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import os |
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from typing import Dict, Optional, Union |
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import numpy as np |
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import mlx.core as mx |
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from safetensors import numpy, safe_open |
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def save(tensors: Dict[str, mx.array], 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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tensors (`Dict[str, mx.array]`): |
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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.mlx import save |
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import mlx.core as mx |
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tensors = {"embedding": mx.zeros((512, 1024)), "attention": mx.zeros((256, 256))} |
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byte_data = save(tensors) |
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``` |
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""" |
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np_tensors = _mx2np(tensors) |
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return numpy.save(np_tensors, metadata=metadata) |
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def save_file( |
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tensors: Dict[str, mx.array], |
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filename: Union[str, os.PathLike], |
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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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tensors (`Dict[str, mx.array]`): |
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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.mlx import save_file |
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import mlx.core as mx |
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tensors = {"embedding": mx.zeros((512, 1024)), "attention": mx.zeros((256, 256))} |
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save_file(tensors, "model.safetensors") |
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``` |
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""" |
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np_tensors = _mx2np(tensors) |
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return numpy.save_file(np_tensors, filename, metadata=metadata) |
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def load(data: bytes) -> Dict[str, mx.array]: |
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""" |
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Loads a safetensors file into MLX 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, mx.array]`: dictionary that contains name as key, value as `mx.array` |
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Example: |
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```python |
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from safetensors.mlx 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 = numpy.load(data) |
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return _np2mx(flat) |
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def load_file(filename: Union[str, os.PathLike]) -> Dict[str, mx.array]: |
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""" |
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Loads a safetensors file into MLX 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, mx.array]`: dictionary that contains name as key, value as `mx.array` |
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Example: |
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```python |
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from safetensors.flax 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="mlx") 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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def _np2mx(numpy_dict: Dict[str, np.ndarray]) -> Dict[str, mx.array]: |
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for k, v in numpy_dict.items(): |
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numpy_dict[k] = mx.array(v) |
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return numpy_dict |
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def _mx2np(mx_dict: Dict[str, mx.array]) -> Dict[str, np.array]: |
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new_dict = {} |
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for k, v in mx_dict.items(): |
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new_dict[k] = np.asarray(v) |
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return new_dict |
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