| from typing import Optional |
|
|
| import torch |
| import torch.nn.functional as F |
|
|
| from diffusers.models.attention_processor import Attention |
| from ftfy import apply_plan |
|
|
|
|
| class NAGWanAttnProcessor2_0: |
| def __init__(self, nag_scale=1.0, nag_tau=2.5, nag_alpha=0.25): |
| if not hasattr(F, "scaled_dot_product_attention"): |
| raise ImportError("WanAttnProcessor2_0 requires PyTorch 2.0. To use it, please upgrade PyTorch to 2.0.") |
| self.nag_scale = nag_scale |
| self.nag_tau = nag_tau |
| self.nag_alpha = nag_alpha |
|
|
| def __call__( |
| self, |
| attn: Attention, |
| hidden_states: torch.Tensor, |
| encoder_hidden_states: Optional[torch.Tensor] = None, |
| attention_mask: Optional[torch.Tensor] = None, |
| rotary_emb: Optional[torch.Tensor] = None, |
| ) -> torch.Tensor: |
| apply_guidance = self.nag_scale > 1 and encoder_hidden_states is not None |
| if apply_guidance: |
| if len(encoder_hidden_states) == 2 * len(hidden_states): |
| batch_size = len(hidden_states) |
| else: |
| apply_guidance = False |
|
|
| encoder_hidden_states_img = None |
| if attn.add_k_proj is not None: |
| encoder_hidden_states_img = encoder_hidden_states[:, :257] |
| encoder_hidden_states = encoder_hidden_states[:, 257:] |
| if apply_guidance: |
| encoder_hidden_states_img = encoder_hidden_states_img[:batch_size] |
| if encoder_hidden_states is None: |
| encoder_hidden_states = hidden_states |
|
|
| query = attn.to_q(hidden_states) |
| key = attn.to_k(encoder_hidden_states) |
| value = attn.to_v(encoder_hidden_states) |
|
|
| if attn.norm_q is not None: |
| query = attn.norm_q(query) |
| if attn.norm_k is not None: |
| key = attn.norm_k(key) |
|
|
| query = query.unflatten(2, (attn.heads, -1)).transpose(1, 2) |
| key = key.unflatten(2, (attn.heads, -1)).transpose(1, 2) |
| value = value.unflatten(2, (attn.heads, -1)).transpose(1, 2) |
|
|
| if rotary_emb is not None: |
|
|
| def apply_rotary_emb(hidden_states: torch.Tensor, freqs: torch.Tensor): |
| x_rotated = torch.view_as_complex(hidden_states.to(torch.float64).unflatten(3, (-1, 2))) |
| x_out = torch.view_as_real(x_rotated * freqs).flatten(3, 4) |
| return x_out.type_as(hidden_states) |
|
|
| query = apply_rotary_emb(query, rotary_emb) |
| key = apply_rotary_emb(key, rotary_emb) |
|
|
| |
| hidden_states_img = None |
| if encoder_hidden_states_img is not None: |
| key_img = attn.add_k_proj(encoder_hidden_states_img) |
| key_img = attn.norm_added_k(key_img) |
| value_img = attn.add_v_proj(encoder_hidden_states_img) |
|
|
| key_img = key_img.unflatten(2, (attn.heads, -1)).transpose(1, 2) |
| value_img = value_img.unflatten(2, (attn.heads, -1)).transpose(1, 2) |
|
|
| hidden_states_img = F.scaled_dot_product_attention( |
| query, key_img, value_img, attn_mask=None, dropout_p=0.0, is_causal=False |
| ) |
| hidden_states_img = hidden_states_img.transpose(1, 2).flatten(2, 3) |
| hidden_states_img = hidden_states_img.type_as(query) |
|
|
| if apply_guidance: |
| key, key_negative = torch.chunk(key, 2, dim=0) |
| value, value_negative = torch.chunk(value, 2, dim=0) |
| hidden_states = F.scaled_dot_product_attention( |
| query, key, value, attn_mask=attention_mask, dropout_p=0.0, is_causal=False |
| ) |
| hidden_states = hidden_states.transpose(1, 2).flatten(2, 3) |
| hidden_states = hidden_states.type_as(query) |
| if apply_guidance: |
| hidden_states_negative = F.scaled_dot_product_attention( |
| query, key_negative, value_negative, attn_mask=attention_mask, dropout_p=0.0, is_causal=False |
| ) |
| hidden_states_negative = hidden_states_negative.transpose(1, 2).flatten(2, 3) |
| hidden_states_negative = hidden_states_negative.type_as(query) |
|
|
| hidden_states_positive = hidden_states |
|
|
| hidden_states_guidance = hidden_states_positive * self.nag_scale - hidden_states_negative * (self.nag_scale - 1) |
| norm_positive = torch.norm(hidden_states_positive, p=1, dim=-1, keepdim=True).expand(*hidden_states_positive.shape) |
| norm_guidance = torch.norm(hidden_states_guidance, p=1, dim=-1, keepdim=True).expand(*hidden_states_guidance.shape) |
|
|
| scale = norm_guidance / norm_positive |
| scale = torch.nan_to_num(scale, 10) |
| hidden_states_guidance[scale > self.nag_tau] = \ |
| hidden_states_guidance[scale > self.nag_tau] / (norm_guidance[scale > self.nag_tau] + 1e-7) * norm_positive[scale > self.nag_tau] * self.nag_tau |
|
|
| hidden_states = hidden_states_guidance * self.nag_alpha + hidden_states_positive * (1 - self.nag_alpha) |
|
|
| if hidden_states_img is not None: |
| hidden_states = hidden_states + hidden_states_img |
|
|
| hidden_states = attn.to_out[0](hidden_states) |
| hidden_states = attn.to_out[1](hidden_states) |
| return hidden_states |
|
|
