vtk_file.f90

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module vtk_file
  use num_types, only : dp, dp
  use generic_file, only : generic_file_t
  use utils, only : neko_error, filename_suffix_pos
  use mesh, only : mesh_t
  use field, only : field_t
  use dofmap, only : dofmap_t
  use mesh_field, only : mesh_fld_t
  use tet_mesh, only : tet_mesh_t
  use htable, only : htable_i4_t
  use tri_mesh, only : tri_mesh_t
  use logger, only : neko_log
  use comm, only : pe_size, pe_rank
  implicit none
  private
 
  type, public, extends(generic_file_t) :: vtk_file_t
   contains
     procedure :: read => vtk_file_read
     procedure :: write => vtk_file_write
     procedure :: get_next_output_fname => vtk_file_get_next_output_fname
  end type vtk_file_t
 
contains
 
  function vtk_file_get_next_output_fname(this) result(fname)
    class(vtk_file_t), intent(in) :: this
    character(len=1024) :: fname
    character(len=10) :: id_str
    integer :: suffix_pos
 
    fname = this%get_base_fname()
    if (pe_size .gt. 1) then
       write(id_str, '(i10.10)') pe_rank
       suffix_pos = filename_suffix_pos(fname)
       fname = trim(fname(1:suffix_pos-1)) // id_str // '.vtk'
    end if
 
  end function vtk_file_get_next_output_fname
 
  subroutine vtk_file_write(this, data, t)
    class(vtk_file_t), intent(inout) :: this
    class(*), target, intent(in) :: data
    real(kind=dp), intent(in), optional :: t
    type(mesh_t), pointer :: msh => null()
    type(field_t), pointer :: fld => null()
    type(mesh_fld_t), pointer :: mfld => null()
    type(dofmap_t), pointer :: dm => null()
    type(tet_mesh_t), pointer :: tet_msh => null()
    type(tri_mesh_t), pointer :: tri_msh => null()
    integer :: file_unit
    character(len=1024) :: fname
 
    select type (data)
    type is (mesh_t)
       msh => data
    type is (field_t)
       msh => data%msh
       fld => data
    type is (mesh_fld_t)
       msh => data%msh
       mfld => data
    type is (dofmap_t)
       dm => data
    type is (tet_mesh_t)
       tet_msh => data
    type is (tri_mesh_t)
       tri_msh => data
    class default
       call neko_log%error('Invalid data')
    end select
 
    fname = this%get_next_output_fname()
    open(newunit = file_unit, file = trim(fname))
 
    ! Write legacy header
    write(file_unit, fmt = '(A)') '# vtk DataFile Version 2.0'
    write(file_unit, fmt = '(A)') 'Neko'
    write(file_unit, fmt = '(A)') 'ASCII'
 
    if (associated(msh)) then
       write(file_unit, fmt = '(A)') 'DATASET UNSTRUCTURED_GRID'
 
       call vtk_file_write_mesh(9, msh)
 
       if (associated(mfld)) then
          call vtk_file_write_cell_data(9, mfld)
       else if (associated(fld)) then
          call vtk_file_write_point_data(9, fld)
       end if
    else if (associated(dm)) then
       write(file_unit, fmt = '(A)') 'DATASET POLYDATA'
 
       call vtk_file_write_dofmap_coordinates(9, dm)
 
       call vtk_file_write_dofmap_data(9, dm)
    else if (associated(tet_msh)) then
       write(file_unit, fmt = '(A)') 'DATASET UNSTRUCTURED_GRID'
       call vtk_file_write_tet_mesh(9, tet_msh)
    else if (associated(tri_msh)) then
       write(file_unit, fmt = '(A)') 'DATASET UNSTRUCTURED_GRID'
       call vtk_file_write_tri_mesh(9, tri_msh)
    else
       call neko_error('Invalid data')
    end if
 
    close(file_unit)
  end subroutine vtk_file_write
 
  subroutine vtk_file_read(this, data)
    class(vtk_file_t) :: this
    class(*), target, intent(inout) :: data
 
    call neko_error('VTK file read not implemented')
  end subroutine vtk_file_read
 
  subroutine vtk_file_write_mesh(unit, msh)
    integer :: unit
    type(mesh_t), intent(inout) :: msh
    integer :: i, j, vtk_type
    integer, dimension(8), parameter :: vcyc_to_sym = [1, 2, 4, 3, &
         5, 6, 8, 7]
    ! pt_lid only exists on a mesh whose connectivity was generated
    if (.not. allocated(msh%pt_lid)) then
       call neko_error('VTK output requires a mesh with generated connectivity')
    end if
 
    ! Dump coordinates
    write(unit, fmt = '(A,I8,A)') 'POINTS', msh%mpts, ' double'
    do i = 1, msh%mpts
       write(unit, fmt = '(F15.8,F15.8,F15.8)') real(msh%points(i)%x, dp)
    end do
 
