tf.VariableSynchronization

Indicates when a distributed variable will be synced.

• AUTO: Indicates that the synchronization will be determined by the current DistributionStrategy (eg. With MirroredStrategy this would be ON_WRITE).
• NONE: Indicates that there will only be one copy of the variable, so there is no need to sync.
• ON_WRITE: Indicates that the variable will be updated across devices every time it is written.

• ON_READ: Indicates that the variable will be aggregated across devices when it is read (eg. when checkpointing or when evaluating an op that uses the variable).

  Example:

>>> temp_grad=[tf.Variable([0.], trainable=False,
...                      synchronization=tf.VariableSynchronization.ON_READ,
...                      aggregation=tf.VariableAggregation.MEAN
...                      )]