.depth = max_hop
        self.max_length = 1024

        self.timing_signal = gen_timing_signal(self.max_length, d_model)
        ## for t
        self.position_signal = gen_timing_signal(self.depth, d_model)

        self.remainders = torch.zeros(1,)
        self.n_updates = torch.zeros(1,)
        self.segments_passed = torch.zeros(1,)

    def associate(self, hidden_states):
        self.remainders = self.remainders.to(hidden_states.device)
        self.n_updates = self.n_updates.to(hidden_states.device)
        self.segments_passed = self.segments_passed.to(hidden_states.device)
        out, (remainders, n_updates) = self.act(
            state=hidden_states, 
            inputs=hidden_states, 
            fn=super().associate,
            time_enc=self.timing_signal,
            pos_enc=self.position_signal,
            max_hop=self.depth
        )
        
        self.remainders = self.remainders + remainders # 1 - \sum(h_i); L' = L + tau * mean(remainders)
        self.n_updates = self.n_updates + n_updates
        self.segments_passed = self.segments_passed + 1
        return out
    
    def zero_mem(self):
        self.remainders = torch.zeros(1,)
        self.n_updates = torch.zeros(1,)
        self.segments_passed = torch.zeros(1,)
        return super().zero_mem()
    


class AssociativeMemoryCell(torch.nn.Module):
    def __init__(self, 
                 base_model, 
                 num_mem_tokens, 
                 d_mem,
                 layers_attr: str = 'model.layers', 
                 wrap_pos=False, 
                 correction=True, 
                 n_heads=1, 
                 use_denom=True, 
                 gating=False, 
                 freeze_mem=False,
                 act_on=False,
                 max_hop=4,
                 act_type='layer',
                 act_format='linear',
                 noisy_halting=False,
                 constant_depth=False,
                 attend_to_previous_input=False,
                 use_sink=False,
                 **rmt_config
        ):
        super().__init__()
        self.model = base_model
        
        self.attend_to_previous_input = attend_to_previous_input
        self.previous_input = None
        self.use_sink = use_sink
        
        self.RWKV_ARMT = isinstance(self.model, RWKVModel) if RWKV_imported else False

        self.num_mem_tokens = num_mem_tokens
        self.d_mem = d_mem
        self.d_model = base_model.get_input_embeddings().embedding_dim
        self.W_mem = []

        self.constant_depth = constant_depth

        self.layers_attrs = layers_attr.split('.')

        def _get_layers_from_model(model_root):
            layers_obj = model_root
            for attr in self.layers_attrs:
                layers_obj = getattr(layers_obj, attr)
            return layers_obj

        layers = _get_layers_from_model(self.model)
        
        for i in range(len(layers)):
            kw = dict(
                layer=layers[i], 
                d_model=self.d_model, 
                num_mem_tokens=self.num_mem_tokens, 
                d_mem=self.d_mem,
                correction=correction,
                info={'layer': i},
                n_heads=n_heads,
                use_denom=use_denom,
                gating=gating,
            )
            if act_on and act_type != 'model':
                kw['act_format'] = act_format
            if act_on and act_type == 'model' and act_format != 'linear':
                raise NotImplementedError
            if act_on and (act_type != 'model'):
                kw['max_hop'] = max_hop
                kw['constant_depth'] = self.constant_depth
                kw['act_format'] = act_format
            if act_on and noisy_halting:
                kw['noisy_halting'] = noisy_halting
            if not act_on:
                layers[i] = AssociativeLayerWrapper(**kw)
            elif act_type == 'associative':
                layers[i] = AdaptiveAssociativeLayerWrapper(**kw)
            elif act_type == 'layer':
                layers[i] = AdaptiveAssociativeLayerWrapper2(**kw)
            elif act_type == 'model':
                layers[i] = AssociativeLayerWrapper(**kw)
            else:
                raise f'Unknown ACT type: {act_type}'

        if act_type == 'model':
            self.act = ACTForWholeARMT(self.d_model) if not self.constant_depth else ACTForWholeARMT_constant_depth()
            self.depth = max_hop
            self.max_length = 1024
            self.timing_signal = gen_timing_signal(self.max_length, self.d_model)
            self.position_signal = gen_timing_signal(self.depth, self.d_model)
        self.act_type = act_type

        self.create_memory(num_mem_tokens)
        self.wrap_pos = wrap_pos
        self.act_on = act_on
        if wrap_pos:
            self.wrap_positional_embeddings(num_mem_tokens)
        
        if freeze_mem:
            for layer in _get_layers_from_model(self.model):
                layer.freeze_mem()

        # Expose a resolver without registering layers as a submodule to avoid shared tensor aliases
        self.get_layers = lambda: _get_layers_from_model(self.model)
    
    def generate_mode(self, is_on):
        for layer in self.get_layers():
            layer.generate_mode = is_on
    
    def create_memory(self, num_mem_tokens):
        self.num_mem_tokens = num_mem_tokens
        embeddings = self.model.get_input_embeddings()
        memory_dim =  getattr(self.model.config, 'n_embd', self.model.config.hidden_size)
        memory_weights = torch.randn((num_mem_tokens, memory_dim), device=embeddings.weight.data.device, dtype=embeddings.weight.data.dtype) * embeddings.weight.data.std()

        self.register_parameter('memory', torch.nn.Parameter(memory_weights, requires_grad=True))
        if self.use_sink:
            self.sink = torch.nn.Parameter(torch.randn((1, memory_dim), device=embeddings.weight.data.device, dtype=embeddings.weight.data.dtype), requires_grad=True)


    def wrap_positional_embeddings(self, num_mem_tokens):
        num_pos_embs, emb_dim = self.model.transformer.wpe.weight.shape
        prev_embs = self.model.transformer.wpe.weight.detach()
        self.model.transformer.wpe = torch.nn.Embedding(num_mem_tokens + num_pos_embs, emb_dim)

        new_num_pos = num_pos_embs + num_mem_tokens
        with torch.no_grad():
            self.model.transformer.wpe.weight[:len(self.model.transformer.wpe.weight)-num_mem_tokens] = prev_embs
        for layer in self.model.transformer.h:
            layer.layer.attn.bias = torch.tril(torch.ones((new_num_pos, new_num_pos), dtype=torch.uint8)).view(
                1, 1, new_num_pos, new_num_pos
            )

    def set_memory(self, input_shape):
        memory = self.memory.repeat(input_shape[0], 1, 1)
        if self.use_sink:
            sink = self.sink.repeat(input_shape[0], 1, 1)
        else:
            sink = None
        return memory, sink

    def zero_mem(self):
        for layer in self.get_layers():
            layer.zero_mem()
        self.previous_input = None
    
    def detach_mem(self):
        for layer in self.get_layers():
            layer.detach_mem()
            pass

    def forward(self, input_ids, labels=None, labels_mask=None, zero_mem=False, attention_mask=None, **kwargs):
        if self.act_type != 'model':
            out = self.forward_with_update(input_ids, labels, labels_mask, zero_mem, attention_mask=attention_mask, **kwargs)
        else:
            seg_kwargs = self.process_input(input_ids=input_ids, 
                                            labels=labels, 
                                            labels_mask=labels_mask, 
                                            zero_mem=zero_mem, 
                                            attention_mask=attention_mask, 
                                            **kwargs
                                        )
            out = self.gptneox_forward_act(**seg_kwargs)
            out = self.process_output(out, labels=labels, labels_mask=labels_mask)
        return out

    def forward_with_update(self, input_ids, labels=None, labels_mask=None, zero_mem=False, **kwargs):
        current_input_ids = input_ids.clone()
        if self.attend_to_previous_input and self.previous_input is not None:
            input_ids = torch.cat([self.previous_input, input_ids], dim=1)
        
        if zero_mem:
            self.zero_mem()

        seg_kwargs = self.process_input(input_ids, **kwargs)
        
        layers = self.get_layers()
        if self.RWKV_ARMT and not layers[0].generate_mode:
            input1 = dict()
            input2 = dict()
            for item in seg_kwargs:
                if isinstance(seg_kwargs[item], torch.Tensor):
                # if False:
                    input1[item] = seg_kwargs[item][:, :-self.num_mem_tokens]
                    input2[item] = seg_kwargs[item][:, -self.num_mem_tokens:]
                else:
                    input1[item] = seg_kwargs[item]
                    input2[item] = seg_kwargs[item]
            
            self.generate_mode(True)
            out = self.model(**input1)
            self.generate_mode(False)
            state_tmp = tuple([torch.clone(state) for state in out['state']])
            out = ARMTOutput(**{k: torch.clone(t) if isinstance(t, torch.Tensor) else t for k, t in out.items()})
            input2['state'] = out['state']
            _ = self.model(**input2)
            out['state'] = state_tmp
            # out['state'] = out2['state']
            # out = self.model(**seg_kwargs)
            # out['logits'] = out['logits'][:, :-self.num_mem_tokens]
        else:
            out = self.model(**seg_kwargs)

        if self.attend_to_previous_input and self.previous_input is not None:
            out['logits'] = out['logits'][:, self.previous_input.size(1):]
        out = self.process_output(out, labels, labels_mask, **kwargs)
        self.previous_input = current_input_ids
        return out

    def process_input(self, input_ids, **kwargs):
        memory_state, sink = self.set_memory(input_ids.shape)
        seg_kwargs = dict(**kwargs)
        inputs_embeds = kwargs.get('inputs_embeds')
        if inputs_embeds is None:
            inputs_embeds = self.model.get_input_embeddings()(input_ids)
        if self.use_sink:
            inputs_embeds = torch.cat([sink, inputs_embeds, memory_state], dim=1)
        else:
            inputs_embeds = torch.cat([inputs_embeds, memory_state], dim=1)
        
        seg_kwargs['input_ids'] = None
        seg_kwargs['inputs_embeds'] = inputs_embeds
        if kwargs.get('attention_mask') is not None:
            seg_kwargs['attention_mask'] = self.pad_attention_mask(kwargs['attention_mask'], dtype=inputs_embeds.dtype)
            if kwargs.get('prev_attn_mask') is not None:
                prev_seg_attn_mask = self.pad_prev_seg_attn_mask(kwargs['prev_attn_mask'], dtype=inputs_embeds.dtype)
                seg_kwargs['attention_mask'] = torch.cat([prev_seg_attn_mask, seg_kwargs['attention_mask']], dim=-1)
        if 'prev_attn_mask' in seg_kwargs:
            seg_kwargs.pop('prev_attn_mask')
        seg_kwargs['output_hidden_states'] = True

        if self.wrap_pos:
            num_pos_embs = self.model.transformer.wpe.weight.shape[0]
            ordinary_pos = torch.arange(0, input_ids.size(1), dtype=torch.long, device=input_ids.device)
            write_pos = torch.arange(num_pos_embs - self.num_mem_tokens, num_pos_embs, dtype=torch.long, device=input_ids.device)
            seg_kwargs['position_ids'] = torch.cat([
                ordinary_pos, 
                write_pos
            ]).long().unsqueeze(0)
        return seg_kwargs

