Computes the total size of instances in a Tensor over the whole dataset.

x A Tensor, SparseTensor, or RaggedTensor.
reduce_instance_dims By default collapses the batch and instance dimensions to arrive at a single scalar output. If False, only collapses the batch dimension and outputs a vector of the same shape as the input.
name (Optional) A name for this operation.

A Tensor of type int64.