1:    !Concepts: vectors^norms of sub-vectors
  2:    !Processors: n

  4:   program main
  5: #include <petsc/finclude/petscvec.h>
  6:   use petscvec
  7:   implicit none

  9:   Vec        ::   x
 10:   PetscReal  :: norm
 11:   PetscMPIInt :: rank
 12:   PetscInt,parameter :: n = 20
 13:   PetscErrorCode :: ierr
 14:   PetscScalar,parameter :: sone = 1.0
 15:   PetscBool :: flg
 16:   character(len=PETSC_MAX_PATH_LEN) :: outputString
 17:   PetscInt,parameter :: zero = 0, one = 1, two = 2

 19:   call PetscInitialize(PETSC_NULL_CHARACTER,ierr)
 20:   if (ierr /= 0) then
 21:    print*,'PetscInitialize failed'
 22:    stop
 23:   endif

 25:   call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr)

 27:   call PetscOptionsGetInt(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,"-n",n,flg,ierr);CHKERRA(ierr)


 30:      !Create a vector, specifying only its global dimension.
 31:      !When using VecCreate(), VecSetSizes() and VecSetFromOptions(),
 32:      !the vector format (currently parallel,
 33:      !shared, or sequential) is determined at runtime.  Also, the parallel
 34:      !partitioning of the vector is determined by PETSc at runtime.

 36:      !Routines for creating particular vector types directly are:
 37:      !VecCreateSeq() - uniprocessor vector
 38:      !VecCreateMPI() - distributed vector, where the user can
 39:                          !determine the parallel partitioning
 40:         !VecCreateShared() - parallel vector that uses shared memory
 41:                             !(available only on the SGI) otherwise,
 42:                             !is the same as VecCreateMPI()

 44:      !With VecCreate(), VecSetSizes() and VecSetFromOptions() the option
 45:      !-vec_type mpi or -vec_type shared causes the
 46:      !particular type of vector to be formed.

 48:   call VecCreate(PETSC_COMM_WORLD,x,ierr);CHKERRA(ierr)

 50:   call VecSetSizes(x,PETSC_DECIDE,n,ierr);CHKERRA(ierr)
 51:   !
 52:   call VecSetBlockSize(x,two,ierr);CHKERRA(ierr)
 53:   call VecSetFromOptions(x,ierr);CHKERRA(ierr)


 56:      !Set the vectors to entries to a constant value.

 58:   call VecSet(x,sone,ierr);CHKERRA(ierr)

 60:   call VecNorm(x,NORM_2,norm,ierr);CHKERRA(ierr)
 61:   write(outputString,*) norm
 62:   call PetscPrintf(PETSC_COMM_WORLD,"L_2 Norm of entire vector: "//trim(outputString)//"\n",ierr);CHKERRA(ierr)

 64:   call VecNorm(x,NORM_1,norm,ierr);CHKERRA(ierr)
 65:   write(outputString,*) norm
 66:   call PetscPrintf(PETSC_COMM_WORLD,"L_1 Norm of entire vector: "//trim(outputString)//"\n",ierr);CHKERRA(ierr)

 68:   call VecNorm(x,NORM_INFINITY,norm,ierr);CHKERRA(ierr)
 69:   write(outputString,*) norm
 70:   call PetscPrintf(PETSC_COMM_WORLD,"L_inf Norm of entire vector: "//trim(outputString)//"\n",ierr);CHKERRA(ierr)

 72:   call VecStrideNorm(x,zero,NORM_2,norm,ierr);CHKERRA(ierr)
 73:   write(outputString,*) norm
 74:   call PetscPrintf(PETSC_COMM_WORLD,"L_2 Norm of sub-vector 0: "//trim(outputString)//"\n",ierr);CHKERRA(ierr)

 76:   call VecStrideNorm(x,zero,NORM_1,norm,ierr);CHKERRA(ierr)
 77:   write(outputString,*) norm
 78:   call PetscPrintf(PETSC_COMM_WORLD,"L_1 Norm of sub-vector 0: "//trim(outputString)//"\n",ierr);CHKERRA(ierr)

 80:   call VecStrideNorm(x,zero,NORM_INFINITY,norm,ierr);CHKERRA(ierr)
 81:   write(outputString,*) norm
 82:   call PetscPrintf(PETSC_COMM_WORLD,"L_inf Norm of sub-vector 0: "//trim(outputString)//"\n",ierr);CHKERRA(ierr)

 84:   call VecStrideNorm(x,one,NORM_2,norm,ierr);CHKERRA(ierr)
 85:   write(outputString,*) norm
 86:   call PetscPrintf(PETSC_COMM_WORLD,"L_2 Norm of sub-vector 1: "//trim(outputString)//"\n",ierr);CHKERRA(ierr)

 88:   call VecStrideNorm(x,one,NORM_1,norm,ierr);CHKERRA(ierr)
 89:   write(outputString,*) norm
 90:   call PetscPrintf(PETSC_COMM_WORLD,"L_1 Norm of sub-vector 1: "//trim(outputString)//"\n",ierr);CHKERRA(ierr)

 92:   call VecStrideNorm(x,one,NORM_INFINITY,norm,ierr);CHKERRA(ierr)
 93:   write(outputString,*) norm
 94:   call PetscPrintf(PETSC_COMM_WORLD,"L_inf Norm of sub-vector 1: "//trim(outputString)//"\n",ierr);CHKERRA(ierr)


 97:      !Free work space.  All PETSc objects should be destroyed when they
 98:      !are no longer needed.
 99:   call VecDestroy(x,ierr);CHKERRA(ierr)
100:   call PetscFinalize(ierr);CHKERRA(ierr)

102: end program


105: !/*TEST
106: !
107: !     test:
108: !       nsize: 2
109: !
110: !TEST*/