description: A class wrapping information needed by a distribute function.

tf.distribute.experimental.ValueContext

A class wrapping information needed by a distribute function.

tf.distribute.experimental.ValueContext(
    replica_id_in_sync_group=0, num_replicas_in_sync=1
)

This is a context class that is passed to the value_fn in strategy.experimental_distribute_values_from_function and contains information about the compute replicas. The num_replicas_in_sync and replica_id can be used to customize the value on each replica.

Example usage:

  1. Directly constructed.
>>> def value_fn(context):
...   return context.replica_id_in_sync_group/context.num_replicas_in_sync
>>> context = tf.distribute.experimental.ValueContext(
...   replica_id_in_sync_group=2, num_replicas_in_sync=4)
>>> per_replica_value = value_fn(context)
>>> per_replica_value
0.5
  1. Passed in by experimental_distribute_values_from_function.
>>> strategy = tf.distribute.MirroredStrategy(["GPU:0", "GPU:1"])
>>> def value_fn(value_context):
...   return value_context.num_replicas_in_sync
>>> distributed_values = (
...      strategy.experimental_distribute_values_from_function(
...        value_fn))
>>> local_result = strategy.experimental_local_results(distributed_values)
>>> local_result
(2, 2)

Args

replica_id_in_sync_group the current replica_id, should be an int in [0,num_replicas_in_sync).
num_replicas_in_sync the number of replicas that are in sync.

Attributes

num_replicas_in_sync Returns the number of compute replicas in sync.
replica_id_in_sync_group Returns the replica ID.