    

    def pad_attention_mask(self, attention_mask, dtype=float):
        if self.num_mem_tokens in {0, None}:
            return attention_mask
        else:
            shape = list(attention_mask.shape)
            if len(shape) == 4:

                shape[-1] += self.num_mem_tokens + self.use_sink
                shape[-2] += self.num_mem_tokens + self.use_sink
                mask = torch.ones(*shape, dtype=dtype).to(attention_mask.device)
                mask[..., int(self.use_sink):-self.num_mem_tokens, int(self.use_sink):-self.num_mem_tokens] = attention_mask
                if self.use_sink:
                    mask[..., 0, 1:] = 0
                mask[..., :-self.num_mem_tokens, -self.num_mem_tokens:] = 0
                # mask = torch.tril(mask)
                if not os.environ.get("NOT_INVERT_ATTN_MASK"):
                    mask = invert_attn_mask(mask, dtype)
            else: 
                shape[-1] += self.num_mem_tokens + self.use_sink
                mask = torch.ones(*shape, dtype=dtype).to(attention_mask.device)
                mask[..., int(self.use_sink):-self.num_mem_tokens] = attention_mask
            return mask.to(dtype)

    def pad_prev_seg_attn_mask(self, prev_seg_attn_mask, dtype=float):
        if self.num_mem_tokens in {0, None}:
            return prev_seg_attn_mask
        else:
            shape = list(prev_seg_attn_mask.shape)
            if len(shape) == 4:
                shape[-2] += self.num_mem_tokens + self.use_sink
                mask = torch.ones(*shape, dtype=dtype).to(prev_seg_attn_mask.device)
                mask[..., int(self.use_sink):-self.num_mem_tokens, :] = prev_seg_attn_mask
                if self.use_sink:
                    mask[..., 0, :] = 0
                if not os.environ.get("NOT_INVERT_ATTN_MASK"):
                    mask = invert_attn_mask(mask, dtype)
            else: 
                mask = prev_seg_attn_mask
            return mask.to(dtype)
    
    def process_output(self, model_outputs, labels, labels_mask, **kwargs):
  
        if (self.num_mem_tokens not in {0, None}) and not self.RWKV_ARMT:
            out = CausalLMOutputWithCrossAttentions()
            out['logits'] = model_outputs.logits[:, int(self.use_sink):-self.num_mem_tokens]
            if kwargs.get('output_hidden_states'):
                out['hidden_states'] = [lh[:, int(self.use_sink):-self.num_mem_tokens] for lh in model_outputs.hidden_states]
            if kwargs.get('output_attentions'):
                out['attentions'] = model_outputs['attentions']
        else:
            out = model_outputs

        if labels is not None:
            labels = labels[..., 1:].contiguous()
            flat_labels = labels.view(-1)
            
            if labels_mask is not None:
                flat_mask = labels_mask[..., :-1].contiguous().view(-1)
                flat_labels = flat_labels[flat_mask]
            
            # Use optimized linear cross-entropy if available
            if CUT_CROSS_ENTROPY_AVAILABLE and hasattr(self.model, 'embed_out'):
                # Get hidden states from the last layer (before LM head)
                if 'hidden_states' in model_outputs and model_outputs.hidden_states is not None:
                    # Use the last hidden state
                    hidden_states = model_outputs.hidden_states[-1]
                    # Remove memory tokens from hidden states
                    if self.num_mem_tokens not in {0, None}:
                        hidden_states = hidden_states[:, int(self.use_sink):-self.num_mem_tokens]
                    # Shift for next token prediction
                    hidden_states = hidden_states[..., :-1, :].contiguous()
                    flat_hidden_states = hidden_states.view(-1, hidden_states.size(-1))
                    
                    if labels_mask is not None:
                        flat_hidden_states = flat_hidden_states[flat_mask]
                    
                    # Get LM head weights
                    lm_head_weights = self.model.embed_out.weight  # Shape: (vocab_size, hidden_size)
                    
                    # Use linear_cross_entropy with hidden states and LM head weights
                    ce_loss = linear_cross_entropy(
                        flat_hidden_states,  # embeddings
                        lm_head_weights,    # classifier weights
                        flat_labels,        # targets
                        reduction='sum'
                    )
                else:
                    # Fallback to standard approach if hidden states not available
                    logits = out['logits'][..., :-1, :].contiguous()
                    flat_logits = logits.view(-1, logits.size(-1))
                    if labels_mask is not None:
                        flat_logits = flat_logits[flat_mask]
                    ce_loss_fn = CrossEntropyLoss(reduction='sum')
                    ce_loss = ce_loss_fn(flat_logits, flat_labels)
            else:
                # Fallback to standard CrossEntropyLoss
                logits = out['logits'][..., :-1, :].contiguous()
                flat_logits = logits.view(-1, logits.size(-1))
                if labels_mask is not None:
                    flat_logits = flat_logits[flat_mask]
                ce_loss_fn = CrossEntropyLoss(reduction='sum')
                ce_loss = ce_loss_fn(flat_logits, flat_labels)
            
            if labels_mask is not None:
                denom = labels_mask[..., :-1].contiguous().view(-1).sum()
            else:
                denom = (flat_labels != -100).sum()
            denom = torch.clamp(denom, min=1)
            out['ce_loss'] = ce_loss / denom

        if kwargs.get('use_cache', False):
            out['past_key_values'] = model_outputs.past_key_values
        if self.act_on and self.act_type == 'model':
            out['remainders'] = model_outputs['remainders']
            out['n_updates'] = model_outputs['n_updates']
        return out
    
    def generate(self, input_ids, attention_mask, zero_mem=False, **generate_kwargs):
        if zero_mem:
            self.zero_mem()
        
        
        self.generate_mode(True)
        seg_kwargs = self.process_input(input_ids, attention_mask=attention_mask)
        out = self.model.generate(
            inputs_embeds=seg_kwargs['inputs_embeds'][:, :-self.num_mem_tokens], 
            attention_mask=seg_kwargs['attention_mask'][:, :-self.num_mem_tokens], 
            **generate_kwargs
        )
        self.generate_mode(False)
        return out
    
    def update_past_key_values_sw(self, past_key_values, window_size):
        past_key_values = past_key_values.to_legacy_cache()
        past_key_values = [
            [
                k_or_v[..., -(window_size+self.use_sink):, :]
                for k_or_v in seg_kv
            ]
            for seg_kv in past_key_values
        ]
        past_key_values = DynamicCache.from_legacy_cache(past_key_values)
        return past_key_values
    
    def greedy_generate_sw(self, input_ids, attention_mask, prev_attn_mask, **generate_kwargs):
        self.generate_mode(True)
        window_size = generate_kwargs['window_size']
        max_new_tokens = generate_kwargs['max_new_tokens']
        past_key_values = self.update_past_key_values_sw(generate_kwargs['past_key_values'], window_size)
        eos_token_id = generate_kwargs['eos_token_id']
        prev_attn_mask_2d = prev_attn_mask.clone()
        attention_mask_2d = attention_mask.clone()
        
        attention_mask = attn_mask_to_4d(attention_mask, upper=False, query_len=attention_mask.size(-1))
        prev_attn_mask = attn_mask_to_4d(prev_attn_mask, upper=True, query_len=attention_mask.size(-1))
        seg_kwargs = self.process_input(input_ids=input_ids, attention_mask=attention_mask, prev_attn_mask=prev_attn_mask, past_key_values=past_key_values)
        seg_kwargs['inputs_embeds'] = seg_kwargs['inputs_embeds'][..., :-self.num_mem_tokens, :]
        seg_kwargs['attention_mask'] = seg_kwargs['attention_mask'][..., :-self.num_mem_tokens, :-self.num_mem_tokens]
        outputs = self.model(**seg_kwargs, use_cache=True)
        
        next_token_logits = outputs.logits[:, -1, :]

        past_key_values = outputs.past_key_values
        past_key_values = self.update_past_key_values_sw(past_key_values, window_size)

        generated_ids = None
        sw_attention_mask = torch.cat([prev_attn_mask_2d, torch.ones(attention_mask_2d.size(0), 1).to(prev_attn_mask_2d.device), attention_mask_2d], dim=-1)

        for i in range(max_new_tokens):
            # print(next_token_logits[..., :5])
            next_token_id = torch.argmax(next_token_logits, dim=-1).unsqueeze(-1)
            
            if generated_ids is not None:
                generated_ids = torch.cat([generated_ids, next_token_id], dim=-1)
            else:
                generated_ids = next_token_id
            next_input = next_token_id
            
            sw_attention_mask = torch.cat([sw_attention_mask, torch.ones_like(next_token_id).to(sw_attention_mask.device)], dim=-1)[..., -window_size-1-self.use_sink:]
            with torch.no_grad():
                outputs = self.model(
                    input_ids=next_input,
                    attention_mask=sw_attention_mask,
                    past_key_values=past_key_values,
                    use_cache=True,
                    cache_position=torch.full((1,), window_size + i + input_ids.size(-1) + self.use_sink).to(input_ids.device)
                )
                past_key_values = self.update_past_key_values_sw(outputs.past_key_values, window_size)
                next_token_logits = outputs.logits[:, -1, :]
                
                if (next_token_id[:, 0] == eos_token_id).all():
                    break
        self.generate_mode(False)
        return generated_ids
            

    def apply_layers(self, hidden_states, causal_mask, position_ids, cache_position, position_embeddings, update_mem=True):
        if not update_mem:
            tmp = []
            for i in range(len(self.layers)):
                tmp.append(self.layers[i].forward)
                self.layers[i].forward = self.layers[i].forward_no_update

        for layer in self.get_layers():
            hidden_states = layer(
                    hidden_states,
                    attention_mask=causal_mask,
                    position_ids=position_ids,
                    cache_position=cache_position,
                    position_embeddings=position_embeddings,
                )[0]

        if not update_mem:
            for i, layer in enumerate(self.get_layers()):
                layer.forward = tmp[i]
        return hidden_states
        
    
    def gptneox_forward_act(self, inputs_embeds, labels=None, labels_mask=None, zero_mem=False, attention_mask=None, **kwargs):
            
            drop = self.model.gpt_neox.emb_dropout
            hidden_states = drop(inputs_embeds)
            seq_length = hidden_states.shape[1]
            cache_position = torch.arange(0, seq_length, device=hidden_states.device)
            position_ids = cache_position.unsqueeze(0)

            position_embeddings = self.model.gpt_neox.rotary_emb(hidden_states, position_ids)
            causal_mask = self.model.gpt_neox._update_causal_mask(
                attention_mask, hidden_states, cache_position, None, False
            )

            out, (remainders, n_updates) = self.act(
                state=hidden_states,
                inputs=hidden_states,
                fn_no_update=lambda *args, **kwargs: self.apply_layers(*args, **kwargs, update_mem=False),
                fn_update=self.apply_layers,
                time_enc=self.timing_signal,
                pos_enc=self.position_signal,
                max_hop=self.depth,
                causal_mask=causal_mask,
                position_ids=position_ids,
                cache_position=cache_position,
                position_embeddings=position_embeddings
            )
            hidden_states = self.model.gpt_neox.final_layer_norm(out)

            lm_logits = self.model.embed_out(hidden_states)
            return ARMTOutput(logits=lm_logits, n_updates=n_updates, remainders=remainders)

class AssociativeRecurrentWrapper(torch.nn.Module):
    def __init__(self, memory_cell, **rmt_kwargs):
        super().__init__()
        
        self.memory_cell = memory_cell
        self.rmt_config = rmt_kwargs
        self.last_state = None

    def gradient_checkpointing_enable(self, *args, **kwargs):
        self.memory_cell.model.gradient_checkpointing_enable(*args, **kwargs)

    def process_segment(self, segment_kwargs, next_seg_len=None):
        sliding_window = self.rmt_config['sliding_window'] if 'sliding_window' in self.rmt_config else False
        attend_to_previous_input = self.rmt_config['attend_to_previous_input'] if 'attend_to_previous_input' in self.rmt_config else False
        attn_mask = segment_kwargs['attention_mask']
        seg_len = segment_kwargs['input_ids'].size(-1)

