Fix description of tocsc in csr_matrix
@@ -102,7 +102,8 @@ class csr_matrix(compressed._compressed_sparse_matrix):
Args:
copy (bool): If ``False``, it shares data arrays as much as
- possible.
+ possible. Actually this option is ignored because all
+ arrays in a matrix cannot be shared in csr to csc conversion.
Returns:
cupy.sparse.csc_matrix: Converted matrix.
