[numerics] add a comment to warn about the fact that NSM_extract_block is working only if the csc storage is well ordered
@@ -889,6 +889,8 @@ void NSM_extract_block(NumericsMatrix* M, double* blockM, size_t pos_row, size_t
for(CS_INT p = Mp[j]; p < Mp[j+1]; ++p)
{
CS_INT row_nb = Mi[p];
+ /* Warning : the following strategy work only if the csc storage is
+ correclty ordered. Use NSM_fix_csc to be sure*/
if(row_nb >= (CS_INT) pos_row)
{
if(row_nb >= (CS_INT)(pos_row + block_row_size))