        segment_kwargs['use_cache'] = sliding_window
        if segment_kwargs.get('past_key_values') is None:
            segment_kwargs['past_key_values'] = None
        if segment_kwargs.get('prev_attn_mask') is None:
            segment_kwargs['prev_attn_mask'] = None
        segment_kwargs['zero_mem'] = False
        if sliding_window or attend_to_previous_input:
            segment_kwargs['attention_mask'] = attn_mask_to_4d(attn_mask, upper=False, query_len=seg_len)
        
        if 'state' in segment_kwargs and segment_kwargs['state'] is None:
            segment_kwargs.pop('state')
        
        num_mem_tokens = self.memory_cell.num_mem_tokens
        cell_out = self.memory_cell(**segment_kwargs)
        state = cell_out.get('state')
        if (sliding_window or attend_to_previous_input) and next_seg_len is not None:
            prev_attn_mask = attn_mask_to_4d(attn_mask, upper=True, query_len=next_seg_len)
        else: 
            prev_attn_mask = None
        if sliding_window:
            past_key_values = [
                [
                    k_or_v[..., -(num_mem_tokens+seg_len):k_or_v.size(-2)-num_mem_tokens, :].detach() 
                    for k_or_v in seg_kv
                ]
                for seg_kv in cell_out['past_key_values']
            ]
            if not isinstance(cell_out['past_key_values'], tuple) and not isinstance(cell_out['past_key_values'], list):
                past_key_values = cell_out['past_key_values'].from_legacy_cache(past_key_values)
            else:
                past_key_values = DynamicCache.from_legacy_cache(past_key_values)
        else:
            past_key_values = None
        next_segment_kwargs = dict()
        next_segment_kwargs['use_cache'] = sliding_window
        next_segment_kwargs['past_key_values'] = past_key_values
        next_segment_kwargs['prev_attn_mask'] = prev_attn_mask
        next_segment_kwargs['zero_mem'] = False
        if state is not None:
            next_segment_kwargs['state'] = state
        return cell_out, next_segment_kwargs

    def forward(self, 
                input_ids, 
                labels=None, 
                labels_mask=None, 
                inputs_embeds=None, 
                attention_mask=None, 
                output_attentions=None, 
                output_hidden_states=None,
                input_segmented=False,
                output_only_last_segment=False,
                use_previous_batch_state=torch.zeros(1),
                num_items_in_batch=None,  # Added to handle HF Trainer compatibility
                **kwargs  # Added to handle any other unexpected kwargs
                ):
        if input_segmented:
            n_segs = input_ids.shape[1] if not (input_ids is None) else inputs_embeds.shape[1]
            segmented = [dict(
                input_ids=input_ids[:, i] if not (input_ids is None) else None, 
                inputs_embeds=inputs_embeds[:, i] if not (inputs_embeds is None) else None, 
                attention_mask=attention_mask[:, i],
                labels=labels[:, i] if not (labels is None) else None, 
                labels_mask=labels_mask[:, i] if not (labels_mask is None) else None, 
            ) for i in range(n_segs)]
            labels = torch.cat([labels[:, i] for i in range(n_segs)], dim=1)
            if labels_mask is not None:
                labels_mask = torch.cat([labels_mask[:, i] for i in range(n_segs)], dim=1)
        else:
            segmented = self.segment(input_ids=input_ids, inputs_embeds=inputs_embeds, attention_mask=attention_mask, labels=labels, labels_mask=labels_mask)
        
        cell_outputs = []
        if not use_previous_batch_state.all() or self.last_state is None:
            self.memory_cell.zero_mem()
            state = None
        else: 
            self.memory_cell.detach_mem()
            state = self.last_state
        next_seg_kwargs = dict(state=state)
        for seg_num, segment in enumerate(segmented):
            if seg_num != len(segmented) - 1:
                next_seg_len = segmented[seg_num + 1]['input_ids'].size(-1)
            else:
                next_seg_len = None
            # Pass num_items_in_batch to segment processing
            segment_with_kwargs = dict(**segment, **next_seg_kwargs)
            if kwargs.get('num_items_in_batch') is not None:
                segment_with_kwargs['num_items_in_batch'] = kwargs['num_items_in_batch']
            cell_out, next_seg_kwargs = self.process_segment(segment_with_kwargs, next_seg_len=next_seg_len)
            if (not output_only_last_segment) or (seg_num == len(segmented) - 1):
                cell_outputs.append(cell_out)

        out = self.process_outputs(cell_outputs, labels=labels, 
                                   labels_mask=labels_mask,
                                   output_attentions=output_attentions, 
                                   output_hidden_states=output_hidden_states,
                                   num_items_in_batch=kwargs.get('num_items_in_batch'))
        
        if not self.training:
            self.memory_cell.zero_mem()
            self.last_state = None
        return out

    def segment(self, **kwargs):
        segments = []
        for k, tensor in kwargs.items():
            if tensor is not None:
                k_segments = self.split_tensor(tensor)
                for s, k_seg in enumerate(k_segments):
                    if s < len(segments):
                        segments[s][k] = k_seg
                    else:
                        segments.append({k: k_seg})

        return segments
    
    def split_tensor(self, tensor):
        align = self.rmt_config.get('segment_alignment')
        segment_size = self.rmt_config.get('segment_size')
        if align in {'left', None}:
            split_inds = list(range(0, tensor.shape[1], segment_size)) + [tensor.shape[1]]
            segments = [tensor[:, start:end] for (start, end) in zip(split_inds, split_inds[1:])]
        elif align in {'right', None}:
            split_inds = (list(range(tensor.shape[1], 0, -segment_size)) + [0])[::-1]
            segments = [tensor[:, start:end] for (start, end) in zip(split_inds, split_inds[1:])]
        elif align == 'center':
            n_seg = math.ceil(tensor.shape[1] / segment_size)
            segments = torch.chunk(tensor, n_seg, dim=1)
        else:
            raise NotImplementedError
        return segments

    def process_outputs(self, cell_outputs, **kwargs):
        out = ARMTOutput()
        full_logits = torch.cat([o.logits for o in cell_outputs], dim=1)
        
        labels = kwargs.get('labels')
        if labels is not None:
            labels = labels[:, -full_logits.size(1):]
            shift_labels = labels[..., 1:].contiguous()
            flat_labels = shift_labels.view(-1)
            
            labels_mask = kwargs.get('labels_mask')
            if labels_mask is not None:
                labels_mask = labels_mask[:, -full_logits.size(1):]
                shift_mask = labels_mask[..., :-1].contiguous()
                flat_labels = flat_labels[shift_mask.view(-1)]
            
            # Use optimized linear cross-entropy if available
            if CUT_CROSS_ENTROPY_AVAILABLE and hasattr(self.memory_cell.model, 'embed_out'):
                # Get hidden states from the last segment
                if cell_outputs and 'hidden_states' in cell_outputs[-1] and cell_outputs[-1].hidden_states is not None:
                    # Concatenate hidden states from all segments
                    full_hidden_states = torch.cat([o.hidden_states[-1] for o in cell_outputs], dim=1)
                    # Shift for next token prediction
                    shift_hidden_states = full_hidden_states[..., :-1, :].contiguous()
                    flat_hidden_states = shift_hidden_states.view(-1, shift_hidden_states.size(-1))
                    
                    if labels_mask is not None:
                        flat_hidden_states = flat_hidden_states[shift_mask.view(-1)]
                    
                    # Get LM head weights
                    lm_head_weights = self.memory_cell.model.embed_out.weight  # Shape: (vocab_size, hidden_size)
                    
                    # Use linear_cross_entropy with hidden states and LM head weights
                    loss = linear_cross_entropy(
                        flat_hidden_states,  # embeddings
                        lm_head_weights,    # classifier weights
                        flat_labels,        # targets
                        reduction='sum'
                    )
                else:
                    # Fallback to standard approach if hidden states not available
                    shift_logits = full_logits[..., :-1, :].contiguous()
                    flat_logits = shift_logits.view(-1, shift_logits.size(-1))
                    if labels_mask is not None:
                        flat_logits = flat_logits[shift_mask.view(-1)]
                    loss_fct = CrossEntropyLoss(reduction='sum')
                    loss = loss_fct(flat_logits, flat_labels)
            else:
                # Fallback to standard CrossEntropyLoss
                shift_logits = full_logits[..., :-1, :].contiguous()
                flat_logits = shift_logits.view(-1, shift_logits.size(-1))
                if labels_mask is not None:
                    flat_logits = flat_logits[shift_mask.view(-1)]
                loss_fct = CrossEntropyLoss(reduction='sum')
                loss = loss_fct(flat_logits, flat_labels)
            
            if labels_mask is not None:
                # Use the same mask used to filter flat logits/labels
                denom = labels_mask[..., :-1].contiguous().view(-1).sum()
            else:
                denom = (flat_labels != -100).sum()
            denom = torch.clamp(denom, min=1)
            out['loss'] = loss / denom
        else:
            out['loss'] = 0 
        if ('HF_Trainer' not in os.environ) or not os.environ['HF_Trainer']:
            out['ce_loss'] = out['loss']
        
        out['logits'] = full_logits
        segment_keys = ['loss', 'logits']
        if kwargs.get('output_attentions'):
            segment_keys.append('attentions')
        if kwargs.get('output_hidden_states'):
            # Only process hidden_states if all cell outputs have them
            if all(hasattr(o, 'hidden_states') and o.hidden_states is not None for o in cell_outputs):
                full_hidden_states = tuple([torch.cat(layer_hs, dim=1) for layer_hs in zip(*[o.hidden_states for o in cell_outputs])])
                segment_keys.append('hidden_states')
                out['hidden_states'] = full_hidden_states
        if ('HF_Trainer' not in os.environ) or not os.environ['HF_Trainer']:
            for seg_num, o in enumerate(cell_outputs):
                for key, value in o.items():
                    if any([sk in key for sk in segment_keys]):
                        out[f'{key}_{seg_num}'] = value

        remainders = []
        n_updates = []
        act_on = self.rmt_config['act_on'] if 'act_on' in self.rmt_config else False
        if act_on:
          if self.memory_cell.act_type != 'model':
            for layer in self.memory_cell.get_layers():
                remainders.append(layer.remainders / layer.segments_passed)
                n_updates.append(layer.n_updates / layer.segments_passed)
            remainders = torch.mean(torch.stack(remainders, dim=0))
            n_updates = torch.mean(torch.stack(n_updates, dim=0))
          else:
            remainders = torch.mean(torch.stack([o['remainders'] for o in cell_outputs], dim=0))
            n_updates = torch.mean(torch.stack([o['n_updates'] for o in cell_outputs], dim=0))
          out['n_updates'] = n_updates.detach().cpu()
          out['remainders'] = remainders.detach().cpu()
          time_penalty = self.rmt_config['time_penalty']
          out['loss'] = out['loss'] + time_penalty * remainders
        
        return out 
    
    def generate(self, input_ids, attention_mask, **generate_kwargs):
        self.memory_cell.zero_mem()
        segmented = self.segment(input_ids=input_ids, attention_mask=attention_mask)
        next_seg_kwargs = dict()
        for seg_num, segment in enumerate(segmented[:-1]):
            next_seg_len = segmented[seg_num + 1]['input_ids'].size(-1)
            _, next_seg_kwargs = self.process_segment(dict(**segment, **next_seg_kwargs), next_seg_len=next_seg_len)
        
        final_segment = segmented[-1]
        assert next_seg_kwargs.get('past_key_values') is None or isinstance(next_seg_kwargs.get('past_key_values'), Cache), "Sliding Window generation is not implemented for legacy cache"
        if next_seg_kwargs.get('past_key_values') is not None:
            prev_attn_mask = segmented[-2]['attention_mask']
            legacy_cache = next_seg_kwargs['past_key_values'].to_legacy_cache()
            seg_len = segmented[-2]['input_ids'].size(-1)
            cache = DynamicCache().from_legacy_cache(legacy_cache)
            generate_kwargs['past_key_values'] = cache
            generate_kwargs['window_size'] = seg_len
            final_segment['prev_attn_mask'] = prev_attn_mask
            out = self.memory_cell.greedy_generate_sw(**final_segment, **generate_kwargs)
            return out
        else:
            out = self.memory_cell.generate(**final_segment, **generate_kwargs)
            return out


