xref: /petsc/src/mat/impls/aij/seq/ftn-kernels/fmultadd.F90 (revision 0113e7197f2fe148981cb35224c0458dc22f510d)
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!
7c96caaccSSatish Balaysubroutine FortranMultAddAIJ(n,x,ii,jj,a,y,z)
8c96caaccSSatish Balay  implicit none
9c96caaccSSatish Balay  PetscScalar      x(0:*),a(0:*),y(*),z(*)
10c96caaccSSatish Balay  PetscInt          n,ii(*),jj(0:*)
11c96caaccSSatish Balay
12c96caaccSSatish Balay  PetscInt i,j,jstart,jend
13c96caaccSSatish Balay  PetscScalar  sum
14c96caaccSSatish Balay
15c96caaccSSatish Balay  jend  = ii(1)
16*0113e719SMartin Diehl  do i=1,n
17c96caaccSSatish Balay    jstart = jend
18c96caaccSSatish Balay    jend   = ii(i+1)
19c96caaccSSatish Balay    sum    = y(i)
20*0113e719SMartin Diehl    do j=jstart,jend-1
21c96caaccSSatish Balay      sum = sum + a(j)*x(jj(j))
22*0113e719SMartin Diehl    end do
23c96caaccSSatish Balay    z(i) = sum
24*0113e719SMartin Diehl  end do
25c96caaccSSatish Balay
26*0113e719SMartin Diehlend subroutine FortranMultAddAIJ
27