tf.parallel_stack( values, name='parallel_stack' )
See the guide: Tensor Transformations > Slicing and Joining
Stacks a list of rank-
R tensors into one rank-
(R+1) tensor in parallel.
Requires that the shape of inputs be known at graph construction time.
Packs the list of tensors in
values into a tensor with rank one higher than each tensor in
values, by packing them along the first dimension. Given a list of length
N of tensors of shape
(A, B, C); the
output tensor will have the shape
(N, A, B, C).
x = tf.constant([1, 4]) y = tf.constant([2, 5]) z = tf.constant([3, 6]) tf.parallel_stack([x, y, z]) # [[1, 4], [2, 5], [3, 6]]
The difference between
parallel_stack is that
stack requires all the inputs be computed before the operation will begin but doesn't require that the input shapes be known during graph construction.
parallel_stack will copy pieces of the input into the output as they become available, in some situations this can provide a performance benefit.
parallel_stack does NOT support backpropagation.
This is the opposite of unstack. The numpy equivalent is
tf.parallel_stack([x, y, z]) = np.asarray([x, y, z])
values: A list of
Tensorobjects with the same shape and type.
name: A name for this operation (optional).
output: A stacked
Tensorwith the same type as
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Code samples licensed under the Apache 2.0 License.