| n | - a non-negative integer (see note about limits below) | |
| k | - an integer in [0, n] | |
| j | - an index in [0, n choose k) |
| perm | - the jth subset of size k of the integers [0, ..., n - 1], followed by its complementary set. | |
| isOdd | - if not NULL, return whether perm is an even or odd permutation. |
Note: this is limited by arguments such that n choose k can be represented by PetscInt