xref: /petsc/src/mat/impls/aij/seq/crl/ftn-kernels/fmultcrl.F90 (revision edb0e59d3c097acd4a4005a4e51d4daa5c739255)
1!
2!
3!    Fortran kernel for sparse matrix-vector product in the AIJ/CRL format
4!
5#include <petsc/finclude/petscsys.h>
6!
7pure subroutine FortranMultCRL(m, rmax, x, y, icols, acols)
8  use, intrinsic :: ISO_C_binding
9  implicit none(type, external)
10  PetscInt, intent(in) :: m, rmax, icols(m, rmax)
11  PetscScalar, intent(in) :: x(0:m - 1), acols(m, rmax)
12  PetscScalar, intent(out) :: y(m)
13
14  PetscInt :: i
15
16  y(1:m) = acols(1:m, 1)*x(icols(1:m, 1))
17  do i = 2, rmax
18    y(1:m) = y(1:m) + acols(1:m, i)*x(icols(1:m, i))
19  end do
20end subroutine FortranMultCRL
21