1: !
  2: #include <petsc/finclude/petscvec.h>
  3: program main
  4:   use petscvec
  5:   implicit none

  7:   Vec x
  8:   PetscReal norm
  9:   PetscBool flg
 10:   PetscMPIInt rank
 11:   PetscInt, parameter :: bs = 2 ! block size
 12:   PetscInt n, comp
 13:   PetscErrorCode ierr
 14:   PetscScalar, parameter :: one = 1.0

 16:   PetscCallA(PetscInitialize(ierr))
 17:   PetscCallMPIA(MPI_Comm_rank(PETSC_COMM_WORLD, rank, ierr))

 19:   n = 20
 20:   PetscCallA(PetscOptionsGetInt(PETSC_NULL_OPTIONS, PETSC_NULL_CHARACTER, '-n', n, flg, ierr))

 22: !
 23: !     Create a vector, specifying only its global dimension.
 24: !     When using VecCreate(), VecSetSizes() and VecSetFromOptions(),
 25: !     the vector format (currently parallel,
 26: !     shared, or sequential) is determined at runtime.  Also, the parallel
 27: !     partitioning of the vector is determined by PETSc at runtime.

 29:   PetscCallA(VecCreate(PETSC_COMM_WORLD, x, ierr))
 30:   PetscCallA(VecSetSizes(x, PETSC_DECIDE, n, ierr))
 31:   PetscCallA(VecSetBlockSize(x, bs, ierr))
 32:   PetscCallA(VecSetFromOptions(x, ierr))

 34: !
 35: !     Set the vectors to entries to a constant value.
 36: !
 37:   PetscCallA(VecSet(x, one, ierr))

 39:   PetscCallA(VecNorm(x, NORM_2, norm, ierr))
 40:   if (rank == 0) then
 41:     write (6, 100) norm
 42: 100 format('L_2 Norm of entire vector ', 1pe9.2)
 43:   end if

 45:   comp = 0
 46:   PetscCallA(VecStrideNorm(x, comp, NORM_2, norm, ierr))
 47:   if (rank == 0) then
 48:     write (6, 200) norm
 49: 200 format('L_2 Norm of subvector 0', 1pe9.2)
 50:   end if

 52:   comp = 1
 53:   PetscCallA(VecStrideNorm(x, comp, NORM_2, norm, ierr))
 54:   if (rank == 0) then
 55:     write (6, 300) norm
 56: 300 format('L_2 Norm of subvector 1', 1pe9.2)
 57:   end if

 59:   PetscCallA(VecStrideNorm(x, comp, NORM_1, norm, ierr))
 60:   if (rank == 0) then
 61:     write (6, 400) norm
 62: 400 format('L_1 Norm of subvector 0', 1pe9.2)
 63:   end if

 65:   PetscCallA(VecStrideNorm(x, comp, NORM_INFINITY, norm, ierr))
 66:   if (rank == 0) then
 67:     write (6, 500) norm
 68: 500 format('L_1 Norm of subvector 1', 1pe9.2)
 69:   end if

 71: !
 72: !     Free work space.  All PETSc objects should be destroyed when they
 73: !     are no longer needed.

 75:   PetscCallA(VecDestroy(x, ierr))
 76:   PetscCallA(PetscFinalize(ierr))
 77: end

 79: !/*TEST
 80: !
 81: !     test:
 82: !       nsize: 2
 83: !
 84: !TEST*/