1! 2! 3! Fortran kernel for sparse matrix-vector product in the AIJ matrix format 4! 5#include <petsc/finclude/petscsys.h> 6! 7pure subroutine FortranMultTransposeAddAIJ(n,x,ii,jj,a,y) 8 use, intrinsic :: ISO_C_binding 9 implicit none (type, external) 10 PetscScalar, intent(in) :: x(0:*),a(0:*) 11 PetscScalar, intent(inout) :: y(0:*) 12 PetscInt, intent(in) :: n,ii(*),jj(0:*) 13 14 PetscInt :: i,jstart,jend 15 16 jend = ii(1) 17 do i=1,n 18 jstart = jend 19 jend = ii(i+1) 20 y(jj(jstart:jend-1)) = y(jj(jstart:jend-1)) + x(i-1)*a(jstart:jend-1) 21 end do 22end subroutine FortranMultTransposeAddAIJ 23 24pure subroutine FortranMultAIJ(n,x,ii,jj,a,y) 25 use, intrinsic :: ISO_C_binding 26 implicit none (type, external) 27 PetscScalar, intent(in) :: x(0:*),a(0:*) 28 PetscScalar, intent(inout) :: y(*) 29 PetscInt, intent(in) :: n,ii(*),jj(0:*) 30 31 PetscInt :: i,jstart,jend 32 33#ifdef PETSC_USE_OPENMP_KERNELS 34 !omp parallel do private(jstart,jend) 35#endif 36 do i=1,n 37 jstart = ii(i) 38 jend = ii(i+1) 39 y(i) = sum(a(jstart:jend-1)*x(jj(jstart:jend-1))) 40 end do 41end subroutine FortranMultAIJ 42