public int AccessSequential(int pos)
{
// DONE: Convert this into a permutation index using the golynski large perm. scheme
long n = this.Count;
for (int i = 0; i < this.sigma; ++i) {
if (this.xl_bitmap.Access (i * n + pos)) {
return i;
}
}
throw new ArgumentOutOfRangeException ();
}