tf.contrib.layers.dense_to_sparse

Converts a dense tensor into a sparse tensor.

tf.contrib.layers.dense_to_sparse(
    tensor, eos_token=0, outputs_collections=None, scope=None
)

An example use would be to convert dense labels to sparse ones so that they can be fed to the ctc_loss.

Args
tensor	An int Tensor to be converted to a Sparse.
eos_token	An integer. It is part of the target label that signifies the end of a sentence.
outputs_collections	Collection to add the outputs.
scope	Optional scope for name_scope.