tf.gather

tf.gather(
    params,
    indices,
    validate_indices=None,
    name=None,
    axis=0
)

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

See the guides: Tensor Transformations > Slicing and Joining, Variables > Sparse Variable Updates

Gather slices from params axis axis according to indices.

indices must be an integer tensor of any dimension (usually 0-D or 1-D). Produces an output tensor with shape params.shape[:axis] + indices.shape + params.shape[axis + 1:] where:

# Scalar indices (output is rank(params) - 1).
output[a_0, ..., a_n, b_0, ..., b_n] =
  params[a_0, ..., a_n, indices, b_0, ..., b_n]

# Vector indices (output is rank(params)).
output[a_0, ..., a_n, i, b_0, ..., b_n] =
  params[a_0, ..., a_n, indices[i], b_0, ..., b_n]

# Higher rank indices (output is rank(params) + rank(indices) - 1).
output[a_0, ..., a_n, i, ..., j, b_0, ... b_n] =
  params[a_0, ..., a_n, indices[i, ..., j], b_0, ..., b_n]

Note that on CPU, if an out of bound index is found, an error is returned. On GPU, if an out of bound index is found, a 0 is stored in the corresponding output value.

Args:

• params: A Tensor. The tensor from which to gather values. Must be at least rank axis + 1.
• indices: A Tensor. Must be one of the following types: int32, int64. Index tensor. Must be in range [0, params.shape[axis]).
• axis: A Tensor. Must be one of the following types: int32, int64. The axis in params to gather indices from. Defaults to the first dimension. Supports negative indexes.
• name: A name for the operation (optional).

Returns:

A Tensor. Has the same type as params.