Actual source code: fmult.F
petsc-3.10.5 2019-03-28
Report Typos and Errors

      1: !
      2: !
      3: !    Fortran kernel for sparse matrix-vector product in the AIJ matrix format
      4: !
      5: #include <petsc/finclude/petscsys.h>
      6: !
      7:       subroutine FortranMultTransposeAddAIJ(n,x,ii,jj,a,y)
      8:       implicit none
      9:       PetscScalar x(0:*),a(0:*),y(0:*)
     10:       PetscScalar alpha
     11:       PetscInt    n,ii(*),jj(0:*)

     13:       PetscInt    i,j,jstart,jend

     15:       jend  = ii(1)
     16:       do 10,i=1,n
     17:         jstart = jend
     18:         jend   = ii(i+1)
     19:         alpha  = x(i-1)
     20:         do 20 j=jstart,jend-1
     21:           y(jj(j)) = y(jj(j)) + alpha*a(j)
     22:  20     continue
     23:  10   continue

     25:       return
     26:       end

     28:       subroutine FortranMultAIJ(n,x,ii,jj,a,y)
     29:       implicit none
     30:       PetscScalar x(0:*),a(0:*),y(*)
     31:       PetscInt    n,ii(*),jj(0:*)

     33:       PetscInt i,j,jstart,jend
     34:       PetscScalar  sum

     36:       jend  = ii(1)
     37:       do 10,i=1,n
     38:         jstart = jend
     39:         jend   = ii(i+1)
     40:         sum    = 0.d0
     41:         do 20 j=jstart,jend-1
     42:           sum = sum + a(j)*x(jj(j))
     43:  20     continue
     44:         y(i) = sum
     45:  10   continue

     47:       return
     48:       end