1: !
  2: ! "$Id: ex11f.F,v 1.11 2001/08/09 23:21:58 balay Exp $";
  3: !
  4: !
  5: ! Program usage:  mpirun ex1 [-help] [all PETSc options]
  6: !
  7: !
  8: !/*T
  9: !   Concepts: vectors^norms of sub-vectors;
 10: !   Processors: n
 11: !T*/

 13:       program main
 14:       implicit none

 16: !
 17: !  The following include statements are required for Fortran programs
 18: !  that use PETSc vectors:
 19: !     petsc.h       - base PETSc routines
 20: !     petscvec.h    - vectors
 21: !  Additional include statements may be needed if using additional
 22: !  PETSc routines in a Fortran program, e.g.,
 23: !     petscviewer.h - viewers
 24: !     petscis.h     - index sets
 25: !
 26:  #include include/finclude/petsc.h
 27:  #include include/finclude/petscvec.h
 28: !

 30:       Vec               x
 31:       PetscReal         norm
 32:       integer           n,ierr,flg,rank
 33:       PetscScalar       one

 35:       call PetscInitialize(PETSC_NULL_CHARACTER,ierr)
 36:       call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr)

 38:       n   = 20
 39:       one = 1.d0
 40:       call PetscOptionsGetInt(PETSC_NULL_CHARACTER,'-n',n,flg,ierr)

 42: !
 43: !     Create a vector, specifying only its global dimension.
 44: !     When using VecCreate(), VecSetSizes() and VecSetFromOptions(),
 45: !     the vector format (currently parallel,
 46: !     shared, or sequential) is determined at runtime.  Also, the parallel
 47: !     partitioning of the vector is determined by PETSc at runtime.
 48: !
 49: !     Routines for creating particular vector types directly are:
 50: !        VecCreateSeq() - uniprocessor vector
 51: !        VecCreateMPI() - distributed vector, where the user can
 52: !                         determine the parallel partitioning
 53: !        VecCreateShared() - parallel vector that uses shared memory
 54: !                            (available only on the SGI); otherwise,
 55: !                            is the same as VecCreateMPI()
 56: !
 57: !     With VecCreate(), VecSetSizes() and VecSetFromOptions() the option
 58: !     -vec_type mpi or -vec_type shared causes the
 59: !     particular type of vector to be formed.

 61:       call VecCreate(PETSC_COMM_WORLD,x,ierr)
 62:       call VecSetSizes(x,PETSC_DECIDE,n,ierr)
 63:       call VecSetFromOptions(x,ierr)

 65: !
 66: !     Set the vectors to entries to a constant value.
 67: !
 68:       call VecSet(one,x,ierr)

 70:       call VecNorm(x,NORM_2,norm,ierr)
 71:       if (rank .eq. 0) then
 72:          write (6,100) norm
 73:  100     format ('Norm of entire vector ',1pe8.2)
 74:       endif

 76:       call VecSetBlockSize(x,2,ierr)
 77:       call VecStrideNorm(x,0,NORM_2,norm,ierr)
 78:       if (rank .eq. 0) then
 79:          write (6,200) norm
 80:  200     format ('Norm of subvector ',1pe8.2)
 81:       endif


 84:       call VecStrideNorm(x,1,NORM_2,norm,ierr)
 85:       if (rank .eq. 0) then
 86:          write (6,300) norm
 87:  300     format ('Norm of subvector ',1pe8.2)
 88:       endif

 90:       call VecStrideNorm(x,1,NORM_1,norm,ierr)
 91:       if (rank .eq. 0) then
 92:          write (6,400) norm
 93:  400     format ('Norm of subvector ',1pe8.2)
 94:       endif

 96:       call VecStrideNorm(x,1,NORM_INFINITY,norm,ierr)
 97:       if (rank .eq. 0) then
 98:          write (6,500) norm
 99:  500     format ('Norm of subvector ',1pe8.2)
100:       endif

102: !
103: !     Free work space.  All PETSc objects should be destroyed when they
104: !     are no longer needed.

106:       call VecDestroy(x,ierr)
107:       call PetscFinalize(ierr)
108:       end
109: