mhla/gpt1900-d34-physicssft-expanded

GPT-1900 D34 Physics CLM Expanded

3.29B parameter GPT-1900 with continued pretraining on pre-1900 + post-1900 physics texts (Rutherford, Thomson, Lorentz, Planck).

Model Details

• Architecture: Custom GPT with RoPE, QK-norm, ReLU², value embeddings (ResFormer), per-layer residual/skip scalars
• Parameters: 3.29B
• Layers: 34
• Hidden dim: 2176
• Attention heads: 17 (query) / 17 (kv)
• Head dim: 128
• Context length: 2048 tokens
• Vocab size: 32,768 (BPE, GPT-4 style split pattern)
• Training: Physics CLM (expanded, 10 epochs), from base d34-22btok

Checkpoint Contents

model_014400.pt          # Model weights
meta_014400.json         # Training config and metadata
tokenizer/                   # BPE tokenizer (tiktoken format) + token byte counts
nanochat/                    # Source code to load and run the model

Quick Start

import torch, json
from nanochat.gpt import GPT, GPTConfig
from nanochat.tokenizer import RustBPETokenizer

tokenizer = RustBPETokenizer.from_directory("tokenizer")

with open("meta_014400.json") as f:
    meta = json.load(f)

config = GPTConfig(**meta["model_config"])

with torch.device("meta"):
    model = GPT(config)
model.to_empty(device="cuda")
model.init_weights()

state_dict = torch.load("model_014400.pt", map_location="cuda")
state_dict = {k.removeprefix("_orig_mod."): v for k, v in state_dict.items()}
model.load_state_dict(state_dict, strict=True, assign=True)
model.eval()

bos = tokenizer.get_bos_token_id()
tokens = tokenizer.encode("It was a dark and stormy night", prepend=bos)
with torch.amp.autocast(device_type="cuda", dtype=torch.bfloat16):
    for token in model.generate(tokens, max_tokens=100, temperature=0.8):
        print(tokenizer.decode([token]), end="", flush=True)

Dependencies

torch>=2.9
tiktoken
rustbpe