boundary.hpp

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/*
 * Copyright (C) 2020-2026 The ESPResSo project
 *
 * This file is part of ESPResSo.
 *
 * ESPResSo is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * ESPResSo is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#pragma once
 
#include "types_conversion.hpp"
 
#include <walberla_bridge/LatticeWalberla.hpp>
 
#include <utils/Vector.hpp>
 
#include <cassert>
#include <cstddef>
#include <iterator>
#include <vector>
 
namespace walberla {
 
inline std::vector<Utils::Vector3d>
fill_3D_vector_array(std::vector<double> const &vec_flat,
                     Utils::Vector3i const &grid_size) {
  auto const n_grid_points =
      static_cast<std::size_t>(Utils::product(grid_size));
  assert(vec_flat.size() == 3u * n_grid_points or vec_flat.size() == 3u);
  std::vector<Utils::Vector3d> output_vector;
  output_vector.reserve(3u * n_grid_points);
 
  auto const vec_begin = std::begin(vec_flat);
  auto const vec_end = std::end(vec_flat);
  if (vec_flat.size() == 3u) {
    auto const uniform_vector = Utils::Vector3d(vec_begin, vec_end);
    output_vector.assign(n_grid_points, uniform_vector);
  } else {
    output_vector.reserve(n_grid_points);
    for (auto it = vec_begin; it < vec_end; it += 3u) {
      output_vector.emplace_back(it, it + 3u);
    }
  }
 
  return output_vector;
}
 
inline std::vector<double>
fill_3D_scalar_array(std::vector<double> const &vec_flat,
                     Utils::Vector3i const &grid_size) {
  auto const n_grid_points =
      static_cast<std::size_t>(Utils::product(grid_size));
  assert(vec_flat.size() == n_grid_points or vec_flat.size() == 1u);
  std::vector<double> output_vector;
  output_vector.reserve(n_grid_points);
 
  auto const vec_begin = std::begin(vec_flat);
  auto const vec_end = std::end(vec_flat);
  if (vec_flat.size() == 1u) {
    auto const uniform_value = vec_flat[0];
    output_vector.assign(n_grid_points, uniform_value);
  } else {
    output_vector.assign(vec_begin, vec_end);
  }
 
  return output_vector;
}
 
template <class BoundaryModel, class DataType>
void set_boundary_from_grid(BoundaryModel &boundary,
                            LatticeWalberla const &lattice,
                            std::vector<int> const &raster_flat,
                            std::vector<DataType> const &data_flat) {
 
  auto const &conv = es2walberla<DataType, typename BoundaryModel::value_type>;
  auto const grid_size = lattice.get_grid_dimensions();
  auto const gl = static_cast<int>(lattice.get_ghost_layers());
  assert(raster_flat.size() ==
         static_cast<std::size_t>(Utils::product(grid_size)));
  auto const n_y = static_cast<std::size_t>(grid_size[1]);
  auto const n_z = static_cast<std::size_t>(grid_size[2]);
 
  for (auto &block : *lattice.get_blocks()) {
    auto const [size_i, size_j, size_k] = boundary.block_dims(block);
    auto const offset = lattice.get_block_corner(block, true);
    // Get field data which knows about the indices
    // In the loop, i,j,k are in block-local coordinates
    for (int i = -gl; i < size_i + gl; ++i) {
      for (int j = -gl; j < size_j + gl; ++j) {
        for (int k = -gl; k < size_k + gl; ++k) {
          auto const node = offset + Utils::Vector3i{{i, j, k}};
          auto const idx = (node + grid_size) % grid_size;
          auto const index = static_cast<std::size_t>(idx[0]) * n_y * n_z +
                             static_cast<std::size_t>(idx[1]) * n_z +
                             static_cast<std::size_t>(idx[2]);
          if (raster_flat[index]) {
            auto const &value = data_flat[index];
            auto const bc = BlockAndCell{&block, Cell(i, j, k)};
            boundary.set_node_value_at_boundary(node, conv(value), bc);
          }
        }
      }
    }
  }
}
 
} // namespace walberla