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! 7*0ccf82acSMartin Diehlpure subroutine FortranMultAddAIJ(n,x,ii,jj,a,y,z) 8*0ccf82acSMartin Diehl implicit none (type, external) 9*0ccf82acSMartin Diehl PetscScalar, intent(in) :: x(0:*),a(0:*),y(*) 10*0ccf82acSMartin Diehl PetscScalar, intent(inout) :: z(*) 11*0ccf82acSMartin Diehl PetscInt, intent(in) :: n,ii(*),jj(0:*) 12c96caaccSSatish Balay 13c96caaccSSatish Balay PetscInt i,j,jstart,jend 14c96caaccSSatish Balay PetscScalar sum 15c96caaccSSatish Balay 16c96caaccSSatish Balay jend = ii(1) 170113e719SMartin Diehl do i=1,n 18c96caaccSSatish Balay jstart = jend 19c96caaccSSatish Balay jend = ii(i+1) 20c96caaccSSatish Balay sum = y(i) 210113e719SMartin Diehl do j=jstart,jend-1 22c96caaccSSatish Balay sum = sum + a(j)*x(jj(j)) 230113e719SMartin Diehl end do 24c96caaccSSatish Balay z(i) = sum 250113e719SMartin Diehl end do 260113e719SMartin Diehlend subroutine FortranMultAddAIJ 27