torch.Tensor.crow_indices
Tensor.crow_indices() -> IntTensor
Returns the tensor containing the compressed row indices of the
   "self" tensor when "self" is a sparse CSR tensor of layout
   "sparse_csr". The "crow_indices" tensor is strictly of shape
   ("self".size(0) + 1) and of type "int32" or "int64". When using MKL
   routines such as sparse matrix multiplication, it is necessary to
   use "int32" indexing in order to avoid downcasting and potentially
   losing information.
Example::
      >>> csr = torch.eye(5,5).to_sparse_csr()
      >>> csr.crow_indices()
      tensor([0, 1, 2, 3, 4, 5], dtype=torch.int32)