# ---- model.py ----
import math
import torch
from torch.nn import CrossEntropyLoss
from transformers import PreTrainedModel, PretrainedConfig
from transformers.modeling_outputs import CausalLMOutputWithCrossAttentions
from transformers.cache_utils import Cache, DynamicCache
from torch.nn.functional import relu as r
import torch.nn.functional as F
import os

# inlined language_modeling: removed import AssociativeMemoryCell, AssociativeRecurrentWrapper, attn_mask_to_4d, invert_attn_mask


class ARMTConfig(PretrainedConfig):
    model_type = "armt"

    def __init__(self,
                 base_model_name=None,
                 base_model_config=None,
                 num_mem_tokens=16,
                 d_mem=512,

                 segment_size=512,
                 segment_alignment="left",
                 sliding_window=False,
                 attend_to_previous_input=False,
                 use_sink=False,
                 layers_attr="model.layers",
                 wrap_pos=False,
                 correction=True,
                 n_heads=1,
                 use_denom=True,
                 gating=False,
                 freeze_mem=False,
                 act_on=False,
                 max_hop=4,
                 act_type="associative",
                 act_format="linear",
                 noisy_halting=False,
                 constant_depth=False,
                 time_penalty=0.0,
                 **kwargs):
        super().__init__(**kwargs)
        # Validate mutual exclusivity
        if (base_model_name is not None) and (base_model_config is not None):
            raise ValueError("Exactly one of `base_model_name` or `base_model_config` must be provided. Set the other to None.")
        self.base_model_name = base_model_name
        # Optional alternative to base_model_name: a config (dict/PretrainedConfig/name-or-path)
        self.base_model_config = base_model_config
        self.num_mem_tokens = num_mem_tokens
        self.d_mem = d_mem

        self.segment_size = segment_size
        self.segment_alignment = segment_alignment
        self.sliding_window = sliding_window
        self.attend_to_previous_input = attend_to_previous_input
        self.use_sink = use_sink
        self.layers_attr = layers_attr
        self.wrap_pos = wrap_pos
        self.correction = correction
        self.n_heads = n_heads
        self.use_denom = use_denom
        self.gating = gating
        self.freeze_mem = freeze_mem
        self.act_on = act_on
        self.max_hop = max_hop
        self.act_type = act_type
        self.act_format = act_format
        self.noisy_halting = noisy_halting
        self.constant_depth = constant_depth
        self.time_penalty = time_penalty

    def get(self, attr: str, default=None):
        if hasattr(self, attr):
            return getattr(self, attr)
        else:
            return default


class ARMTForCausalLM(PreTrainedModel):
    config_class = ARMTConfig

    def __init__(self, config: ARMTConfig, **kwargs):
        super().__init__(config, **kwargs)
        from transformers import AutoConfig, AutoModelForCausalLM
        
        # Build base model either from name (pretrained weights) or from provided config
        base_model = None
        if getattr(config, 'base_model_name', None) is not None and getattr(config, 'base_model_config', None) is not None:
            raise ValueError("Exactly one of `base_model_name` or `base_model_config` must be provided in ARMTConfig.")
        bm_cfg = getattr(config, 'base_model_config', None)
        if bm_cfg is not None:
            # Prefer explicit config when provided
            if isinstance(bm_cfg, PretrainedConfig) and getattr(bm_cfg, 'model_type', None) != ARMTConfig.model_type:
                resolved_cfg = bm_cfg
            elif isinstance(bm_cfg, dict):
                if 'model_type' not in bm_cfg:
                    raise ValueError("`base_model_config` dict must include a 'model_type' key (e.g., 'gpt_neox', 'llama').")
                config_cls_or_instance = AutoConfig.for_model(bm_cfg['model_type'])
                # If an instance was returned, update it; if a class was returned, construct from dict
                if isinstance(config_cls_or_instance, PretrainedConfig):
                    resolved_cfg = config_cls_or_instance
                    for k, v in bm_cfg.items():
                        setattr(resolved_cfg, k, v)
                else:
                    resolved_cfg = config_cls_or_instance.from_dict(bm_cfg)
            elif isinstance(bm_cfg, str):
                # Treat as a name or path to load a config
                resolved_cfg = AutoConfig.from_pretrained(bm_cfg)
            else:
                raise TypeError("`base_model_config` must be a transformers.PretrainedConfig, dict, or str (name/path)")
            base_model = AutoModelForCausalLM.from_config(resolved_cfg)
        elif getattr(config, 'base_model_name', None):
            base_model = AutoModelForCausalLM.from_pretrained(config.base_model_name)
        else:
            raise ValueError("ARMTForCausalLM requires either `base_model_config` or `base_model_name` in ARMTConfig.")

        self.armt_config = config
        
        # Create the associative memory cell
        memory_cell = AssociativeMemoryCell(
            base_model=base_model,
            num_mem_tokens=config.num_mem_tokens,
            d_mem=config.d_mem,
            layers_attr=config.layers_attr,
            wrap_pos=config.wrap_pos,
            correction=config.correction,
            n_heads=config.n_heads,
            use_denom=config.use_denom,
            gating=config.gating,
            freeze_mem=config.freeze_mem,
            act_on=config.act_on,
            max_hop=config.max_hop,
            act_type=config.act_type,
            # Optional extras
            constant_depth=config.get('constant_depth', False),
            act_format=config.get('act_format', 'linear'),
            noisy_halting=config.get('noisy_halting', False),
            attend_to_previous_input=config.attend_to_previous_input,
            use_sink=config.use_sink
        )
        
        # Create the associative recurrent wrapper
        self.armt = AssociativeRecurrentWrapper(
            memory_cell,
            segment_size=config.segment_size,
            segment_alignment=config.segment_alignment,
            sliding_window=config.sliding_window,
            attend_to_previous_input=config.attend_to_previous_input,
            act_on=config.act_on,
            time_penalty=config.time_penalty
        )

    def forward(
        self,
        input_ids=None,
        labels=None,
        labels_mask=None,
        inputs_embeds=None,
        attention_mask=None,
        output_attentions=None,
        output_hidden_states=None,
        input_segmented=False,
        output_only_last_segment=False,
        num_items_in_batch=None,
    ):
        return self.armt(
            input_ids=input_ids,
            labels=labels,
            labels_mask=labels_mask,
            inputs_embeds=inputs_embeds,
            attention_mask=attention_mask,
            output_attentions=output_attentions,
            output_hidden_states=output_hidden_states,
            input_segmented=input_segmented,
            output_only_last_segment=output_only_last_segment,
            num_items_in_batch=num_items_in_batch,
        )

    def generate(self, *args, **kwargs):
        return self.armt.generate(*args, **kwargs)

    def load_state_dict(self, state_dict, strict=True, assign=False):
        try:
            return super().load_state_dict(state_dict, strict, assign)
        except RuntimeError:
            print("Failed to load state, retrying with ARMT loader.")
            self.armt.load_state_dict(state_dict, strict=True, assign=assign)
            print("Success!")

    @classmethod
    def from_pretrained(cls, pretrained_model_name_or_path, config=None, *args, **kwargs):
        # Delegate to the base class to benefit from full shard/format support
        return super().from_pretrained(pretrained_model_name_or_path, *args, config=config, **kwargs)

    def gradient_checkpointing_enable(self, *args, **kwargs):
        self.armt.gradient_checkpointing_enable(*args, **kwargs) 

# ---- inner_loop.py ----
import math
import os
import inspect
from typing import Optional, Tuple, Callable

import torch
import torch.nn.functional as F
from torch import nn
from torch.nn import CrossEntropyLoss
from transformers import PreTrainedModel, PretrainedConfig
from transformers.cache_utils import DynamicCache
import warnings
# inlined ARMTConfig: removed import

try:
    from liger_kernel.transformers import apply_liger_kernel_to_llama
    LIGER_KERNEL_AVAILABLE = True
except ImportError:
    print("*** Can't import liger_kernel ***")
    LIGER_KERNEL_AVAILABLE = False
except Exception as e:
    print("*** Can't import liger_kernel ***")
    raise e

# Reuse utilities from the existing implementation to ensure identical math
# inlined language_modeling: removed import DPFP, invert_attn_mask as _invert_attn_mask, attn_mask_to_4d

def reverse_invert_attn_mask(mask: torch.Tensor) -> torch.Tensor:
    if os.environ.get("NOT_INVERT_ATTN_MASK"):
        return mask
    mask = mask.clone().long()
    mask[mask > -1] = 1
    mask[mask < -1] = 0
    return mask

def attn_mask_to_2d(mask: torch.Tensor) -> torch.Tensor:
    mask = reverse_invert_attn_mask(mask)
    mask = torch.any(mask, dim=-2)
    mask = torch.any(mask, dim=1)
    return mask.long()

def is_empty_past_key_values(past_key_values: Optional[DynamicCache], layer_idx: int) -> bool:
    if past_key_values is None:
        return True
    if len(past_key_values.layers) == 0:
        return True
    if len(past_key_values.layers) <= layer_idx:
        return True
    if past_key_values.layers[layer_idx].keys is None:
        return True
    return False

invert_attn_mask = lambda mask, dtype: (_invert_attn_mask(mask, dtype) if not os.environ.get("NOT_INVERT_ATTN_MASK") else mask)

def segment_tensor(t: torch.Tensor, start_idx: int, end_idx: int, seq_len: int) -> torch.Tensor:
    if not isinstance(t, torch.Tensor):
        return t
    # common cases: (bsz, seq_len, ...), (bsz, seq_len), (seq_len, ...)
    if t.dim() >= 2 and t.size(1) == seq_len:
        return t[:, start_idx:end_idx, ...]
    return t

class InnerLoopAssociativeLayerWrapper(nn.Module):
    """
    A per-layer wrapper that performs associative read/write within the layer by
    splitting the incoming full sequence into fixed-size segments on the fly.

    Unlike the outer-loop design (which segments inputs before the model), this
    module receives the full, unsplit hidden sequence and internally iterates
    over segments:
      1) Optional associative READ is applied to the segment's hidden states
         based on the current associative memory (W_mem, z).
      2) Memory tokens are appended to the segment and the underlying transformer
         layer is executed only on this augmented segment.
      3) The resulting memory token outputs are used to WRITE/update the
         associative memory.
      4) The transformed real-token outputs replace the corresponding slice in
         the layer output for the full sequence.

