Function dense_to_sparse

tensorflow/contrib/layers/python/layers/layers.py:1551–1572

Converts a dense tensor into a sparse tensor. 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

(tensor, eos_token=0, outputs_collections=None, scope=None)

@add_arg_scope
def dense_to_sparse(tensor, eos_token=0, outputs_collections=None, scope=None):
  """Converts a dense tensor into a sparse tensor.

  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.
  """
  with variable_scope.variable_scope(scope, 'dense_to_sparse', [tensor]) as sc:
    tensor = ops.convert_to_tensor(tensor)
    indices = array_ops.where(
        math_ops.not_equal(tensor, constant_op.constant(eos_token,
                                                        tensor.dtype)))
    values = array_ops.gather_nd(tensor, indices)
    shape = array_ops.shape(tensor, out_type=dtypes.int64)
    outputs = sparse_tensor.SparseTensor(indices, values, shape)
    return utils.collect_named_outputs(outputs_collections, sc.name, outputs)


@add_arg_scope