computational_domain_3d.f90

program computational_domain_3d
  use m_a3_all

  implicit none

  integer    :: n_cell   = 4    ! Boxes contain n_cell^dim cells
  real(dp)   :: dr       = 1.0_dp ! Coarse grid spacing
  integer    :: n_var_cc = 1      ! Number of cell-centered variables
  integer    :: n_var_fc = 0      ! Number of face-centered variables
  type(a3_t) :: tree             ! Will contain the quad/octree grid

  integer, parameter :: n_boxes = 2 ! How many boxes to add
  integer :: ix_list(3, n_boxes)                ! Spatial indices of boxes
  integer :: nb_list(a3_num_neighbors, n_boxes) ! Neighbor information

  ! Create mesh 1: two boxes along x-direction
  ix_list(:, 1) = [1, 1, 1]     ! Box 1 at [1, 1, 1]
  ix_list(:, 2) = [2, 1, 1]     ! Box 2 at [2, 1, 1]

  call a3_init(tree, n_cell, n_var_cc, n_var_fc, dr)
  call a3_set_base(tree, n_boxes, ix_list)
  call a3_write_vtk(tree, "computational_domain_3d_1", dir="output")
  call a3_destroy(tree)

  ! Create mesh 2: two boxes along y-direction
  ix_list(:, 1) = [1, 1, 1]     ! Box 1 at [1, 1, 1]
  ix_list(:, 2) = [1, 2, 1]     ! Box 2 at [1, 2, 1]

  call a3_init(tree, n_cell, n_var_cc, n_var_fc, dr)
  call a3_set_base(tree, n_boxes, ix_list)
  call a3_write_vtk(tree, "computational_domain_3d_2", dir="output")
  call a3_destroy(tree)

  ! Create mesh 3: Two boxes along x-direction that are fully periodic
  ix_list(:, 1) = [1, 1, 1]     ! Box 1 at [1, 1, 1]
  ix_list(:, 2) = [2, 1, 1]     ! Box 2 at [2, 1, 1]

  nb_list(:, :) = af_no_box       ! Start with default value
  nb_list(a3_neighb_lowx, 1) = 2 ! Box 1's lower x-neighbor is box 2
  nb_list(a3_neighb_lowy, 1) = 1 ! Box 1 is periodic in y-direction
  nb_list(a3_neighb_lowy, 2) = 2 ! Box 2 is periodic in y-direction
  nb_list(a3_neighb_lowz, 1) = 1
  nb_list(a3_neighb_lowz, 2) = 2

  call a3_init(tree, n_cell, n_var_cc, n_var_fc, dr)
  call a3_set_base(tree, n_boxes, ix_list, nb_list)
  call a3_write_vtk(tree, "computational_domain_3d_3", dir="output")
  call a3_destroy(tree)

end program computational_domain_3d