Sets the global dtype policy.

Used in the notebooks

Used in the guide Used in the tutorials

The global policy is the default tf.keras.mixed_precision.Policy used for layers, if no policy is passed to the layer constructor.

<Policy "mixed_float16">
<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">

If no global policy is set, layers will instead default to a Policy constructed from 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 for more information.

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()