    ! Dump cells
    write(unit, fmt = '(A,I8,I8)') 'CELLS', msh%nelv, msh%nelv*(msh%npts+1)
    j = 0
    do i = 1, msh%nelv
       write(unit, fmt = '(I8,8I8)') msh%npts, &
            (msh%pt_lid(vcyc_to_sym(j), i) - 1, j = 1, msh%npts)
    end do
 
    ! Dump cell type for each element
    write(unit, fmt = '(A,I8)') 'CELL_TYPES', msh%nelv
    vtk_type = 9
    if (msh%gdim .eq. 3) vtk_type = 12
    do i = 1, msh%nelv
       write(unit, fmt = '(I2)') vtk_type
    end do
 
  end subroutine vtk_file_write_mesh
 
  subroutine vtk_file_write_cell_data(unit, mfld)
    integer :: unit
    type(mesh_fld_t), intent(in) :: mfld
    integer :: i
 
    write(unit, fmt = '(A,I8)') 'CELL_DATA', mfld%msh%nelv
    write(unit, fmt = '(A,A,A,I8)') 'SCALARS ', trim(mfld%name), ' int', 1
    write(unit, fmt = '(A)') 'LOOKUP_TABLE default'
 
    do i = 1, mfld%msh%nelv
       write(unit, fmt = '(I8)') mfld%data(i)
    end do
 
  end subroutine vtk_file_write_cell_data
 
  subroutine vtk_file_write_point_data(unit, fld)
    integer :: unit
    type(field_t), intent(inout) :: fld
    real(kind=dp), allocatable :: point_data(:)
    integer :: i, j, lx, ly, lz, id(8)
 
    if ( (fld%Xh%lx - 1 .gt. 1) .or. &
         (fld%Xh%ly - 1 .gt. 1) .or. &
         (fld%Xh%lz - 1 .gt. 1)) then
       call neko_log%warning("Interpolate high-order data onto a " // &
            "low-order mesh")
    end if
 
    write(unit, fmt = '(A,I8)') 'POINT_DATA', fld%msh%mpts
    write(unit, fmt = '(A,A,A,I8)') 'SCALARS ', trim(fld%name), ' double', 1
    write(unit, fmt = '(A)') 'LOOKUP_TABLE default'
 
    lx = fld%Xh%lx
    ly = fld%Xh%ly
    lz = fld%Xh%lz
    if (.not. allocated(fld%msh%pt_lid)) then
       call neko_error('VTK output requires a mesh with generated connectivity')
    end if
 
    allocate(point_data(fld%msh%mpts))
 
    do i = 1, fld%msh%nelv
       do j = 1, fld%msh%npts
          id(j) = fld%msh%pt_lid(j, i)
       end do
 
       point_data(id(1)) = real(fld%x(1, 1, 1, i), dp)
       point_data(id(2)) = real(fld%x(lx, 1, 1, i), dp)
       point_data(id(3)) = real(fld%x(1, ly, 1, i), dp)
       point_data(id(4)) = real(fld%x(lx, ly, 1, i), dp)
 
       if (fld%msh%gdim .eq. 3) then
          point_data(id(5)) = real(fld%x(1, 1, lz, i), dp)
          point_data(id(6)) = real(fld%x(lx, 1, lz, i), dp)
          point_data(id(7)) = real(fld%x(1, ly, lz, i), dp)
          point_data(id(8)) = real(fld%x(lx, ly, lz, i), dp)
       end if
 
    end do
 
    write(unit, *) point_data
 
    deallocate(point_data)
 
  end subroutine vtk_file_write_point_data
 
  subroutine vtk_file_write_dofmap_coordinates(unit, dm)
    integer :: unit
    type(dofmap_t), intent(inout) :: dm
    integer :: i, j, k, l
 
    write(unit, fmt = '(A,I8,A)') 'POINTS', size(dm%x), ' double'
 
    do i = 1, dm%msh%nelv
       do l = 1, dm%Xh%lz
          do k = 1, dm%Xh%ly
             do j = 1, dm%Xh%lx
                write(unit, fmt = '(F15.8,F15.8,F15.8)') &
                     real(dm%x(j,k,l,i), dp), &
                     real(dm%y(j,k,l,i), dp), &
                     real(dm%z(j,k,l,i), dp)
             end do
          end do
       end do
    end do
 
    write(unit, fmt = '(A,I8,I8)') 'VERTICES', size(dm%x), 2*size(dm%x)
    do i = 1, size(dm%x)
       write(unit, fmt = '(I8,I8)') 1, i-1
    end do
 
 
  end subroutine vtk_file_write_dofmap_coordinates
 
  subroutine vtk_file_write_dofmap_data(unit, dm)
    integer :: unit
    type(dofmap_t), intent(inout) :: dm
    integer :: i, j, k, l
 
