xref: /petsc/src/mat/impls/aij/seq/ftn-kernels/fmult.F90 (revision edb0e59d3c097acd4a4005a4e51d4daa5c739255)
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3c96caaccSSatish Balay!    Fortran kernel for sparse matrix-vector product in the AIJ matrix format
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5c96caaccSSatish Balay#include <petsc/finclude/petscsys.h>
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70ccf82acSMartin Diehlpure subroutine FortranMultTransposeAddAIJ(n, x, ii, jj, a, y)
8*fe66ebccSMartin Diehl  use, intrinsic :: ISO_C_binding
90ccf82acSMartin Diehl  implicit none(type, external)
100ccf82acSMartin Diehl  PetscScalar, intent(in) :: x(0:*), a(0:*)
110ccf82acSMartin Diehl  PetscScalar, intent(inout) :: y(0:*)
120ccf82acSMartin Diehl  PetscInt, intent(in) :: n, ii(*), jj(0:*)
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14d66e387eSMartin Diehl  PetscInt :: i, jstart, jend
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16c96caaccSSatish Balay  jend = ii(1)
170113e719SMartin Diehl  do i = 1, n
18c96caaccSSatish Balay    jstart = jend
19c96caaccSSatish Balay    jend = ii(i + 1)
20d66e387eSMartin Diehl    y(jj(jstart:jend - 1)) = y(jj(jstart:jend - 1)) + x(i - 1)*a(jstart:jend - 1)
210113e719SMartin Diehl  end do
220113e719SMartin Diehlend subroutine FortranMultTransposeAddAIJ
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240ccf82acSMartin Diehlpure subroutine FortranMultAIJ(n, x, ii, jj, a, y)
25*fe66ebccSMartin Diehl  use, intrinsic :: ISO_C_binding
260ccf82acSMartin Diehl  implicit none(type, external)
270ccf82acSMartin Diehl  PetscScalar, intent(in) :: x(0:*), a(0:*)
280ccf82acSMartin Diehl  PetscScalar, intent(inout) :: y(*)
290ccf82acSMartin Diehl  PetscInt, intent(in) :: n, ii(*), jj(0:*)
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31d66e387eSMartin Diehl  PetscInt :: i, jstart, jend
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335161815cSJunchao Zhang#ifdef PETSC_USE_OPENMP_KERNELS
34ff45ff59SMartin Diehl  !omp parallel do private(jstart,jend)
355161815cSJunchao Zhang#endif
360113e719SMartin Diehl  do i = 1, n
375161815cSJunchao Zhang    jstart = ii(i)
38c96caaccSSatish Balay    jend = ii(i + 1)
39d66e387eSMartin Diehl    y(i) = sum(a(jstart:jend - 1)*x(jj(jstart:jend - 1)))
400113e719SMartin Diehl  end do
410113e719SMartin Diehlend subroutine FortranMultAIJ
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