add doc

Author: rusty1s

torch_sparse/spmm.py

@@ -8,10 +8,13 @@ def spmm(index: Tensor, value: Tensor, m: int, n: int,
 
  Args:
  index (:class:`LongTensor`): The index tensor of sparse matrix.
- value (:class:`Tensor`): The value tensor of sparse matrix.
+ value (:class:`Tensor`): The value tensor of sparse matrix, either of
+ floating-point or integer type. Does not work for boolean and
+ complex number data types.
  m (int): The first dimension of sparse matrix.
  n (int): The second dimension of sparse matrix.
- matrix (:class:`Tensor`): The dense matrix.
+ matrix (:class:`Tensor`): The dense matrix of same type as
+ :obj:`value`.
 
  :rtype: :class:`Tensor`
  """