size_t m, size_t k, size_t n,
size_t Block_size, size_t group, size_t key,
size_t size_row, size_t size_col, size_t NB_groups ){
- double *a, *b, *c, *res;
+ double *a, *b, *c;
+ double *res = NULL;
/* Split the communicator into groups */
/* Find out my identity in the default communicator */