!
!
!    Fortran kernel for sparse matrix-vector product in the AIJ/CRL format
!
#include <petsc/finclude/petscsys.h>
!
pure subroutine FortranMultCRL(m,rmax,x,y,icols,acols)
  implicit none (type, external)
  PetscInt, intent(in) :: m,rmax,icols(m,rmax)
  PetscScalar, intent(in) :: x(0:m-1), acols(m,rmax)
  PetscScalar, intent(out) :: y(m)

  PetscInt    i,j

  do j=1,m
    y(j) = acols(j,1)*x(icols(j,1))
  end do

  do i=2,rmax
    do j=1,m
      y(j) = y(j) + acols(j,i)*x(icols(j,i))
    end do
  end do
end subroutine FortranMultCRL