    This preserves identical behavior w.r.t. memory math while avoiding any
    outer recurrent wrapper.
    """

    def __init__(
        self,
        layer: nn.Module,
        d_model: int,
        num_mem_tokens: int,
        d_mem: int,
        segment_size: int,
        n_heads: int = 1,
        correction: bool = True,
        use_denom: bool = True,
        gating: bool = False,
        use_sink: bool = False,
        sliding_window: bool = False,
        get_memory_fn: Optional[Callable[[], torch.Tensor]] = None,
        get_sink_fn: Optional[Callable[[], Optional[torch.Tensor]]] = None,
        rotary_fn: Optional[Callable[[torch.Tensor, torch.Tensor], Tuple[torch.Tensor, torch.Tensor]]] = None,
        read_prev_states_fn: Optional[Callable[[int, int, torch.device, torch.dtype], Tuple[torch.Tensor, Optional[torch.Tensor]]]] = None,
        write_states_fn: Optional[Callable[[int, torch.Tensor, Optional[torch.Tensor]], None]] = None,
        info: Optional[dict] = None,
    ) -> None:
        super().__init__()
        self.info = info
        self.layer = layer
        self.d_model = d_model
        self.num_mem_tokens = int(num_mem_tokens or 0)
        self.d_mem = d_mem
        self.segment_size = int(segment_size)
        self.n_heads = n_heads
        self.gating = gating
        self.use_denom = use_denom
        self.correction = correction
        self.use_sink = bool(use_sink)
        self.sliding_window = bool(sliding_window)

        # DPFP feature map dimensions
        nu = 3
        self.d_key = 2 * nu * d_mem

        assert self.d_mem % n_heads == 0 and self.d_model % n_heads == 0

        # Match the dtype to the wrapped layer
        layer_dtype = next(self.layer.parameters()).dtype

        # Readout/query/key/value projections for associative memory
        self.W_mq = nn.Linear(d_model, d_mem, bias=False, dtype=layer_dtype)
        self.W_mk = nn.Linear(d_model, d_mem, bias=False, dtype=layer_dtype)
        self.W_mv = nn.Linear(d_model, d_model, bias=False, dtype=layer_dtype)
        if gating:
            self.W_mb = nn.Linear(d_model, d_model, dtype=layer_dtype)
        else:
            self.W_mb = nn.Linear(d_model, n_heads, dtype=layer_dtype)
        torch.nn.init.zeros_(self.W_mv.weight)

        self.phi = DPFP(nu)

        # Runtime flags/counters
        self.generate_mode = False
        self.seg_num = 0

        # Lightweight accessors to shared trainable memory tensors owned by the top-level model.
        # These are callables, not Modules/Parameters stored as attributes, to avoid submodule cycles.
        self._get_memory = get_memory_fn
        self._get_sink = get_sink_fn
        self._rotary_fn = rotary_fn
        self._read_prev_states = read_prev_states_fn
        self._write_states = write_states_fn

        self.memory_state = None

    # ----- helpers for heads reshaping -----
    def _to_heads(self, x: torch.Tensor) -> torch.Tensor:
        bsz, seq_len, d_model = x.shape
        x = x.reshape(bsz, seq_len, self.n_heads, d_model // self.n_heads)
        x = x.permute(0, 2, 1, 3)
        return x

    def _from_heads(self, x: torch.Tensor) -> torch.Tensor:
        bsz, n_heads, seq_len, d_head = x.shape
        x = x.permute(0, 2, 1, 3).reshape(bsz, seq_len, n_heads * d_head)
        return x

    # ----- associative read -----
    def associate(self, hidden_states: torch.Tensor) -> torch.Tensor:
        raise NotImplementedError("associate() is unused in inner-loop; uses local memory helpers instead")

    # ----- associative write -----
    def update_mem(self, mem_tokens: torch.Tensor) -> None:
        raise NotImplementedError("update_mem() is unused in inner-loop; uses local memory helpers instead")

    # ----- memory state management -----
    def zero_mem(self) -> None:
        self.memory_state = None

    def detach_mem(self) -> None:
        self.memory_state = (self.memory_state[0].detach(), self.memory_state[1].detach()) if self.memory_state is not None else None

    def freeze_mem(self) -> None:
        self.W_mb.weight.requires_grad = False
        self.W_mb.bias.requires_grad = False
        self.W_mq.weight.requires_grad = False
        self.W_mk.weight.requires_grad = False
        self.W_mv.weight.requires_grad = False

    # ----- utilities -----
    def _get_segment_positions(
        self, position_ids: Optional[torch.LongTensor], start: int, end: int, device: torch.device
    ) -> torch.LongTensor:
        # If original absolute positions are provided, slice and extend for sink/memory
        if position_ids is not None:
            return position_ids[:, start:end]
        else:
            position_ids = torch.arange(start, end, device=device).long().unsqueeze(0)
            return position_ids


    def pad_attention_mask(self, attention_mask: torch.Tensor, dtype: torch.dtype):
        if self.num_mem_tokens in {0, None} and not self.use_sink:
            return attention_mask
        shape = list(attention_mask.shape)
        if len(shape) == 4:
            shape[-1] += self.num_mem_tokens + int(self.use_sink)
            shape[-2] += self.num_mem_tokens + int(self.use_sink)
            mask = torch.ones(*shape, dtype=dtype).to(attention_mask.device)
            mask[..., int(self.use_sink):-self.num_mem_tokens, int(self.use_sink):-self.num_mem_tokens] = attention_mask
            if self.use_sink:
                mask[..., 0, 1:] = 0
            mask[..., :-self.num_mem_tokens, -self.num_mem_tokens:] = 0
        elif len(shape) == 2:
            shape[-1] += self.num_mem_tokens + int(self.use_sink)
            mask = torch.ones(*shape, dtype=dtype).to(attention_mask.device)
            mask[..., int(self.use_sink):-self.num_mem_tokens] = attention_mask
        else:
            raise ValueError("Attention mask must be 2D or 4D")
        return mask.to(dtype)


    def _get_memory_tokens(self, batch_size: int) -> Tuple[Optional[torch.Tensor], Optional[torch.Tensor]]:
        if self._get_memory is None or self.num_mem_tokens == 0:
            return None, None
        memory = self._get_memory()
        sink = self._get_sink() if self.use_sink and self._get_sink is not None else None
        mem = memory.unsqueeze(0).expand(batch_size, -1, -1)
        if sink is not None:
            sink = sink.unsqueeze(0).expand(batch_size, -1, -1)
        return mem, sink

    # ----- helpers operating on provided memory tensors (no buffers) -----
    def _alloc_initial_mem(self, device: torch.device, dtype: torch.dtype):
        W_mem = torch.zeros(
            1,
            self.n_heads,
            self.d_key // self.n_heads,
            self.d_model // self.n_heads,
            device=device,
            dtype=dtype,
        )
        z = torch.zeros(1, self.n_heads, self.d_key // self.n_heads, device=device, dtype=dtype) if self.use_denom else None
        return W_mem, z

    def _associate_with_mem(self, hidden_states: torch.Tensor, W_mem: torch.Tensor, z: Optional[torch.Tensor]) -> torch.Tensor:
        q = self._to_heads(self.W_mq(hidden_states))
        mq = self.phi(q)
        mq = F.normalize(mq, dim=-1, p=2.0)
        num = torch.einsum("ihjk,ihkt->ihjt", mq, W_mem)
        if self.use_denom and z is not None:
            denom = torch.einsum("ihk,ihjk->ihj", z, mq)[..., None] + 1e-5
            hs = num / denom
        else:
            hs = num
        return self._from_heads(hs)

    def _update_mem_with_mem(
        self,
        mem_tokens: torch.Tensor,
        W_mem: torch.Tensor,
        z: Optional[torch.Tensor],
        first_seg: bool,
    ) -> tuple[torch.Tensor, Optional[torch.Tensor], bool]:
        k = self._to_heads(self.W_mk(mem_tokens))
        mk = self.phi(k)
        mk = F.normalize(mk, dim=-1, p=2.0)

        new_mv = self._to_heads(self.W_mv(mem_tokens))
        if not first_seg:
            num = torch.einsum("ihjk,ihkt->ihjt", mk, W_mem)
            if self.use_denom and z is not None:
                denom = torch.einsum("ihj,ihkj->ihk", z, mk)[..., None] + 1e-5
                prev_mv = num / denom
                if self.correction:
                    new_info_coef = (
                        1 - denom / (torch.linalg.norm(mk, dim=-1) ** 2)[..., None]
                    )
                    new_info_coef = torch.clip(new_info_coef, 0, 1).detach()
                else:
                    new_info_coef = 1
            else:
                prev_mv = num
                new_info_coef = 1
        else:
            prev_mv = torch.zeros_like(new_mv, device=new_mv.device)
            new_info_coef = 1

        mv = new_mv - prev_mv
        mb = self._to_heads(torch.sigmoid(self.W_mb(mem_tokens)))
        einop = f"ihjk,ihjt,ihj{'t' if self.gating else 'x'}->ihkt"
        associations = torch.einsum(einop, mk, mv, mb)
        W_mem = W_mem + associations
        if self.use_denom and z is not None:
            z = z + (new_info_coef * mk).sum(dim=-2)
        return W_mem, z, False

    
    def forward(self, hidden_states: torch.Tensor, *args, **kwargs):
        """
        Convert positional args of the wrapped HF block into keyword args by
        introspecting the block's forward signature. This prevents accidental
        misplacement (e.g., a cache object being treated as attention_mask).
        """
        # Map positional args to their parameter names (excluding self & hidden_states)
        try:
            sig = inspect.signature(self.layer.forward)
            params = list(sig.parameters.values())
            # Drop the first param which should be 'self' for bound method
            param_names = [p.name for p in params[1:]]
            # If the next parameter is hidden_states, drop it as well
            if len(param_names) > 0 and param_names[0] in {"hidden_states", "x"}:
                param_names = param_names[1:]
        except Exception:
            param_names = []

        for idx, arg in enumerate(args):
            if idx >= len(param_names):
                break
            name = param_names[idx]
            if name not in kwargs:
                kwargs[name] = arg

        # Normalize cache kwarg name to 'past_key_values'
        if "layer_past" in kwargs and "past_key_values" not in kwargs:
            layer_past = kwargs.pop("layer_past")
            try:
                if isinstance(layer_past, DynamicCache):
                    kwargs["past_key_values"] = layer_past
                else:
                    kwargs["past_key_values"] = DynamicCache.from_legacy_cache(layer_past)
            except Exception:
                kwargs["past_key_values"] = layer_past

        # Extract attention mask (avoid passing both positional & kwarg duplicates)
        attention_mask = kwargs.pop("attention_mask", None)

        return self.forward_horizontal(hidden_states, attention_mask, **kwargs)
    
    # ----- main forward (inner-loop segmentation) -----
    def forward_horizontal(self, hidden_states: torch.Tensor, attention_mask=None, *args, **kwargs):
        assert not self.generate_mode, "Generate mode is not supported for horizontal forward"
        assert attention_mask is None or attention_mask.dim() == 4, "Attention mask must be 4D"
        using_cache = not is_empty_past_key_values(kwargs.get("past_key_values"), self.info['layer'])
        assert not using_cache or (kwargs.get('past_attn_mask') is not None and kwargs.get('past_attn_mask').shape[-1] == self.segment_size), "When using cache, past_attn_mask must be provided and have the same length as the segment size"

        if isinstance(hidden_states, (tuple, list)):
            hidden_states = hidden_states[0]
        bsz, seq_len, _ = hidden_states.shape

        if attention_mask is None:
            attention_mask = torch.ones(bsz, seq_len, device=hidden_states.device, dtype=hidden_states.dtype)
            attention_mask = attn_mask_to_4d(attention_mask, upper=False, query_len=seq_len)
            attention_mask = invert_attn_mask(attention_mask, hidden_states.dtype)
        out_full = []

        # Initialize associative memory from persisted state if available
        if self.memory_state is not None:
            W_mem, z = self.memory_state
            first_seg = False
        else:
            W_mem, z = self._alloc_initial_mem(hidden_states.device, hidden_states.dtype)
            first_seg = True


        # Always use provided cache object if present, even if currently empty,
        # so upstream callers can observe in-place mutations across segments.
        provided_cache = kwargs.get("past_key_values")
        past_key_values = provided_cache if provided_cache is not None else DynamicCache()
        past_attn_mask = kwargs.get('past_attn_mask') if using_cache else None
        present_kv = None

