tf.nn.sampled_softmax_loss(weights, biases, labels, inputs, num_sampled, num_classes, num_true=1, sampled_values=None, remove_accidental_hits=True, partition_strategy='mod', name='sampled_softmax_loss')

tf.nn.sampled_softmax_loss(weights, biases, labels, inputs, num_sampled, num_classes, num_true=1, sampled_values=None, remove_accidental_hits=True, partition_strategy='mod', name='sampled_softmax_loss')

See the guide: Neural Network > Candidate Sampling

Computes and returns the sampled softmax training loss.

This is a faster way to train a softmax classifier over a huge number of classes.

This operation is for training only. It is generally an underestimate of the full softmax loss.

At inference time, you can compute full softmax probabilities with the expression tf.nn.softmax(tf.matmul(inputs, tf.transpose(weights)) + biases).

See our Candidate Sampling Algorithms Reference

Also see Section 3 of Jean et al., 2014 (pdf) for the math.

Args:

  • weights: A Tensor of shape [num_classes, dim], or a list of Tensor objects whose concatenation along dimension 0 has shape [num_classes, dim]. The (possibly-sharded) class embeddings.
  • biases: A Tensor of shape [num_classes]. The class biases.
  • labels: A Tensor of type int64 and shape [batch_size, num_true]. The target classes. Note that this format differs from the labels argument of nn.softmax_cross_entropy_with_logits.
  • inputs: A Tensor of shape [batch_size, dim]. The forward activations of the input network.
  • num_sampled: An int. The number of classes to randomly sample per batch.
  • num_classes: An int. The number of possible classes.
  • num_true: An int. The number of target classes per training example.
  • sampled_values: a tuple of (sampled_candidates, true_expected_count, sampled_expected_count) returned by a *_candidate_sampler function. (if None, we default to log_uniform_candidate_sampler)
  • remove_accidental_hits: A bool. whether to remove "accidental hits" where a sampled class equals one of the target classes. Default is True.
  • partition_strategy: A string specifying the partitioning strategy, relevant if len(weights) > 1. Currently "div" and "mod" are supported. Default is "mod". See tf.nn.embedding_lookup for more details.
  • name: A name for the operation (optional).

Returns:

A batch_size 1-D tensor of per-example sampled softmax losses.

Defined in tensorflow/python/ops/nn_impl.py.