1: program main

  3: #include <petsc/finclude/petscvec.h>
  4: #include <petsc/finclude/petscmat.h>

  6:   use petscvec
  7:   use petscmat

  9:   implicit none

 11:   Mat             :: A
 12:   MatPartitioning :: part
 13:   IS              :: is
 14:   PetscInt        :: r, myStart, myEnd
 15:   PetscInt        :: N = 10
 16:   PetscErrorCode  :: ierr
 17:   PetscScalar, pointer, dimension(:) :: vals
 18:   PetscInt, pointer, dimension(:) :: cols
 19:   PetscBool :: flg
 20:   PetscInt, parameter :: one = 1, two = 2, three = 3

 22:   PetscCallA(PetscInitialize(ierr))

 24:   PetscCallA(PetscOptionsGetInt(PETSC_NULL_OPTIONS, PETSC_NULL_CHARACTER, '-N', N, flg, ierr))
 25:   PetscCallA(MatCreate(PETSC_COMM_WORLD, A, ierr))
 26:   PetscCallA(MatSetSizes(A, PETSC_DECIDE, PETSC_DECIDE, N, N, ierr))
 27:   PetscCallA(MatSetFromOptions(A, ierr))
 28:   PetscCallA(MatSeqAIJSetPreallocation(A, three, PETSC_NULL_INTEGER_ARRAY, ierr))
 29:   PetscCallA(MatMPIAIJSetPreallocation(A, three, PETSC_NULL_INTEGER_ARRAY, two, PETSC_NULL_INTEGER_ARRAY, ierr))

 31:   !/* Create a linear mesh */
 32:   PetscCallA(MatGetOwnershipRange(A, myStart, myEnd, ierr))

 34:   do r = myStart, myEnd - 1
 35:     if (r == 0) then
 36:       allocate (vals(2))
 37:       vals = 1.0
 38:       allocate (cols(2), source=[r, r + 1])
 39:       PetscCallA(MatSetValues(A, one, [r], two, cols, vals, INSERT_VALUES, ierr))
 40:       deallocate (cols)
 41:       deallocate (vals)
 42:     else if (r == N - 1) then
 43:       allocate (vals(2))
 44:       vals = 1.0
 45:       allocate (cols(2), source=[r - 1, r])
 46:       PetscCallA(MatSetValues(A, one, [r], two, cols, vals, INSERT_VALUES, ierr))
 47:       deallocate (cols)
 48:       deallocate (vals)
 49:     else
 50:       allocate (vals(3))
 51:       vals = 1.0
 52:       allocate (cols(3), source=[r - 1, r, r + 1])
 53:       PetscCallA(MatSetValues(A, one, [r], three, cols, vals, INSERT_VALUES, ierr))
 54:       deallocate (cols)
 55:       deallocate (vals)
 56:     end if
 57:   end do
 58:   PetscCallA(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY, ierr))
 59:   PetscCallA(MatAssemblyend(A, MAT_FINAL_ASSEMBLY, ierr))
 60:   PetscCallA(MatPartitioningCreate(PETSC_COMM_WORLD, part, ierr))
 61:   PetscCallA(MatPartitioningSetAdjacency(part, A, ierr))
 62:   PetscCallA(MatPartitioningSetFromOptions(part, ierr))
 63:   PetscCallA(MatPartitioningApply(part, is, ierr))
 64:   PetscCallA(ISView(is, PETSC_VIEWER_STDOUT_WORLD, ierr))
 65:   PetscCallA(ISDestroy(is, ierr))
 66:   PetscCallA(MatPartitioningDestroy(part, ierr))
 67:   PetscCallA(MatDestroy(A, ierr))
 68:   PetscCallA(PetscFinalize(ierr))

 70: end program

 72: !/*TEST
 73: !
 74: !   test:
 75: !      nsize: 3
 76: !      requires: parmetis
 77: !      args: -mat_partitioning_type parmetis
 78: !      output_file: output/ex15_1.out
 79: !
 80: !   test:
 81: !      suffix: 2
 82: !      nsize: 3
 83: !      requires: ptscotch
 84: !      args: -mat_partitioning_type ptscotch
 85: !      output_file: output/ex15_2.out
 86: !
 87: !   test:
 88: !      suffix: 3
 89: !      nsize: 4
 90: !      requires: party
 91: !      args: -mat_partitioning_type party
 92: !      output_file: output/ex15_3.out
 93: !
 94: !   test:
 95: !      suffix: 4
 96: !      nsize: 3
 97: !      requires: chaco
 98: !      args: -mat_partitioning_type chaco
 99: !      output_file: output/ex15_4.out
100: !
101: !   test:
102: !      suffix: 5
103: !      nsize: 3
104: !      requires: parmetis
105: !      args: -mat_partitioning_type hierarch -mat_partitioning_hierarchical_nfineparts 3 -mat_partitioning_nparts 10 -N 100
106: !      output_file: output/ex15_5.out
107: !
108: !TEST*/