// read column-by-column, aka column_major
int mapping[] = { 0, 11, 21, 31, 12, 22, 32, 42, 23, 33, 43, 53, 34, 44, 54, 0, 45, 55, 0, 0, 56, 0, 0, 0 };
return mapping[ index ];
}
// read column-by-column, aka column_major
int mapping[] = { 0, 11, 21, 31, 12, 22, 32, 42, 23, 33, 43, 53, 34, 44, 54, 0, 45, 55, 0, 0, 56, 0, 0, 0 };
return mapping[ index ];
}