        # helper to segment arbitrary tensor-like by time dim
        
        seg_num = 0
        for start in range(0, seq_len, self.segment_size+self.num_mem_tokens+int(self.use_sink)):
            real_start = start+int(self.use_sink)
            real_end = min(real_start + self.segment_size, seq_len-self.num_mem_tokens)
            end = real_end+self.num_mem_tokens
            seg_aug = hidden_states[:, start:end, :]
            seg_len = real_end - real_start

            attn_mask = attention_mask[:, :, real_start:real_end, real_start:real_end]

            # print("attn_mask", attn_mask[0][0])

            # Check if this is the last segment and we're in generate mode
            is_last_segment = (end >= seq_len)


            if not first_seg:
                assoc = self._associate_with_mem(seg_aug, W_mem, z)
                seg_aug = assoc + seg_aug

            # Build attention mask for this augmented segment
            seg_aug_len = seg_aug.size(1)
            
            if self.sliding_window:
                # print(attn_mask.shape, "attn_mask", "*"*100)
                # print(base_cur4d.shape, "base_cur4d", "*"*100)
                base_cur4d = reverse_invert_attn_mask(attn_mask)
                seg_mask = self.pad_attention_mask(base_cur4d, dtype=seg_aug.dtype)
                seg_mask = invert_attn_mask(seg_mask, seg_aug.dtype)

                if past_attn_mask is not None:

                    base_past4d = attn_mask_to_4d(attn_mask_to_2d(past_attn_mask), upper=True, query_len=seg_aug_len)
                    if self.use_sink:
                        base_past4d[:, :, 0, :] = 0 # sink cannot attend to others
                    # base_past4d = torch.ones_like(base_past4d)
                    base_past4d = invert_attn_mask(base_past4d, seg_aug.dtype)

                    # print(base_past4d.shape, "base_past4d", "*"*100)
                    # print(seg_mask.shape, "seg_mask", "*"*100)
                    seg_mask = torch.cat([base_past4d, seg_mask], dim=-1)
                if os.environ.get("ARMT_DEBUG_SW"):
                    print(f"[H-SEG] L{self.info['layer']} seg_len={seg_len} seg_aug_len={seg_aug_len} mask={tuple(seg_mask.shape)}")
            else:
                base_cur4d = reverse_invert_attn_mask(attn_mask)
                seg_mask = self.pad_attention_mask(base_cur4d, dtype=seg_aug.dtype)
                seg_mask = invert_attn_mask(seg_mask, seg_aug.dtype)
            # print("seg_mask", reverse_invert_attn_mask(seg_mask)[0][0])
            # print("seg_mask", seg_mask.shape)
            seg_pos_ids = self._get_segment_positions(kwargs.get("position_ids", None), start, end, seg_aug.device)

            # Segment incoming args/kwargs by time where applicable
            seg_args = tuple(segment_tensor(a, start, end, seq_len) if isinstance(a, torch.Tensor) else a for a in args)
            seg_kwargs = {k: segment_tensor(v, start, end, seq_len) for k, v in kwargs.items()}


            
            # Override with our computed fields
            seg_kwargs["attention_mask"] = seg_mask.to(seg_aug.dtype)
            if seg_pos_ids is not None:
                seg_kwargs["position_ids"] = seg_pos_ids
            seg_kwargs["use_cache"] = self.sliding_window
            
            if self.sliding_window:
                seg_kwargs["past_key_values"] = past_key_values
            else:
                # In non-sliding mode, ensure no cache is used by the underlying layer
                seg_kwargs.pop("layer_past", None)
                seg_kwargs.pop("cache_position", None)
                seg_kwargs.pop("past_key_values", None)
                seg_kwargs["use_cache"] = False

            if self._rotary_fn is not None and seg_pos_ids is not None:
                cos, sin = self._rotary_fn(seg_aug, seg_pos_ids)
                seg_kwargs["position_embeddings"] = (cos, sin)


            layer_out = self.layer(seg_aug, *seg_args, **seg_kwargs)
            if self.sliding_window:
                assert past_key_values is not None, "Past key values object must be provided"
                # In-place update & trim so outer references observe changes
                if os.environ.get("ARMT_DEBUG_SW"):
                    k = past_key_values.layers[self.info['layer']].keys
                    v = past_key_values.layers[self.info['layer']].values
                    print(f"[H-CACHE:pre] L{self.info['layer']} K={tuple(k.shape) if k is not None else None} V={tuple(v.shape) if v is not None else None}")
                past_key_values = self.update_past_key_values_sw(past_key_values, self.segment_size)
                if os.environ.get("ARMT_DEBUG_SW"):
                    k = past_key_values.layers[self.info['layer']].keys
                    v = past_key_values.layers[self.info['layer']].values
                    print(f"[H-CACHE:post] L{self.info['layer']} K={tuple(k.shape) if k is not None else None} V={tuple(v.shape) if v is not None else None}")
            if isinstance(layer_out, tuple):
                seg_out = layer_out[0]
            else:
                seg_out = layer_out

            seg_mem_out = seg_out[:, -self.num_mem_tokens:, :]
            W_mem, z, first_seg = self._update_mem_with_mem(
                seg_mem_out, W_mem, z, first_seg
            )
            first_seg = False

            out_full.append(seg_out)

            past_attn_mask = attn_mask
            seg_num += 1

        merged = torch.cat(out_full, dim=1)

        # Persist updated memory state for vertical mode to reuse across segments
        self.memory_state = (W_mem, z)

        if isinstance(layer_out, tuple):
            YELLOW = "\033[93m"
            if len(layer_out) == 1:
                return (merged,)
            elif len(layer_out) == 2:
                warnings.warn(f"{YELLOW}Last attention was not tested for horizontal forward{RESET}")
                return (merged, None)
            elif len(layer_out) == 3:
                warnings.warn(f"{YELLOW}Last attention and kv states were not tested for horizontal forward{RESET}")
                return (merged, None, present_kv)
            else:
                raise ValueError(f"Expected 1, 2 or 3 elements in layer output, got {len(layer_out)}")
        else:
            return merged

    def update_past_key_values_sw(self, past_key_values, window_size):
        """
        Update past key values for sliding window attention.
        This keeps only the most recent tokens within the window size.
        """
        if is_empty_past_key_values(past_key_values, self.info['layer']):
            return None
            
        # Convert to legacy cache format for easier manipulation
        if hasattr(past_key_values, 'to_legacy_cache'):
            legacy = past_key_values.to_legacy_cache()
            legacy = past_key_values.to_legacy_cache()
        
        # Keep only the most recent real tokens within the window size
        k, v = legacy[self.info['layer']]
        k = k[..., -window_size-self.num_mem_tokens:-self.num_mem_tokens, :]
        v = v[..., -window_size-self.num_mem_tokens:-self.num_mem_tokens, :]
        
        past_key_values.layers[self.info['layer']].keys = k
        past_key_values.layers[self.info['layer']].values = v
        return past_key_values


class InnerLoopARMTForCausalLM(PreTrainedModel):
    """
    Drop-in ARMT model that installs InnerLoopAssociativeLayerWrapper into a base
    HF Causal LM. All segmentation happens inside each wrapped layer; no outer
    recurrent driver is needed.
    """

    # Reuse the config used by the outer-loop variant for parity
    config_class = ARMTConfig

    def __init__(self, config: PretrainedConfig, **kwargs):
        global LIGER_KERNEL_AVAILABLE
        super().__init__(config, **kwargs)
        from transformers import AutoConfig, AutoModelForCausalLM

        # Resolve base model from either provided name or config
        base_model = None
        bm_cfg = getattr(config, "base_model_config", None)
        bm_name = getattr(config, "base_model_name", None)

        if 'llama' not in bm_name:
            LIGER_KERNEL_AVAILABLE = False
            os.environ["ARMT_DISABLE_LIGER_KERNEL"] = "1"
        if LIGER_KERNEL_AVAILABLE and not os.environ.get("ARMT_DISABLE_LIGER_KERNEL"):
            apply_liger_kernel_to_llama()

        if bm_cfg is not None and bm_name is not None:
            raise ValueError("Exactly one of `base_model_name` or `base_model_config` must be provided in config.")
        if bm_cfg is not None:
            if isinstance(bm_cfg, PretrainedConfig) and getattr(bm_cfg, "model_type", None) != getattr(config, "model_type", None):
                resolved_cfg = bm_cfg
            elif isinstance(bm_cfg, dict):
                from transformers import AutoConfig as HF_AutoConfig

                if "model_type" not in bm_cfg:
                    raise ValueError("`base_model_config` dict must include a 'model_type' key.")
                cfg_or_inst = HF_AutoConfig.for_model(bm_cfg["model_type"])  # type: ignore[arg-type]
                if isinstance(cfg_or_inst, PretrainedConfig):
                    resolved_cfg = cfg_or_inst
                    for k, v in bm_cfg.items():
                        setattr(resolved_cfg, k, v)
                else:
                    resolved_cfg = cfg_or_inst.from_dict(bm_cfg)
            elif isinstance(bm_cfg, str):
                from transformers import AutoConfig as HF_AutoConfig

                resolved_cfg = HF_AutoConfig.from_pretrained(bm_cfg)
            else:
                raise TypeError("`base_model_config` must be a transformers.PretrainedConfig, dict, or str.")
            base_model = AutoModelForCausalLM.from_config(resolved_cfg)
        elif bm_name is not None:
            from transformers import AutoModelForCausalLM as HF_AutoModelForCausalLM

            base_model = HF_AutoModelForCausalLM.from_pretrained(bm_name)
        else:
            raise ValueError("InnerLoopARMTForCausalLM requires either `base_model_config` or `base_model_name` in the config.")

        # Install wrappers
        self.model = base_model

        # Extract hyperparameters (fall back to sane defaults if missing)
        self.num_mem_tokens = int(getattr(config, "num_mem_tokens", 0) or 0)
        self.d_mem = int(getattr(config, "d_mem", 512))
        self.segment_size = int(getattr(config, "segment_size", 512))
        self.segment_alignment = getattr(config, "segment_alignment", "left")
        if self.segment_alignment != 'left':
            raise 
        self.layers_attr = getattr(config, "layers_attr", "model.layers")
        self.correction = bool(getattr(config, "correction", True))
        self.n_heads = int(getattr(config, "n_heads", 1))
        self.use_denom = bool(getattr(config, "use_denom", True))
        self.gating = bool(getattr(config, "gating", False))
        self.freeze_mem_flag = bool(getattr(config, "freeze_mem", False))
        self.use_sink = bool(getattr(config, "use_sink", False))
        self.sliding_window = bool(getattr(config, "sliding_window", False))

