fuse_idx_int64 Function

private elemental function fuse_idx_int64(p, q, n_dim, fortran) result(pq)

Fuse p, q into one contiguous index

If fortran is true, then this assumes columnwise Fortran order, i.e. the index looks like this:

1 5 2 6 3 7 4 8

Otherwise it is C-order, i.e. row major (but still one-indexed).

Note

Note that this function does preserve lexicographical ordering, if fortran == .false.. If (p_1, q_1) <= (p_2, q_2) fuse_idx(p_1, q_1, n_dim, fortran=.false.) <= fuse_idx(p_2, q_2, fortran=.false.). @endote

Arguments

Type IntentOptional Attributes Name
integer(kind=int64), intent(in) :: p

2d-array indices
integer(kind=int64), intent(in) :: q

2d-array indices
integer(kind=int64), intent(in) :: n_dim

number of rows for Fortran (column-major), number of columns for C (row-major).
logical, intent(in) :: fortran

Use column major order

Return Value integer(kind=int64)

contiguous 1d-array index