    write(unit, fmt = '(A,I8)') 'POINT_DATA', size(dm%dof)
    write(unit, fmt = '(A,A,A,I8)') 'SCALARS ', 'dof_id', ' integer', 1
    write(unit, fmt = '(A)') 'LOOKUP_TABLE default'
 
    do i = 1, dm%msh%nelv
       do l = 1, dm%Xh%lz
          do k = 1, dm%Xh%ly
             do j = 1, dm%Xh%lx
                write(unit, fmt = '(I8)') real(dm%dof(j,k,l,i), dp)
             end do
          end do
       end do
    end do
 
    write(unit, fmt = '(A,A,A,I8)') 'SCALARS ', 'shared_dof', ' integer', 1
    write(unit, fmt = '(A)') 'LOOKUP_TABLE default'
 
    do i = 1, dm%msh%nelv
       do l = 1, dm%Xh%lz
          do k = 1, dm%Xh%ly
             do j = 1, dm%Xh%lx
                if (dm%shared_dof(j,k,l,i)) then
                   write(unit, fmt = '(I8)') 1
                else
                   write(unit, fmt = '(I8)') 0
                end if
             end do
          end do
       end do
    end do
 
  end subroutine vtk_file_write_dofmap_data
 
  subroutine vtk_file_write_tet_mesh(unit, tet_msh)
    integer :: unit
    type(tet_mesh_t), intent(inout) :: tet_msh
    integer, parameter :: npts = 4
    integer :: i, j, vtk_type
    integer :: pt_id, pt_lid
    integer :: tet_pts(npts)
    type(htable_i4_t) :: lid
 
    ! Dump coordinates
    write(unit, fmt = '(A,I8,A)') 'POINTS', tet_msh%msh%mpts, ' double'
    do i = 1, tet_msh%msh%mpts
       write(unit, fmt = '(F15.8,F15.8,F15.8)') &
            real(tet_msh%msh%points(i)%x, dp)
    end do
 
    ! A tetrahedron's vertices point into the hexahedral mesh's point list but
    ! carry no element and corner of their own, so unlike the other writers
    ! this one cannot read pt_lid and needs its own global->local table.
    ! @note Periodic meshes hold the merged id twice, once per side; the first
    ! occurrence wins here, as it did in the mesh's own table
    call lid%init(tet_msh%msh%mpts, i)
    do i = 1, tet_msh%msh%mpts
       pt_id = tet_msh%msh%points(i)%id()
       if (lid%get(pt_id, pt_lid) .gt. 0) then
          pt_lid = i
          call lid%set(pt_id, pt_lid)
       end if
    end do
 
    ! Dump cells
    write(unit, fmt = '(A,I8,I8)') 'CELLS', tet_msh%nelv, tet_msh%nelv*(npts+1)
    do i = 1, tet_msh%nelv
       do j = 1, npts
          pt_id = tet_msh%el(i)%pts(j)%p%id()
          if (lid%get(pt_id, pt_lid) .gt. 0) then
             call neko_error('Tetrahedron vertex is not a mesh point')
          end if
          tet_pts(j) = pt_lid - 1
       end do
       write(unit, fmt = '(I8,8I8)') npts, (tet_pts(j), j = 1, npts)
    end do
 
    call lid%free()
 
    ! Dump cell type for each element
    write(unit, fmt = '(A,I8)') 'CELL_TYPES', tet_msh%nelv
    vtk_type = 10
    do i = 1, tet_msh%nelv
       write(unit, fmt = '(I2)') vtk_type
    end do
 
  end subroutine vtk_file_write_tet_mesh
 
  subroutine vtk_file_write_tri_mesh(unit, tri_msh)
    integer :: unit
    type(tri_mesh_t), intent(inout) :: tri_msh
    integer, parameter :: npts = 3
    integer :: i, j, vtk_type
 
    ! Dump coordinates
    write(unit, fmt = '(A,I8,A)') 'POINTS', tri_msh%mpts, ' double'
    do i = 1, tri_msh%mpts
       write(unit, fmt = '(F15.8,F15.8,F15.8)') real(tri_msh%points(i)%x, dp)
    end do
 
    ! Dump cells
    write(unit, fmt = '(A,I8,I8)') 'CELLS', tri_msh%nelv, tri_msh%nelv*(npts+1)
    j = 0
    do i = 1, tri_msh%nelv
       write(unit, fmt = '(I8,8I8)') npts, &
            (tri_msh%el(i)%pts(j)%p%id() - 1, j = 1, npts)
    end do
 
    ! Dump cell type for each element
    write(unit, fmt = '(A,I8)') 'CELL_TYPES', tri_msh%nelv
    vtk_type = 5
    do i = 1, tri_msh%nelv
       write(unit, fmt = '(I2)') vtk_type
    end do
 
  end subroutine vtk_file_write_tri_mesh
 
end module vtk_file