1c96caaccSSatish Balay! 2c96caaccSSatish Balay! 3c96caaccSSatish Balay! Fortran kernel for sparse matrix-vector product in the AIJ format 4c96caaccSSatish Balay! 5c96caaccSSatish Balay#include <petsc/finclude/petscsys.h> 6c96caaccSSatish Balay! 70ccf82acSMartin Diehlpure subroutine FortranMultAddAIJ(n,x,ii,jj,a,y,z) 8*fe66ebccSMartin Diehl use, intrinsic :: ISO_C_binding 90ccf82acSMartin Diehl implicit none (type, external) 100ccf82acSMartin Diehl PetscScalar, intent(in) :: x(0:*),a(0:*),y(*) 110ccf82acSMartin Diehl PetscScalar, intent(inout) :: z(*) 120ccf82acSMartin Diehl PetscInt, intent(in) :: n,ii(*),jj(0:*) 13c96caaccSSatish Balay 14ff45ff59SMartin Diehl PetscInt :: i,jstart,jend 15c96caaccSSatish Balay 16c96caaccSSatish Balay jend = ii(1) 170113e719SMartin Diehl do i=1,n 18c96caaccSSatish Balay jstart = jend 19c96caaccSSatish Balay jend = ii(i+1) 20d66e387eSMartin Diehl z(i) = y(i) + sum(a(jstart:jend-1)*x(jj(jstart:jend-1))) 210113e719SMartin Diehl end do 220113e719SMartin Diehlend subroutine FortranMultAddAIJ 23