1! 2! 3! Fortran kernel for sparse matrix-vector product in the AIJ format 4! 5#include <petsc/finclude/petscsys.h> 6! 7 subroutine FortranMultAddAIJ(n,x,ii,jj,a,y,z) 8 implicit none 9 PetscScalar x(0:*),a(0:*),y(*),z(*) 10 PetscInt n,ii(*),jj(0:*) 11 12 PetscInt i,j,jstart,jend 13 PetscScalar sum 14 15 jend = ii(1) 16 do 10,i=1,n 17 jstart = jend 18 jend = ii(i+1) 19 sum = y(i) 20 do 20 j=jstart,jend-1 21 sum = sum + a(j)*x(jj(j)) 22 20 continue 23 z(i) = sum 24 10 continue 25 26 end 27