Spaces:
Running
on
Zero
Running
on
Zero
File size: 6,973 Bytes
62c110b |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 |
# coding=utf-8
# Copyright 2024 The HuggingFace Inc. team.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""PyTorch - Flax general utilities."""
from pickle import UnpicklingError
import jax
import jax.numpy as jnp
import numpy as np
from flax.serialization import from_bytes
from flax.traverse_util import flatten_dict
from ..utils import logging
logger = logging.get_logger(__name__)
#####################
# Flax => PyTorch #
#####################
# from https://github.com/huggingface/transformers/blob/main/src/transformers/modeling_flax_pytorch_utils.py#L224-L352
def load_flax_checkpoint_in_pytorch_model(pt_model, model_file):
try:
with open(model_file, "rb") as flax_state_f:
flax_state = from_bytes(None, flax_state_f.read())
except UnpicklingError as e:
try:
with open(model_file) as f:
if f.read().startswith("version"):
raise OSError(
"You seem to have cloned a repository without having git-lfs installed. Please"
" install git-lfs and run `git lfs install` followed by `git lfs pull` in the"
" folder you cloned."
)
else:
raise ValueError from e
except (UnicodeDecodeError, ValueError):
raise EnvironmentError(f"Unable to convert {model_file} to Flax deserializable object. ")
return load_flax_weights_in_pytorch_model(pt_model, flax_state)
def load_flax_weights_in_pytorch_model(pt_model, flax_state):
"""Load flax checkpoints in a PyTorch model"""
try:
import torch # noqa: F401
except ImportError:
logger.error(
"Loading Flax weights in PyTorch requires both PyTorch and Flax to be installed. Please see"
" https://pytorch.org/ and https://flax.readthedocs.io/en/latest/installation.html for installation"
" instructions."
)
raise
# check if we have bf16 weights
is_type_bf16 = flatten_dict(jax.tree_util.tree_map(lambda x: x.dtype == jnp.bfloat16, flax_state)).values()
if any(is_type_bf16):
# convert all weights to fp32 if they are bf16 since torch.from_numpy can-not handle bf16
# and bf16 is not fully supported in PT yet.
logger.warning(
"Found ``bfloat16`` weights in Flax model. Casting all ``bfloat16`` weights to ``float32`` "
"before loading those in PyTorch model."
)
flax_state = jax.tree_util.tree_map(
lambda params: params.astype(np.float32) if params.dtype == jnp.bfloat16 else params, flax_state
)
pt_model.base_model_prefix = ""
flax_state_dict = flatten_dict(flax_state, sep=".")
pt_model_dict = pt_model.state_dict()
# keep track of unexpected & missing keys
unexpected_keys = []
missing_keys = set(pt_model_dict.keys())
for flax_key_tuple, flax_tensor in flax_state_dict.items():
flax_key_tuple_array = flax_key_tuple.split(".")
if flax_key_tuple_array[-1] == "kernel" and flax_tensor.ndim == 4:
flax_key_tuple_array = flax_key_tuple_array[:-1] + ["weight"]
flax_tensor = jnp.transpose(flax_tensor, (3, 2, 0, 1))
elif flax_key_tuple_array[-1] == "kernel":
flax_key_tuple_array = flax_key_tuple_array[:-1] + ["weight"]
flax_tensor = flax_tensor.T
elif flax_key_tuple_array[-1] == "scale":
flax_key_tuple_array = flax_key_tuple_array[:-1] + ["weight"]
if "time_embedding" not in flax_key_tuple_array:
for i, flax_key_tuple_string in enumerate(flax_key_tuple_array):
flax_key_tuple_array[i] = (
flax_key_tuple_string.replace("_0", ".0")
.replace("_1", ".1")
.replace("_2", ".2")
.replace("_3", ".3")
.replace("_4", ".4")
.replace("_5", ".5")
.replace("_6", ".6")
.replace("_7", ".7")
.replace("_8", ".8")
.replace("_9", ".9")
)
flax_key = ".".join(flax_key_tuple_array)
if flax_key in pt_model_dict:
if flax_tensor.shape != pt_model_dict[flax_key].shape:
raise ValueError(
f"Flax checkpoint seems to be incorrect. Weight {flax_key_tuple} was expected "
f"to be of shape {pt_model_dict[flax_key].shape}, but is {flax_tensor.shape}."
)
else:
# add weight to pytorch dict
flax_tensor = np.asarray(flax_tensor) if not isinstance(flax_tensor, np.ndarray) else flax_tensor
pt_model_dict[flax_key] = torch.from_numpy(flax_tensor)
# remove from missing keys
missing_keys.remove(flax_key)
else:
# weight is not expected by PyTorch model
unexpected_keys.append(flax_key)
pt_model.load_state_dict(pt_model_dict)
# re-transform missing_keys to list
missing_keys = list(missing_keys)
if len(unexpected_keys) > 0:
logger.warning(
"Some weights of the Flax model were not used when initializing the PyTorch model"
f" {pt_model.__class__.__name__}: {unexpected_keys}\n- This IS expected if you are initializing"
f" {pt_model.__class__.__name__} from a Flax model trained on another task or with another architecture"
" (e.g. initializing a BertForSequenceClassification model from a FlaxBertForPreTraining model).\n- This"
f" IS NOT expected if you are initializing {pt_model.__class__.__name__} from a Flax model that you expect"
" to be exactly identical (e.g. initializing a BertForSequenceClassification model from a"
" FlaxBertForSequenceClassification model)."
)
if len(missing_keys) > 0:
logger.warning(
f"Some weights of {pt_model.__class__.__name__} were not initialized from the Flax model and are newly"
f" initialized: {missing_keys}\nYou should probably TRAIN this model on a down-stream task to be able to"
" use it for predictions and inference."
)
return pt_model
|