!
!
#include <petsc/finclude/petscmat.h>
program main
  use petscmat
  implicit none

  PetscErrorCode ierr
  PetscInt i, one, twelve, j
  Mat m
  PetscScalar value

  PetscCallA(PetscInitialize(ierr))
  twelve = 12
  PetscCallA(MatCreate(PETSC_COMM_WORLD, m, ierr))
  PetscCallA(MatSetSizes(m, PETSC_DECIDE, PETSC_DECIDE, twelve, twelve, ierr))
  PetscCallA(MatSetFromOptions(m, ierr))
  PetscCallA(MatMPIAIJSetPreallocation(m, PETSC_DEFAULT_INTEGER, PETSC_NULL_INTEGER_ARRAY, PETSC_DEFAULT_INTEGER, PETSC_NULL_INTEGER_ARRAY, ierr))

  value = 3.0
  i = 4
  one = 1
  PetscCallA(MatSetValuesMPIAIJ(m, one, [i], one, [i], [value], ADD_VALUES, ierr))
  i = 5
  j = 7
  PetscCallA(MatSetValuesMPIAIJ(m, one, [i], one, [j], [value], ADD_VALUES, ierr))
  i = 10
  j = 9
  PetscCallA(MatSetValuesMPIAIJ(m, one, [i], one, [j], [value], ADD_VALUES, ierr))
  PetscCallA(MatAssemblyBegin(m, MAT_FINAL_ASSEMBLY, ierr))
  PetscCallA(MatAssemblyEnd(m, MAT_FINAL_ASSEMBLY, ierr))

  PetscCallA(MatDestroy(m, ierr))
  PetscCallA(PetscFinalize(ierr))
end

!/*TEST
!
!   test:
!      nsize: 2
!      output_file: output/empty.out
!
!TEST*/