177 lines
4.8 KiB
Python
177 lines
4.8 KiB
Python
import os
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import sys
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from typing import Dict, Optional, Union
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import numpy as np
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from safetensors import deserialize, safe_open, serialize, serialize_file
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def _tobytes(tensor: np.ndarray) -> bytes:
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if not _is_little_endian(tensor):
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tensor = tensor.byteswap(inplace=False)
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return tensor.tobytes()
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def save(tensor_dict: Dict[str, np.ndarray], metadata: Optional[Dict[str, str]] = None) -> bytes:
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"""
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Saves a dictionary of tensors into raw bytes in safetensors format.
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Args:
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tensor_dict (`Dict[str, np.ndarray]`):
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The incoming tensors. Tensors need to be contiguous and dense.
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metadata (`Dict[str, str]`, *optional*, defaults to `None`):
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Optional text only metadata you might want to save in your header.
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For instance it can be useful to specify more about the underlying
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tensors. This is purely informative and does not affect tensor loading.
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Returns:
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`bytes`: The raw bytes representing the format
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Example:
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```python
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from safetensors.numpy import save
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import numpy as np
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tensors = {"embedding": np.zeros((512, 1024)), "attention": np.zeros((256, 256))}
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byte_data = save(tensors)
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```
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"""
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flattened = {k: {"dtype": v.dtype.name, "shape": v.shape, "data": _tobytes(v)} for k, v in tensor_dict.items()}
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serialized = serialize(flattened, metadata=metadata)
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result = bytes(serialized)
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return result
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def save_file(
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tensor_dict: Dict[str, np.ndarray], filename: Union[str, os.PathLike], metadata: Optional[Dict[str, str]] = None
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) -> None:
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"""
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Saves a dictionary of tensors into raw bytes in safetensors format.
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Args:
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tensor_dict (`Dict[str, np.ndarray]`):
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The incoming tensors. Tensors need to be contiguous and dense.
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filename (`str`, or `os.PathLike`)):
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The filename we're saving into.
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metadata (`Dict[str, str]`, *optional*, defaults to `None`):
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Optional text only metadata you might want to save in your header.
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For instance it can be useful to specify more about the underlying
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tensors. This is purely informative and does not affect tensor loading.
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Returns:
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`None`
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Example:
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```python
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from safetensors.numpy import save_file
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import numpy as np
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tensors = {"embedding": np.zeros((512, 1024)), "attention": np.zeros((256, 256))}
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save_file(tensors, "model.safetensors")
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```
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"""
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flattened = {k: {"dtype": v.dtype.name, "shape": v.shape, "data": _tobytes(v)} for k, v in tensor_dict.items()}
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serialize_file(flattened, filename, metadata=metadata)
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def load(data: bytes) -> Dict[str, np.ndarray]:
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"""
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Loads a safetensors file into numpy format from pure bytes.
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Args:
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data (`bytes`):
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The content of a safetensors file
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Returns:
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`Dict[str, np.ndarray]`: dictionary that contains name as key, value as `np.ndarray` on cpu
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Example:
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```python
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from safetensors.numpy import load
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file_path = "./my_folder/bert.safetensors"
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with open(file_path, "rb") as f:
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data = f.read()
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loaded = load(data)
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```
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"""
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flat = deserialize(data)
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return _view2np(flat)
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def load_file(filename: Union[str, os.PathLike]) -> Dict[str, np.ndarray]:
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"""
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Loads a safetensors file into numpy format.
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Args:
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filename (`str`, or `os.PathLike`)):
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The name of the file which contains the tensors
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Returns:
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`Dict[str, np.ndarray]`: dictionary that contains name as key, value as `np.ndarray`
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Example:
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```python
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from safetensors.numpy import load_file
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file_path = "./my_folder/bert.safetensors"
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loaded = load_file(file_path)
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```
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"""
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result = {}
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with safe_open(filename, framework="np") as f:
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for k in f.keys():
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result[k] = f.get_tensor(k)
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return result
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_TYPES = {
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"F64": np.float64,
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"F32": np.float32,
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"F16": np.float16,
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"I64": np.int64,
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"U64": np.uint64,
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"I32": np.int32,
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"U32": np.uint32,
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"I16": np.int16,
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"U16": np.uint16,
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"I8": np.int8,
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"U8": np.uint8,
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"BOOL": bool,
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}
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def _getdtype(dtype_str: str) -> np.dtype:
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return _TYPES[dtype_str]
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def _view2np(safeview) -> Dict[str, np.ndarray]:
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result = {}
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for k, v in safeview:
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dtype = _getdtype(v["dtype"])
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arr = np.frombuffer(v["data"], dtype=dtype).reshape(v["shape"])
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result[k] = arr
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return result
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def _is_little_endian(tensor: np.ndarray) -> bool:
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byteorder = tensor.dtype.byteorder
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if byteorder == "=":
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if sys.byteorder == "little":
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return True
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else:
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return False
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elif byteorder == "|":
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return True
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elif byteorder == "<":
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return True
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elif byteorder == ">":
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return False
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raise ValueError(f"Unexpected byte order {byteorder}")
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