Support TPUStrategy in the mixed precision API.

This is done by creating a dynamic subclass of AutoCastVariable when it wraps a DistributedVariable subclass. Now, when wrapping a variable that subclasses from DistributedVariable, a dynamic class subclassing both AutoCastVariable and variable.__class__ is created. That way, the AutoCastVariable will still pass isinstance(auto_cast_variable, variable.__class__) checks. This allows AutoCastVariables to work with TPUStrategy, which extensively uses isinstance.

Alternatives considered:
1. Remove all isinstance checks of distributed values from distribution strategy. This is difficult, and people could add isinstance checks in the future.

2. Adding a metaclass to DistributedValues, and overriding __instancecheck__. Or using an ABCMeta metaclass to register a custom subclass. The issue is using metaclasses is complicated and I'd rather avoid it.

3. Using a variable_creator_scope with a lowered priority to have DistributedVariable wrap AutoCastVariables, instead of having AutoCastVariables wrap DistributedVariables. This requires modifications to DistributedVariables and requires the user a private TF API in Keras, so I did not go with this approach.

PiperOrigin-RevId: 271237386
5 files changed
tree: 35d3bbddf9aa96c17f8caf095a673fef4b11b7d2
  1. .github/
  2. tensorflow/
  3. third_party/
  4. tools/
  5. .bazelrc
  6. .gitignore
  7. ACKNOWLEDGMENTS
  8. ADOPTERS.md
  9. arm_compiler.BUILD
  10. AUTHORS
  11. BUILD
  12. CODE_OF_CONDUCT.md
  13. CODEOWNERS
  14. configure
  15. configure.cmd
  16. configure.py
  17. CONTRIBUTING.md
  18. ISSUE_TEMPLATE.md
  19. ISSUES.md
  20. LICENSE
  21. models.BUILD
  22. README.md
  23. RELEASE.md
  24. SECURITY.md
  25. WORKSPACE
README.md
Documentation
Documentation

TensorFlow is an end-to-end open source platform for machine learning. It has a comprehensive, flexible ecosystem of tools, libraries, and community resources that lets researchers push the state-of-the-art in ML and developers easily build and deploy ML powered applications.

TensorFlow was originally developed by researchers and engineers working on the Google Brain team within Google's Machine Intelligence Research organization for the purposes of conducting machine learning and deep neural networks research. The system is general enough to be applicable in a wide variety of other domains, as well.

TensorFlow provides stable Python and C++ APIs, as well as non-guaranteed backwards compatible API for other languages.

Keep up-to-date with release announcements and security updates by subscribing to announce@tensorflow.org. See all the mailing lists.

Install

See the TensorFlow install guide for the pip package, to enable GPU support, use a Docker container, and build from source.

To install the current release for CPU-only:

$ pip install tensorflow

Use the GPU package for CUDA-enabled GPU cards:

$ pip install tensorflow-gpu

Nightly binaries are available for testing using the tf-nightly and tf-nightly-gpu packages on PyPi.

Try your first TensorFlow program

$ python
>>> import tensorflow as tf
>>> tf.enable_eager_execution()
>>> tf.add(1, 2).numpy()
3
>>> hello = tf.constant('Hello, TensorFlow!')
>>> hello.numpy()
'Hello, TensorFlow!'

For more examples, see the TensorFlow tutorials.

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If you want to contribute to TensorFlow, be sure to review the contribution guidelines. This project adheres to TensorFlow's code of conduct. By participating, you are expected to uphold this code.

We use GitHub issues for tracking requests and bugs, please see TensorFlow Discuss for general questions and discussion, and please direct specific questions to Stack Overflow.

The TensorFlow project strives to abide by generally accepted best practices in open-source software development:

CII Best Practices Contributor Covenant

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Learn more about the TensorFlow community and how to contribute.

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Apache License 2.0