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
       

2. 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.