Convert an ordered subset of k integers from the set [0, ..., n - 1] to its encoding as an integers in [0, n choose k) in lexicographic order. This is the inverse of PetscDTEnumSubset.
Input Arguments
n
- a non-negative integer (see note about limits below)
k
- an integer in [0, n]
subset
- an ordered subset of the integers [0, ..., n - 1]
Output Arguments
index -the rank of the subset in lexicographic order
Note: this is limited by arguments such that n choose k can be represented by PetscInt