tf.contrib.metrics.set_union(a, b, validate_indices=True)
Compute set union of elements in last dimension of a and b.
All but the last dimension of a and b must match.
Args:
a: Tensor or SparseTensor of the same type as b. If sparse, indices must be sorted in row-major order.
b: Tensor or SparseTensor of the same type as a. Must be SparseTensor if a is SparseTensor. If sparse, indices must be sorted in row-major order.
validate_indices: Whether to validate the order and range of sparse indi