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Samples a set of classes using a log-uniform (Zipfian) base distribution.
tf.random.log_uniform_candidate_sampler(
true_classes,
num_true,
num_sampled,
unique,
range_max,
seed=None,
name=None
)
This operation randomly samples a tensor of sampled classes
(sampled_candidates
) from the range of integers [0, range_max)
.
The elements of sampled_candidates
are drawn without replacement
(if unique=True
) or with replacement (if unique=False
) from
the base distribution.
The base distribution for this operation is an approximately log-uniform or Zipfian distribution:
P(class) = (log(class + 2) - log(class + 1)) / log(range_max + 1)
This sampler is useful when the target classes approximately follow such a distribution - for example, if the classes represent words in a lexicon sorted in decreasing order of frequency. If your classes are not ordered by decreasing frequency, do not use this op.
In addition, this operation returns tensors true_expected_count
and sampled_expected_count
representing the number of times each
of the target classes (true_classes
) and the sampled
classes (sampled_candidates
) is expected to occur in an average
tensor of sampled classes. These values correspond to Q(y|x)
defined in this
document.
If unique=True
, then these are post-rejection probabilities and we
compute them approximately.