        # Shared trainable memory embeddings (used by all layers)
        emb = self.model.get_input_embeddings()
        d_model = emb.embedding_dim
        memory_dim = getattr(self.model.config, "n_embd", getattr(self.model.config, "hidden_size", d_model))
        # Robust std in float32 with sane fallback
        # with torch.no_grad():
        #     emb_std32 = emb.weight.detach().float().std()
        #     if not torch.isfinite(emb_std32):
        #         emb_std32 = torch.tensor(0.02, device=emb.weight.device)
        #     emb_std32 = torch.clamp(emb_std32, min=1e-3, max=0.1)
        memory_weights = torch.empty(
            (self.num_mem_tokens, memory_dim), device=emb.weight.device, dtype=emb.weight.dtype
        )
        # torch.nn.init.normal_(memory_weights, mean=0.0, std=emb_std32.to(memory_weights.dtype))
        torch.nn.init.normal_(memory_weights, mean=0.0, std=0.02)
        self.memory = nn.Parameter(memory_weights, requires_grad=True)
        if self.use_sink:
            self.sink = nn.Parameter(
                torch.randn((1, memory_dim), device=emb.weight.device, dtype=emb.weight.dtype), requires_grad=True
            )
        # function to access layers container
        def _get_layers_from_model(model_root: nn.Module):
            obj = model_root
            for attr in self.layers_attr.split("."):
                obj = getattr(obj, attr)
            return obj

        layers = _get_layers_from_model(self.model)
        rotary_fn = None
        if hasattr(self.model, "model") and hasattr(self.model.model, "rotary_emb"):
            rotary_fn = self.model.model.rotary_emb
        elif hasattr(self.model, "gpt_neox") and hasattr(self.model.gpt_neox, "rotary_emb"):
            rotary_fn = self.model.gpt_neox.rotary_emb

        for i in range(len(layers)):
            layers[i] = InnerLoopAssociativeLayerWrapper(
                layer=layers[i],
                d_model=d_model,
                num_mem_tokens=self.num_mem_tokens,
                d_mem=self.d_mem,
                segment_size=self.segment_size,
                n_heads=self.n_heads,
                correction=self.correction,
                use_denom=self.use_denom,
                gating=self.gating,
                use_sink=self.use_sink,
                sliding_window=self.sliding_window,
                get_memory_fn=lambda self_ref=self: self_ref.memory,
                get_sink_fn=lambda self_ref=self: getattr(self_ref, "sink", None),
                rotary_fn=rotary_fn,
                info={"layer": i},
            )

        if self.freeze_mem_flag:
            for layer in _get_layers_from_model(self.model):
                layer.freeze_mem()


        # Expose convenience accessor
        self.get_layers = lambda: _get_layers_from_model(self.model)

        self.vertical_mode = False

    # ----- control helpers -----
    def generate_mode(self, is_on: bool):
        for layer in self.get_layers():
            layer.generate_mode = is_on

    def zero_mem(self):
        """Reset memory state for all layers."""
        for layer in self.get_layers():
            layer.zero_mem()

    def detach_mem(self):
        """Detach memory state for all layers."""
        for layer in self.get_layers():
            layer.detach_mem()

    def augment_sequence(self, hidden_states: torch.Tensor, mem: torch.Tensor, sink: torch.Tensor = None):
        segments = torch.split(hidden_states, self.segment_size, dim=1)
        if sink is not None:
            augmented_segments = [torch.cat([sink.to(segment.dtype).to(segment.device), segment, mem.to(segment.dtype).to(segment.device)], dim=1) for segment in segments]
        else:
            augmented_segments = [torch.cat([segment, mem.to(segment.dtype).to(segment.device)], dim=1) for segment in segments]
        augmented_sequence = torch.cat(augmented_segments, dim=1)

        return augmented_sequence

    def clean_sequence(self, hidden_states: torch.Tensor):
        augmented_segments = torch.split(hidden_states, self.segment_size+self.num_mem_tokens+int(self.use_sink), dim=1)
        segments = [segment[:, int(self.use_sink):-self.num_mem_tokens] for segment in augmented_segments]
        return torch.cat(segments, dim=1)

    def augment_attention_mask(self, attention_mask: torch.Tensor):
        segments = torch.split(attention_mask, self.segment_size, dim=1)
        if self.use_sink:
            augmented_segments = [torch.cat([
                torch.ones(segment.shape[0], 1, device=segment.device, dtype=segment.dtype), 
                segment, 
                torch.ones(segment.shape[0], self.num_mem_tokens, device=segment.device, dtype=segment.dtype)
            ], dim=1) for segment in segments]
        else:
            augmented_segments = [torch.cat([
                segment, 
                torch.ones(segment.shape[0], self.num_mem_tokens, device=segment.device, dtype=segment.dtype)
            ], dim=1) for segment in segments]
        augmented_attention_mask = torch.cat(augmented_segments, dim=1)
        return augmented_attention_mask

    def augment_labels(self, labels):
        if labels is None:
            return None
        first = labels[:, :1]
        segments = torch.split(labels[:, 1:], self.segment_size, dim=1)
        if self.use_sink:
            augmented_segments = [torch.cat([
                -100 * torch.ones(segment.shape[0], 1, device=segment.device, dtype=segment.dtype),
                segment,
                -100 * torch.ones(segment.shape[0], self.num_mem_tokens, device=segment.device, dtype=segment.dtype)
            ], dim=1) for segment in segments]
        else:
            augmented_segments = [torch.cat([
                segment,
                -100 * torch.ones(segment.shape[0], self.num_mem_tokens, device=segment.device, dtype=segment.dtype)
            ], dim=1) for segment in segments]
        augmented_segments = torch.cat(augmented_segments, dim=1)
        augmented_labels = torch.cat([first, augmented_segments], dim=1)
        return augmented_labels

    def augment(self, input_ids, inputs_embeds, attention_mask, labels):
        if input_ids is not None:
            assert inputs_embeds is None, "input_ids and inputs_embeds cannot be provided together"
            hidden_states = self.model.get_input_embeddings()(input_ids)
        elif inputs_embeds is not None:
            hidden_states = inputs_embeds
        else:
            raise ValueError("Either input_ids or inputs_embeds must be provided")
        mem = self.memory.unsqueeze(0).expand(hidden_states.size(0), -1, -1)
        sink = self.sink.unsqueeze(0).expand(hidden_states.size(0), -1, -1) if self.use_sink else None

        augmented_hidden_states = self.augment_sequence(hidden_states, mem, sink)
        augmented_attention_mask = self.augment_attention_mask(attention_mask)
        augmented_labels = self.augment_labels(labels)
        return augmented_hidden_states, augmented_attention_mask, augmented_labels

    def forward(
        self,
        input_ids=None,
        labels=None,
        labels_mask=None,
        inputs_embeds=None,
        attention_mask=None,
        output_attentions=None,
        output_hidden_states=None,
        output_only_last_segment=False,
        num_items_in_batch=None,
        use_cache=None,
        past_key_values=None,
    ):  
        if labels_mask is not None:
            assert labels_mask.any(), "labels_mask must not be all zeros"
        # Apply labels_mask by mapping masked positions to -100 (ignored by loss)
        effective_labels = labels
        if labels is not None and labels_mask is not None:
            if isinstance(labels_mask, torch.Tensor):
                mask_bool = labels_mask.bool() if labels_mask.dtype != torch.bool else labels_mask
                effective_labels = labels.masked_fill(~mask_bool, -100)
            else:
                raise ValueError("labels_mask must be a torch.Tensor")

        if attention_mask is None:
            if input_ids is not None:
                attention_mask = torch.ones(input_ids.shape[0], input_ids.shape[1], device=input_ids.device, dtype=input_ids.dtype)
            else:
                attention_mask = torch.ones(inputs_embeds.shape[0], inputs_embeds.shape[1], device=inputs_embeds.device, dtype=inputs_embeds.dtype)
        
        if self.vertical_mode:
            return self.forward_vertical(
                input_ids=input_ids,
                labels=effective_labels,
                inputs_embeds=inputs_embeds,
                attention_mask=attention_mask,
                output_attentions=output_attentions,
                output_hidden_states=output_hidden_states, 
                output_only_last_segment=output_only_last_segment,
                num_items_in_batch=num_items_in_batch,
                use_cache=use_cache,
                past_key_values=past_key_values,
                past_attn_mask=None
        )
        else:
            return self.forward_horizontal(
                input_ids=input_ids,
                labels=effective_labels,
                inputs_embeds=inputs_embeds,
                attention_mask=attention_mask,
                output_attentions=output_attentions, 
                output_hidden_states=output_hidden_states, 
                output_only_last_segment=output_only_last_segment,
                num_items_in_batch=num_items_in_batch,
                use_cache=use_cache,
                past_key_values=past_key_values
            )
    def forward_vertical(
        self,
        input_ids=None,
        labels=None,
        inputs_embeds=None,
        attention_mask=None,
        output_attentions=None,
        output_hidden_states=None,
        output_only_last_segment=False,
        num_items_in_batch=None,
        use_cache=None,
        past_key_values=None,
        past_attn_mask=None,
    ):
        assert not self.training or os.environ.get("ARMT_DISABLE_LIGER_KERNEL"), "Liger kernel is not supported for training in vertical mode, to disable liger kernel, set ARMT_DISABLE_LIGER_KERNEL=1"
        # Establish batch/seq info
        if input_ids is not None:
            assert inputs_embeds is None
            B, L = input_ids.shape
            device = input_ids.device
        elif inputs_embeds is not None:
            B, L, _ = inputs_embeds.shape
            device = inputs_embeds.device
        else:
            raise ValueError("Either input_ids or inputs_embeds must be provided")
        dtype = next(self.model.parameters()).dtype

        augmented_hidden_states, augmented_attention_mask, augmented_labels = self.augment(input_ids, inputs_embeds, attention_mask, labels)

        # Helper to split tensors into segments
        def split_tensor(tensor: torch.Tensor, segment_size: int):
            return torch.split(tensor, segment_size+self.num_mem_tokens+int(self.use_sink), dim=1)

        # Build segmented inputs
        # Split all provided tensors consistently
        seg_inputs_embeds = split_tensor(augmented_hidden_states, self.segment_size)
        seg_attention_mask = split_tensor(augmented_attention_mask, self.segment_size) if attention_mask is not None else None
        seg_labels = split_tensor(augmented_labels, self.segment_size) if labels is not None else None
        # Assemble list of per-segment dicts
        num_segments = len(seg_inputs_embeds) 
        segments = []
        for i in range(num_segments):
            segments.append({
                "inputs_embeds": seg_inputs_embeds[i],
                "attention_mask": None if seg_attention_mask is None else seg_attention_mask[i],
                "labels": None if seg_labels is None else seg_labels[i],
            })

        # Sliding window state across segments
        use_sliding = bool(self.sliding_window)
        shared_cache = past_key_values if (use_sliding and past_key_values is not None) else (DynamicCache() if use_sliding else None)
        past_attn_mask = past_attn_mask if use_sliding else None
        # Absolute positions across segments
        pos_offset = 0

        # Run each segment through the base model; per-layer memory persists inside wrappers
        seg_outputs = []
        layers = self.get_layers()
        for seg in segments:
            seg_len = seg["inputs_embeds"].size(1)
            if seg.get("attention_mask") is None:
                base_2d = torch.ones(B, seg_len, device=device, dtype=dtype)
            else:
                base_2d = seg["attention_mask"]
            cur4d = attn_mask_to_4d(base_2d, upper=False, query_len=seg_len)
            cur4d = invert_attn_mask(cur4d, dtype=dtype)

            # Absolute position ids (match horizontal behavior when given position_ids=None)
            position_ids = torch.arange(pos_offset, pos_offset + seg_len, device=device).long().unsqueeze(0)

