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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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