gemma.cpp/util/convert_weights.py

76 lines
3.0 KiB
Python

# WIP - DO NOT MERGE
from collections import defaultdict
import torch
from gemma import config
from gemma import model as gemma_model
import numpy as np
TRANSFORMATIONS = defaultdict(lambda: lambda x: x, {
"embedder.weight": lambda x: np.concatenate([np.zeros([128, 2048]), x], 0),
"self_attn.qkv_proj.weight": lambda x: x,
"mlp.up_proj.weight" : lambda x: x,
"mlp.down_proj.weight" : lambda x: x,
})
def param_names():
"""Return parameter names in the order they are expected for deserialization."""
# note *weight_scaler params are ignored in the forward computation unless
# quantization is being used.
#
# since we are working with the full precision weights as input, don't
# include these in the parameters being iterated over.
# fmt: off
names = [
"embedder.weight", # embedder_input_embedding (vocab=256000, model_dim=2048) -> (vocab=256128, model_dim=2048)
"model.norm.weight" # final_norm_scale (model_dim=2048)
]
layer_params = [
# TODO(austinvhuang): transpositions here ...
"self_attn.qkv_proj.weight", # attn_vec_einsum_w (2560, 2048) -> (heads=8, model_dim=2048, qkv_dim=256)
"self_attn.o_proj.weight", # qkv_einsum_w (2048, 2048) -> (heads=8, qkv=3, qkv_dim=256, model_dim=2048)
# these are the same without any change
"mlp.gate_proj.weight", # gating_einsum_w (16384, 2048) => (gate/up=2, hidden=16384, model_dim=2048)
"mlp.up_proj.weight",
"mlp.down_proj.weight", # linear_w (2048, 16384) => (model_dim=2048, hidden=16384)
"input_layernorm.weight", # pre_attention_norm_scale (model_dim=2048)
"post_attention_layernorm.weight", # pre_ffw_norm_scale (model_dim=2048)
]
# fmt: on
for layer in range(18):
for layer_param in layer_params:
names = names + [f"model.layers.{layer}.{layer_param}"]
return names
def convert_weights():
# TODO(austinvhuang): parameterize paths
output_file = "2bit-f32.sbs"
model_config = config.get_model_config("2b")
model_config.dtype = "float32"
model_config.quant = "store_true"
model_config.tokenizer = "models/tokenizer.spm"
device = torch.device("cpu")
torch.set_default_dtype(torch.float)
model = gemma_model.GemmaForCausalLM(model_config)
model.load_weights("models/gemma-2b-it.ckpt")
model_dict = dict(model.named_parameters())
param_order = param_names()
print("Writing parameters ...")
with open(output_file, "wb") as bin_handle:
for name in param_order:
arr = model_dict[name].detach().numpy()
arr = TRANSFORMATIONS[name](arr)
# TODO(austinvhuang): reshapes
print(f" {name : <60}{str(arr.shape)}")
arr.flatten().astype(np.float32).tofile(bin_handle)
if __name__ == "__main__":
convert_weights()
print("Done")