1:       program DMPlexTestField
  2: #include "petsc/finclude/petscdmplex.h"
  3: #include "petsc/finclude/petscdmlabel.h"
  4:       use petscdmplex
  5:       use petscsys
  6:       implicit none

  8:       DM :: dm
  9:       DMLabel :: label
 10:       Vec :: u
 11:       PetscViewer :: viewer
 12:       PetscSection :: section
 13:       PetscInt :: dim,numFields,numBC
 14:       PetscInt :: i,val
 15:       DMLabel, pointer :: nolabel(:) => NULL()
 16:       PetscInt, target, dimension(3) ::  numComp
 17:       PetscInt, pointer :: pNumComp(:)
 18:       PetscInt, target, dimension(12) ::  numDof
 19:       PetscInt, pointer :: pNumDof(:)
 20:       PetscInt, target, dimension(1) ::  bcField
 21:       PetscInt, pointer :: pBcField(:)
 22:       PetscInt, parameter :: zero = 0, one = 1, two = 2, eight = 8
 23:       IS, target, dimension(1) ::   bcCompIS
 24:       IS, target, dimension(1) ::   bcPointIS
 25:       IS, pointer :: pBcCompIS(:)
 26:       IS, pointer :: pBcPointIS(:)
 27:       PetscBool :: interpolate,flg
 28:       PetscErrorCode :: ierr

 30:       call PetscInitialize(PETSC_NULL_CHARACTER, ierr)
 31:       if (ierr .ne. 0) then
 32:         print*,'Unable to initialize PETSc'
 33:         stop
 34:       endif
 35:       dim = 2
 36:       call PetscOptionsGetInt(PETSC_NULL_OPTIONS,PETSC_NULL_CHARACTER,'-dim', dim,flg, ierr);CHKERRA(ierr)
 37:       interpolate = PETSC_TRUE
 38: !     Create a mesh
 39:       call DMPlexCreateBoxMesh(PETSC_COMM_WORLD, dim, PETSC_TRUE, PETSC_NULL_INTEGER, PETSC_NULL_REAL, PETSC_NULL_REAL, PETSC_NULL_INTEGER, interpolate, dm, ierr);CHKERRA(ierr)
 40: !     Create a scalar field u, a vector field v, and a surface vector field w
 41:       numFields  = 3
 42:       numComp(1) = 1
 43:       numComp(2) = dim
 44:       numComp(3) = dim-1
 45:       pNumComp => numComp
 46:       do i = 1, numFields*(dim+1)
 47:          numDof(i) = 0
 48:       end do
 49: !     Let u be defined on vertices
 50:       numDof(0*(dim+1)+1)     = 1
 51: !     Let v be defined on cells
 52:       numDof(1*(dim+1)+dim+1) = dim
 53: !     Let v be defined on faces
 54:       numDof(2*(dim+1)+dim)   = dim-1
 55:       pNumDof => numDof
 56: !     Setup boundary conditions
 57:       numBC = 1
 58: !     Test label retrieval
 59:       call DMGetLabel(dm, 'marker', label, ierr);CHKERRA(ierr)
 60:       call DMLabelGetValue(label, zero, val, ierr);CHKERRA(ierr)
 61:       if (val .ne. -1) then
 62:         CHKERRA(1)
 63:       endif
 64:       call DMLabelGetValue(label, eight, val, ierr);CHKERRA(ierr)
 65:       if (val .ne. 1) then
 66:         CHKERRA(1)
 67:       endif
 68: !     Prescribe a Dirichlet condition on u on the boundary
 69: !       Label "marker" is made by the mesh creation routine
 70:       bcField(1) = 0
 71:       pBcField => bcField
 72:       call ISCreateStride(PETSC_COMM_WORLD, one, zero, one, bcCompIS(1), ierr);CHKERRA(ierr)
 73:       pBcCompIS => bcCompIS
 74:       call DMGetStratumIS(dm, 'marker', one, bcPointIS(1),ierr);CHKERRA(ierr)
 75:       pBcPointIS => bcPointIS
 76: !     Create a PetscSection with this data layout
 77:       call DMSetNumFields(dm, numFields,ierr);CHKERRA(ierr)
 78:       call DMPlexCreateSection(dm,nolabel,pNumComp,pNumDof,numBC,pBcField,pBcCompIS,pBcPointIS,PETSC_NULL_IS,section,ierr)
 79:       CHKERRA(ierr)
 80:       call ISDestroy(bcCompIS(1), ierr);CHKERRA(ierr)
 81:       call ISDestroy(bcPointIS(1), ierr);CHKERRA(ierr)
 82: !     Name the Field variables
 83:       call PetscSectionSetFieldName(section, zero, 'u', ierr);CHKERRA(ierr)
 84:       call PetscSectionSetFieldName(section, one,  'v', ierr);CHKERRA(ierr)
 85:       call PetscSectionSetFieldName(section, two,  'w', ierr);CHKERRA(ierr)
 86:       call PetscSectionView(section, PETSC_VIEWER_STDOUT_WORLD, ierr);CHKERRA(ierr)
 87: !     Tell the DM to use this data layout
 88:       call DMSetSection(dm, section, ierr);CHKERRA(ierr)
 89: !     Create a Vec with this layout and view it
 90:       call DMGetGlobalVector(dm, u, ierr);CHKERRA(ierr)
 91:       call PetscViewerCreate(PETSC_COMM_WORLD, viewer, ierr);CHKERRA(ierr)
 92:       call PetscViewerSetType(viewer, PETSCVIEWERVTK, ierr);CHKERRA(ierr)
 93:       call PetscViewerPushFormat(viewer, PETSC_VIEWER_ASCII_VTK, ierr);CHKERRA(ierr)
 94:       call PetscViewerFileSetName(viewer, 'sol.vtk', ierr);CHKERRA(ierr)
 95:       call VecView(u, viewer, ierr);CHKERRA(ierr)
 96:       call PetscViewerDestroy(viewer, ierr);CHKERRA(ierr)
 97:       call DMRestoreGlobalVector(dm, u, ierr);CHKERRA(ierr)
 98: !     Cleanup
 99:       call PetscSectionDestroy(section, ierr);CHKERRA(ierr)
100:       call DMDestroy(dm, ierr);CHKERRA(ierr)

102:       call PetscFinalize(ierr)
103:       end program DMPlexTestField

105: !/*TEST
106: !  build:
107: !    requires: define(PETSC_USING_F90FREEFORM)
108: !
109: !  test:
110: !    suffix: 0
111: !    requires: triangle
112: !
113: !  test:
114: !    suffix: 1
115: !    requires: ctetgen
116: !    args: -dim 3
117: !
118: !TEST*/