while (pof2 < comm_size) pof2 <<= 1;
if (pof2 == comm_size && is_block_regular) {
/* noncommutative, pof2 size, and block regular */
while (pof2 < comm_size) pof2 <<= 1;
if (pof2 == comm_size && is_block_regular) {
/* noncommutative, pof2 size, and block regular */