            # Temporarily wrap each layer to inject past_attn_mask into kwargs
            orig_forwards = [ly.forward for ly in layers]
            seg_past_attn_mask = past_attn_mask
            def _inject_mask(orig_fn, mask):
                def _wrapped(hs, *a, **k):
                    # Inject past attention mask and shared cache at layer level to mirror horizontal
                    if mask is not None:
                        if 'past_attn_mask' not in k:
                            k['past_attn_mask'] = mask
                        # Ensure using shared DynamicCache for this segment
                        if 'past_key_values' not in k or k['past_key_values'] is None:
                            k['past_key_values'] = shared_cache
                        # Guard against blocks that expect a tuple per layer
                        if hasattr(k['past_key_values'], 'layers') and len(k['past_key_values'].layers) < len(layers):
                            # Extend layers with empty entries up to current depth
                            needed = len(layers) - len(k['past_key_values'].layers)
                            k['past_key_values'].layers.extend([type(k['past_key_values'].layers[0])() for _ in range(needed)])
                        k['use_cache'] = True
                    return orig_fn(hs, *a, **k)
                return _wrapped
            for i, ly in enumerate(layers):
                ly.forward = _inject_mask(orig_forwards[i], seg_past_attn_mask)

            out = self.model(
                input_ids=seg.get("input_ids"),
                inputs_embeds=seg.get("inputs_embeds"),
                attention_mask=cur4d,
                position_ids=position_ids,
                output_attentions=output_attentions,
                output_hidden_states=output_hidden_states,
                use_cache=use_sliding,
                past_key_values=shared_cache if use_sliding else None,
            )
            if os.environ.get("ARMT_DEBUG_SW"):
                print(f"[V-SEG] seg_len={seg_len} cur4d={tuple(cur4d.shape)} pos=({int(position_ids[0,0])},{int(position_ids[0,-1])})")
                if hasattr(out, 'past_key_values') and out.past_key_values is not None:
                    try:
                        k = out.past_key_values.layers[0].keys
                        v = out.past_key_values.layers[0].values
                        print(f"[V-CACHE:out] L0 K={tuple(k.shape) if k is not None else None} V={tuple(v.shape) if v is not None else None}")
                    except Exception:
                        pass
            # Restore original forwards
            for i, ly in enumerate(layers):
                ly.forward = orig_forwards[i]
            seg_outputs.append(out)

            if use_sliding:
                # Update cache and past attention for next segment
                shared_cache = out.past_key_values if hasattr(out, 'past_key_values') else shared_cache
                if os.environ.get("ARMT_DEBUG_SW") and shared_cache is not None:
                    try:
                        k = shared_cache.layers[0].keys
                        v = shared_cache.layers[0].values
                        print(f"[V-CACHE:posttrim] L0 K={tuple(k.shape) if k is not None else None} V={tuple(v.shape) if v is not None else None}")
                    except Exception:
                        pass
                past_attn_mask = cur4d[:, :, int(self.use_sink):-self.num_mem_tokens, int(self.use_sink):-self.num_mem_tokens]
            pos_offset += seg_len

        # Aggregate outputs across segments
        # Concatenate logits along time dimension
        full_logits = torch.cat([o.logits for o in seg_outputs], dim=1) if len(seg_outputs) > 1 else seg_outputs[0].logits

        result = {}
        result["logits"] = self.clean_sequence(full_logits)

        # Compute loss similar to outer wrapper
        if labels is not None:
            labels = labels[:, -full_logits.size(1):]
            shift_labels = labels[..., 1:].contiguous()
            flat_labels = shift_labels.view(-1)

            if labels_mask is not None:
                labels_mask = labels_mask[:, -full_logits.size(1):]
                shift_mask = labels_mask[..., :-1].contiguous()
            else:
                shift_mask = None

            shift_logits = full_logits[..., :-1, :].contiguous()
            flat_logits = shift_logits.view(-1, shift_logits.size(-1))
            if shift_mask is not None:
                flat_logits = flat_logits[shift_mask.view(-1)]
                flat_labels = flat_labels[shift_mask.view(-1)]
            loss_fct = CrossEntropyLoss(reduction='sum')
            loss = loss_fct(flat_logits, flat_labels)

            if labels_mask is not None:
                denom = labels_mask[..., :-1].contiguous().view(-1).sum()
            else:
                denom = (flat_labels != -100).sum()
            denom = torch.clamp(denom, min=1)
            result["loss"] = loss / denom
        
        if output_hidden_states:
            if all(getattr(o, 'hidden_states', None) is not None for o in seg_outputs):
                # Concatenate last layer hidden states across segments per layer index
                full_hidden_states = tuple([
                    torch.cat(layer_hs, dim=1)
                    for layer_hs in zip(*[o.hidden_states for o in seg_outputs])
                ])
                result["hidden_states"] = full_hidden_states

        return result
    
    # ----- hf api -----
    def forward_horizontal(
        self,
        input_ids=None,
        labels=None,
        inputs_embeds=None,
        attention_mask=None,
        output_attentions=None,
        output_hidden_states=None,
        output_only_last_segment=False,
        num_items_in_batch=None,
        use_cache=None,
        past_key_values=None,
    ):
        augmented_hidden_states, augmented_attention_mask, augmented_labels = self.augment(input_ids, inputs_embeds, attention_mask, labels)
        out = self.model(
            labels=augmented_labels,
            inputs_embeds=augmented_hidden_states,
            attention_mask=augmented_attention_mask,
            output_attentions=output_attentions,
            output_hidden_states=output_hidden_states,
            use_cache=use_cache,
            past_key_values=past_key_values,
        )
        if not LIGER_KERNEL_AVAILABLE:
            out.logits = self.clean_sequence(out.logits)
        self.zero_mem()
        return out

    def generate(self, input_ids, attention_mask=None, **generate_kwargs):
        """
        Generate tokens using the inner-loop model with proper sliding window attention.
        This method should produce the same logits as the forward method for alignment.
        """

        warnings.warn("Efficient generation is not implemented")
        if self.sliding_window:
            return self._generate_inefficient(input_ids, attention_mask, **generate_kwargs)
        else:
            # return self._generate_standard(input_ids, attention_mask, **generate_kwargs) 
            return self._generate_inefficient(input_ids, attention_mask, **generate_kwargs)
            # raise NotImplementedError("Non-sliding window generation is not implemented")
    
    def _generate_standard(self, input_ids, attention_mask=None, **generate_kwargs):
        """Standard generation without sliding window."""
        generate_kwargs['output_scores'] = generate_kwargs.get('return_logits', False)
        generate_kwargs['return_dict_in_generate'] = generate_kwargs.get('return_logits', False)
        generate_kwargs.pop('return_logits')
        out = self.model.generate(input_ids=input_ids, attention_mask=attention_mask, **generate_kwargs)
        if generate_kwargs.get('output_scores', False):
            print(out.scores)
            return out.sequences, out.scores
        else:
            return out.sequences
    
    def _generate_inefficient(self, input_ids, attention_mask=None, **generate_kwargs):
        """
        Generate tokens using sliding window attention that matches the forward method.
        This ensures alignment between generate and forward methods.
        INEFFICIENT: recomputes the entire sequence on every token generation.
        Kept for reference and testing purposes.
        """
        max_new_tokens = generate_kwargs.get('max_new_tokens', 1)
        eos_token_id = generate_kwargs.get('eos_token_id', None)
        return_logits = generate_kwargs.get('return_logits', False)
        
        generated_ids = None
        all_logits = []

        # Process tokens one by one to ensure perfect alignment
        for i in range(max_new_tokens):
            # Prepare the full sequence for this step
            if generated_ids is not None:
                current_input_ids = torch.cat([input_ids, generated_ids], dim=-1)
                current_attention_mask = torch.cat([attention_mask, torch.ones_like(generated_ids)], dim=-1)
            else:
                current_input_ids = input_ids
                current_attention_mask = attention_mask
            
            # Process the full sequence through the inner loop
            # Reset memory state before each forward pass to ensure complete independence
            self.zero_mem()
            
            with torch.no_grad():
                outputs = self.forward(
                    input_ids=current_input_ids,
                    attention_mask=current_attention_mask
                )
                next_token_logits = outputs.logits[:, -1, :]
            
            # Get next token
            next_token_id = torch.argmax(next_token_logits, dim=-1).unsqueeze(-1)
            
            if generated_ids is not None:
                generated_ids = torch.cat([generated_ids, next_token_id], dim=-1)
            else:
                generated_ids = next_token_id
            
            # Store the logits that were actually used to generate the next token
            if return_logits:
                all_logits.append(next_token_logits)
            
            # Check for EOS
            if eos_token_id is not None and (next_token_id == eos_token_id).all():
                break
        
        if return_logits:
            # Return the logits that were actually used for generation during the loop
            return generated_ids, torch.stack(all_logits, dim=1)
        else:
            return generated_ids

    def _generate_sliding_window(self, input_ids, attention_mask=None, **generate_kwargs):
        """
        Generate tokens using sliding window attention with efficient caching.
        Uses the base model directly with past_key_values to avoid recomputing the entire sequence.
        This method should produce the same logits as the forward method for alignment.
        """
        self.generate_mode(True)
        try:
            max_new_tokens = generate_kwargs.get('max_new_tokens', 1)
            eos_token_id = generate_kwargs.get('eos_token_id', None)
            return_logits = generate_kwargs.get('return_logits', False)
            
            # Initialize memory state
            self.zero_mem()
            
            # Process the input sequence through inner loop to get memory state
            if attention_mask is None:
                attention_mask = torch.ones_like(input_ids)
            
            # Get initial outputs using forward method (without caching for now)
            initial_outputs = self.forward(
                input_ids=input_ids,
                attention_mask=attention_mask
            )
            
            # Extract last logits
            next_token_logits = initial_outputs.logits[:, -1, :]
            
            generated_ids = None
            all_logits = []
            
            # Now implement truly efficient generation using past_key_values
            # First, we need to get the base model's past_key_values from the initial forward pass
            # But since our inner loop doesn't return past_key_values, we need a different approach
            
            base_model = self.model
            window_size = self.segment_size + self.num_mem_tokens + int(self.use_sink)
            
            # Let me try to use the base model directly with the initial sequence to get past_key_values
            try:
                # Get past_key_values from base model for the initial sequence
                base_outputs = base_model(
                    input_ids=input_ids,
                    attention_mask=attention_mask,
                    use_cache=True
                )
                past_key_values = base_outputs.past_key_values
                
                # Now we can use efficient generation
                for i in range(max_new_tokens):
                    # Get next token
                    next_token_id = torch.argmax(next_token_logits, dim=-1).unsqueeze(-1)
                    
                    if generated_ids is not None:
                        generated_ids = torch.cat([generated_ids, next_token_id], dim=-1)
                    else:
                        generated_ids = next_token_id
                    
                    # Store logits if requested
                    if return_logits:
                        all_logits.append(next_token_logits)
                    
                    # Check for EOS
                    if eos_token_id is not None and (next_token_id == eos_token_id).all():
                        break
                    
                    # Use efficient generation with past_key_values
                    with torch.no_grad():
                        next_outputs = base_model(
                            input_ids=next_token_id,
                            attention_mask=torch.ones_like(next_token_id),
                            past_key_values=past_key_values,
                            use_cache=True
                        )
                        next_token_logits = next_outputs.logits[:, -1, :]
                        past_key_values = next_outputs.past_key_values
                        
                        # Update past_key_values for sliding window
                        if past_key_values is not None:
                            past_key_values = self.update_past_key_values_sw(past_key_values, window_size)
                            
            except Exception as e:
                # If this fails, we need to understand why
                print(f"Error implementing efficient generation: {e}")
                print("This suggests the base model doesn't support the expected interface")
                print("Why could this happen?")
                print("1. The base model might not support past_key_values")
                print("2. The attention mask handling might be incompatible")
                print("3. The memory tokens might interfere with caching")
                print("4. The inner loop wrapper might not be compatible with base model caching")
                raise RuntimeError(f"Efficient generation failed: {e}")
            
            if return_logits:
                return generated_ids, torch.stack(all_logits, dim=1)
            else:
                return generated_ids
        finally:
            self.generate_mode(False)

    def load_state_dict(self, state_dict, strict: bool = True, assign: bool = False):
        try:
            return super().load_state_dict(state_dict, strict, assign)
        except RuntimeError:
            # Fallback: some checkpoints may target only the wrapped model
            self.model.load_state_dict(state_dict, strict=True)
            return

    def zero_mem(self):
        for layer in self.get_layers():
            layer.zero_mem()

    def detach_mem(self):
        for layer in self.get_layers():
            layer.detach_mem()

    def freeze_mem(self):
        for layer in self.get_layers():
            layer.freeze_mem()