# tf.keras.mixed_precision.set_global_policy

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| [![](https://www.tensorflow.org/images/GitHub-Mark-32px.png) View source on GitHub](https://github.com/keras-team/keras/tree/v2.14.0/keras/mixed_precision/policy.py#L383-L446) |

Sets the global dtype policy.

    tf.keras.mixed_precision.set_global_policy(
        policy
    )

The global policy is the default [`tf.keras.mixed_precision.Policy`](https://www.tensorflow.org/versions/r2.14/api_docs/python/tf/keras/mixed_precision/Policy) used for
layers, if no policy is passed to the layer constructor.

    tf.keras.mixed_precision.set_global_policy('mixed_float16')
    tf.keras.mixed_precision.global_policy()
    <Policy "mixed_float16">
    tf.keras.layers.Dense(10).dtype_policy
    <Policy "mixed_float16">
    # Global policy is not used if a policy
    # is directly passed to constructor
    tf.keras.layers.Dense(10, dtype='float64').dtype_policy
    <Policy "float64">
    tf.keras.mixed_precision.set_global_policy('float32')

If no global policy is set, layers will instead default to a Policy
constructed from [`tf.keras.backend.floatx()`](https://www.tensorflow.org/versions/r2.14/api_docs/python/tf/keras/backend/floatx).

To use mixed precision, the global policy should be set to `'mixed_float16'`
or `'mixed_bfloat16'`, so that every layer uses a 16-bit compute dtype and
float32 variable dtype by default.

Only floating point policies can be set as the global policy, such as
`'float32'` and `'mixed_float16'`. Non-floating point policies such as
`'int32'` and `'complex64'` cannot be set as the global policy because most
layers do not support such policies.

See [`tf.keras.mixed_precision.Policy`](https://www.tensorflow.org/versions/r2.14/api_docs/python/tf/keras/mixed_precision/Policy) for more information.

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| ## Args ||
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| `policy` | A Policy, or a string that will be converted to a Policy. Can also be None, in which case the global policy will be constructed from [`tf.keras.backend.floatx()`](https://www.tensorflow.org/versions/r2.14/api_docs/python/tf/keras/backend/floatx) |

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