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Indicates how a distributed variable will be aggregated.
tf.distribute.Strategy
distributes a model by making multiple copies
(called "replicas") acting data-parallel on different elements of the input
batch. When performing some variable-update operation, say
var.assign_add(x)
, in a model, we need to resolve how to combine the
different values for x
computed in the different replicas.
NONE
: This is the default, giving an error if you use a variable-update operation with multiple replicas.SUM
: Add the updates across replicas.MEAN
: Take the arithmetic mean ("average") of the updates across replicas.ONLY_FIRST_REPLICA
: This is for when every replica is performing the same update, but we only want to perform the update once. Used, e.g., for the global step counter.ONLY_FIRST_TOWER
: Deprecated alias forONLY_FIRST_REPLICA
.
Class Variables | |
---|---|
MEAN |
<VariableAggregation.MEAN: 2>
|
NONE |
<VariableAggregation.NONE: 0>
|
ONLY_FIRST_REPLICA |
<VariableAggregation.ONLY_FIRST_REPLICA: 3>
|
SUM |
<VariableAggregation.SUM: 1>
|