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

  8:   DM :: dm
  9:   DMLabel :: label
 10:   Vec :: u
 11:   PetscViewer :: viewer
 12:   PetscSection :: section
 13:   PetscInt, parameter :: numFields = 3, numBC = 1
 14:   PetscInt :: dim, val
 15:   PetscInt, target, dimension(3) ::  numComp
 16:   PetscInt, pointer :: pNumComp(:)
 17:   PetscInt, target, dimension(12) ::  numDof
 18:   PetscInt, pointer :: pNumDof(:)
 19:   PetscInt, target, dimension(1) ::  bcField
 20:   PetscInt, pointer :: pBcField(:)
 21:   PetscMPIInt :: size
 22:   IS, target, dimension(1) ::   bcCompIS
 23:   IS, target, dimension(1) ::   bcPointIS
 24:   IS, pointer :: pBcCompIS(:)
 25:   IS, pointer :: pBcPointIS(:)
 26:   PetscErrorCode :: ierr

 28:   PetscCallA(PetscInitialize(ierr))
 29:   PetscCallMPIA(MPI_Comm_size(PETSC_COMM_WORLD, size, ierr))
 30: ! Create a mesh
 31:   PetscCallA(DMCreate(PETSC_COMM_WORLD, dm, ierr))
 32:   PetscCallA(DMSetType(dm, DMPLEX, ierr))
 33:   PetscCallA(DMSetFromOptions(dm, ierr))
 34:   PetscCallA(DMViewFromOptions(dm, PETSC_NULL_OBJECT, '-dm_view', ierr))
 35:   PetscCallA(DMGetDimension(dm, dim, ierr))
 36: ! Create a scalar field u, a vector field v, and a surface vector field w
 37:   numComp = [1_PETSC_INT_KIND, dim, dim - 1_PETSC_INT_KIND]
 38:   pNumComp => numComp
 39:   numDof(1:numFields*(dim + 1)) = 0
 40: ! Let u be defined on vertices
 41:   numDof(0*(dim + 1) + 1) = 1
 42: ! Let v be defined on cells
 43:   numDof(1*(dim + 1) + dim + 1) = dim
 44: ! Let v be defined on faces
 45:   numDof(2*(dim + 1) + dim) = dim - 1
 46:   pNumDof => numDof
 47: ! Test label retrieval
 48:   PetscCallA(DMGetLabel(dm, 'marker', label, ierr))
 49:   PetscCallA(DMLabelGetValue(label, 0_PETSC_INT_KIND, val, ierr))
 50:   PetscCheckA(size /= 1 .or. val == -1, PETSC_COMM_SELF, PETSC_ERR_PLIB, 'Error in library')
 51:   PetscCallA(DMLabelGetValue(label, 8_PETSC_INT_KIND, val, ierr))
 52:   PetscCheckA(size /= 1 .or. val == 1, PETSC_COMM_SELF, PETSC_ERR_PLIB, 'Error in library')
 53: ! Prescribe a Dirichlet condition on u on the boundary
 54: ! Label "marker" is made by the mesh creation routine
 55:   bcField(1) = 0
 56:   pBcField => bcField
 57:   PetscCallA(ISCreateStride(PETSC_COMM_WORLD, 1_PETSC_INT_KIND, 0_PETSC_INT_KIND, 1_PETSC_INT_KIND, bcCompIS(1), ierr))
 58:   pBcCompIS => bcCompIS
 59:   PetscCallA(DMGetStratumIS(dm, 'marker', 1_PETSC_INT_KIND, bcPointIS(1), ierr))
 60:   pBcPointIS => bcPointIS
 61: ! Create a PetscSection with this data layout
 62:   PetscCallA(DMSetNumFields(dm, numFields, ierr))
 63:   PetscCallA(DMPlexCreateSection(dm, PETSC_NULL_DMLABEL_ARRAY, pNumComp, pNumDof, numBC, pBcField, pBcCompIS, pBcPointIS, PETSC_NULL_IS, section, ierr))
 64:   PetscCallA(ISDestroy(bcCompIS(1), ierr))
 65:   PetscCallA(ISDestroy(bcPointIS(1), ierr))
 66: ! Name the Field variables
 67:   PetscCallA(PetscSectionSetFieldName(section, 0_PETSC_INT_KIND, 'u', ierr))
 68:   PetscCallA(PetscSectionSetFieldName(section, 1_PETSC_INT_KIND, 'v', ierr))
 69:   PetscCallA(PetscSectionSetFieldName(section, 2_PETSC_INT_KIND, 'w', ierr))
 70:   if (size == 1) then
 71:     PetscCallA(PetscSectionView(section, PETSC_VIEWER_STDOUT_WORLD, ierr))
 72:   end if
 73: ! Tell the DM to use this data layout
 74:   PetscCallA(DMSetLocalSection(dm, section, ierr))
 75: ! Create a Vec with this layout and view it
 76:   PetscCallA(DMGetGlobalVector(dm, u, ierr))
 77:   PetscCallA(PetscViewerCreate(PETSC_COMM_WORLD, viewer, ierr))
 78:   PetscCallA(PetscViewerSetType(viewer, PETSCVIEWERVTK, ierr))
 79:   PetscCallA(PetscViewerFileSetName(viewer, 'sol.vtu', ierr))
 80:   PetscCallA(VecView(u, viewer, ierr))
 81:   PetscCallA(PetscViewerDestroy(viewer, ierr))
 82:   PetscCallA(DMRestoreGlobalVector(dm, u, ierr))
 83: ! Cleanup
 84:   PetscCallA(PetscSectionDestroy(section, ierr))
 85:   PetscCallA(DMDestroy(dm, ierr))

 87:   PetscCallA(PetscFinalize(ierr))
 88: end program DMPlexTestField

 90: !/*TEST
 91: !
 92: !  test:
 93: !    suffix: 0
 94: !    requires: triangle
 95: !    args: -info :~sys,mat:
 96: !
 97: !  test:
 98: !    suffix: 0_2
 99: !    requires: triangle
100: !    nsize: 2
101: !    args: -info :~sys,mat,partitioner:
102: !
103: !  test:
104: !    suffix: 1
105: !    requires: ctetgen
106: !    args: -dm_plex_dim 3 -info :~sys,mat:
107: !
108: !TEST*/