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# Copyright (c) 2023, Tri Dao. | |
import math | |
import json | |
import re | |
from pathlib import Path | |
from collections import OrderedDict | |
import torch | |
import torch.nn.functional as F | |
from einops import rearrange | |
from transformers import GPT2Config, AutoConfig, PretrainedConfig | |
def remap_state_dict_hf_btlm(state_dict, config): | |
# Word embedding and position embedding | |
def key_mapping_pos_emb(key): | |
return re.sub(r"^transformer.wpe.", "transformer.embeddings.position_embeddings.", key) | |
if "transformer.wpe.weight" in state_dict: | |
state_dict = OrderedDict((key_mapping_pos_emb(k), v) for k, v in state_dict.items()) | |
word_embeddings = state_dict.pop("transformer.wte.weight") | |
# It's possible that vocab_size is padded to be a multiple of 8, for example. | |
pad_vocab_size_multiple = getattr(config, "pad_vocab_size_multiple", 1) | |
vocab_size = math.ceil(config.vocab_size / pad_vocab_size_multiple) * pad_vocab_size_multiple | |
state_dict["transformer.embeddings.word_embeddings.weight"] = F.pad( | |
word_embeddings, (0, 0, 0, vocab_size - word_embeddings.shape[0]) | |
) | |
state_dict["lm_head.weight"] = state_dict["transformer.embeddings.word_embeddings.weight"] | |
# LayerNorm | |
def key_mapping_ln(key): | |
key = re.sub(r"^transformer.ln_f.(weight|bias)", r"transformer.ln_f.\1", key) | |
key = re.sub(r"^transformer.h.(\d+).ln_(1|2).(weight|bias)", r"transformer.layers.\1.norm\2.\3", key) | |
return key | |
state_dict = OrderedDict((key_mapping_ln(k), v) for k, v in state_dict.items()) | |
# MLP | |
for d in range(config.num_hidden_layers): | |
W1 = state_dict.pop(f"transformer.h.{d}.mlp.c_fc.weight") | |
W3 = state_dict.pop(f"transformer.h.{d}.mlp.c_fc2.weight") | |
state_dict[f"transformer.layers.{d}.mlp.fc1.weight"] = torch.cat([W1.t(), W3.t()], dim=0) | |
b1 = state_dict.pop(f"transformer.h.{d}.mlp.c_fc.bias") | |
b3 = state_dict.pop(f"transformer.h.{d}.mlp.c_fc2.bias") | |
state_dict[f"transformer.layers.{d}.mlp.fc1.bias"] = torch.cat([b1, b3], dim=0) | |
W2 = state_dict.pop(f"transformer.h.{d}.mlp.c_proj.weight") | |
state_dict[f"transformer.layers.{d}.mlp.fc2.weight"] = W2.t() | |
def key_mapping_mlp(key): | |
key = re.sub(r"^transformer.h.(\d+).mlp.c_proj.bias", r"transformer.layers.\1.mlp.fc2.bias", key) | |
return key | |
state_dict = OrderedDict((key_mapping_mlp(k), v) for k, v in state_dict.items()) | |
# Attention | |
for d in range(config.num_hidden_layers): | |
Wqkv = state_dict.pop(f"transformer.h.{d}.attn.c_attn.weight") | |
state_dict[f"transformer.layers.{d}.mixer.Wqkv.weight"] = Wqkv.t() | |
Wout = state_dict.pop(f"transformer.h.{d}.attn.c_proj.weight") | |
state_dict[f"transformer.layers.{d}.mixer.out_proj.weight"] = Wout.t() | |
state_dict.pop(f"transformer.relative_pe.slopes") # We don't store the Alibi slopes | |
def key_mapping_attn(key): | |
key = re.sub(r"^transformer.h.(\d+).attn.c_attn.bias", r"transformer.layers.\1.mixer.Wqkv.bias", key) | |
key = re.sub( | |
r"^transformer.h.(\d+).attn.c_proj.bias", r"transformer.layers.\1.mixer.out_proj.bias", key | |
) | |
return key | |
state_dict = OrderedDict((key_mapping_attn(k), v) for k, v in state_dict.items()) | |
return state_dict | |
def btlm_config_to_gpt2_config(btlm_config: PretrainedConfig) -> GPT2Config: | |
return GPT2Config( | |
vocab_size=btlm_config.vocab_size, | |
n_positions=0 if btlm_config.position_embedding_type == "alibi" else btlm_config.n_positions, | |
n_embd=btlm_config.hidden_size, | |
n_layer=btlm_config.num_hidden_layers, | |
n_head=btlm_config.num_attention_heads, | |
n_inner=btlm_config.n_inner, | |
activation_function=btlm_config.activation_function, | |
resid_pdrop=btlm_config.resid_pdrop, | |
embd_pdrop=btlm_config.embd_pdrop, | |
attn_pdrop=btlm_config.attn_pdrop, | |
layer_norm_epsilon=btlm_config.layer_norm_epsilon, | |
initializer_range=btlm_config.initializer_range, | |
bos_token_id=btlm_config.bos_token_id, | |
eos_token_id=btlm_config.eos_token_id, | |
# These are new arguments not in the original GPT2Config | |
use_alibi=btlm_config.position_embedding_type == "alibi", | |
use_flash_attn=btlm_config.position_embedding_type == "alibi", # Alibi code path requires flash_attn | |
mup_width_scale=btlm_config.mup_width_scale, | |
mup_embeddings_multiplier=btlm_config.mup_embeddings_scale, | |
mup_output_multiplier=btlm_config.mup_output_alpha, | |
mup_scale_qk_dot_by_d=btlm_config.mup_scale_qk_dot_by_d, | |
mlp_multiple_of=1, | |
) | |