.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "beginner/basics/saveloadrun_tutorial.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        Click :ref:`here <sphx_glr_download_beginner_basics_saveloadrun_tutorial.py>`
        to download the full example code

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_beginner_basics_saveloadrun_tutorial.py:


`基础知识 <intro.html>`_ ||
`快速入门 <quickstart_tutorial.html>`_ ||
`张量 <tensorqs_tutorial.html>`_ ||
`数据集与数据加载器 <data_tutorial.html>`_ ||
`Transforms <transforms_tutorial.html>`_ ||
`构建神经网络 <buildmodel_tutorial.html>`_ ||
`自动微分 <autogradqs_tutorial.html>`_ ||
`优化模型参数 <optimization_tutorial.html>`_ ||
**保存和加载模型**

保存和加载模型
============================

在本节中，我们将学习如何通过保存、加载以及运行模型预测，来持久化模型。

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.. code-block:: default


    import torch
    import torchvision.models as models



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保存和加载模型权重
--------------------------------
PyTorch模型将学习到的参数存储在一个内部状态字典中，称为``state_dict``。这些参数可以通过``torch.save``进行持久化。
方法:

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.. code-block:: default


    model = models.vgg16(weights='IMAGENET1K_V1')
    torch.save(model.state_dict(), 'model_weights.pth')


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要加载模型权重，您需要先创建一个相同模型的实例，然后使用``load_state_dict()``方法加载参数。

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.. code-block:: default


    model = models.vgg16() # we do not specify ``weights``, i.e. create untrained model
    model.load_state_dict(torch.load('model_weights.pth'))
    model.eval()


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。。 注意:: 在进行推理之前，请确保调用``model.eval()``方法以将 dropout 和 batch normalization layers设置为评估模式。如果不这样做，将导致不一致的推理结果。

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保存和加载带有结构的模型
-------------------------------------
在加载模型权重时，我们需要先实例化模型类，因为类定义了网络的结构。我们可能希望将这个类的结构与模型一起保存，
在这种情况下，我们可以将``model``（而不是``model.state_dict()``）传递给 save 函数：

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.. code-block:: default


    torch.save(model, 'model.pth')


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我们可以使用如下方式加载模型: 

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.. code-block:: default


    model = torch.load('model.pth')


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.. 注意:: 这种方法在序列化模型时使用 Python 的 `pickle <https://docs.python.org/3/library/pickle.html>`_模块，因此在加载模型时需要依赖实际的类定义。

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相关教程
-----------------
- `PyTorch 中保存和加载通用Checkpoint <https://pytorch.org/tutorials/recipes/recipes/saving_and_loading_a_general_checkpoint.html>`_
- `从 checkpoint 加载 nn.Module 的实用技巧 <https://pytorch.org/tutorials/recipes/recipes/module_load_state_dict_tips.html?highlight=loading%20nn%20module%20from%20checkpoint>`_


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   **Total running time of the script:** ( 0 minutes  0.000 seconds)


.. _sphx_glr_download_beginner_basics_saveloadrun_tutorial.py:

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  .. container:: sphx-glr-footer sphx-glr-footer-example


    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: saveloadrun_tutorial.py <saveloadrun_tutorial.py>`

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: saveloadrun_tutorial.ipynb <saveloadrun_tutorial.ipynb>`


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 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_