2 * Copyright (C) 2012-2022 Euclid Science Ground Segment
4 * This library is free software; you can redistribute it and/or modify it under
5 * the terms of the GNU Lesser General Public License as published by the Free
6 * Software Foundation; either version 3.0 of the License, or (at your option)
9 * This library is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
11 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
14 * You should have received a copy of the GNU Lesser General Public License
15 * along with this library; if not, write to the Free Software Foundation, Inc.,
16 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24#include "SOM/ImplTools.h"
32namespace UMatrix_impl {
34std::map<UMatrixType, std::function<double(const std::vector<double>&)>> type_func_map{
36 [](const std::vector<double>& dist_list) { return *std::min_element(dist_list.begin(), dist_list.end()); }},
38 [](const std::vector<double>& dist_list) { return *std::max_element(dist_list.begin(), dist_list.end()); }},
39 {UMatrixType::MEAN, [](const std::vector<double>& dist_list) {
40 return std::accumulate(dist_list.begin(), dist_list.end(), 0.) / dist_list.size();
45template <typename DistFunc>
46UMatrix computeUMatrix(const SOM<DistFunc>& som, UMatrixType type) {
50 auto size = som.getSize();
51 UMatrix result = UMatrix(ImplTools::indexAxis("X", size.first), ImplTools::indexAxis("Y", size.second));
53 // Chose the method used for computing the u-matrix values
54 auto type_func = UMatrix_impl::type_func_map.at(type);
56 // Go through the SOM cells and compute the u-matrix cells
57 for (std::size_t x = 0; x < size.first; ++x) {
58 for (std::size_t y = 0; y < size.second; ++y) {
60 // Go through the neighbor cells and create the vector with the distances
61 std::vector<double> dist_list{};
62 for (int i = int(x) - 1; i <= (int)x + 1; ++i) {
63 for (int j = int(y) - 1; j <= (int)y + 1; ++j) {
65 // Check that we are not at the cell itself
66 if (i == (int)x && j == (int)y) {
69 // Double check that we are not outside of the SOM borders
70 if (i < 0 || i == (int)size.first || j < 0 || j == (int)size.second) {
76 dist_list.push_back(dist_func.distance(sxy.begin(), sxy.end(), sij.begin()));
80 // Populate the u-matrix cell
81 result(x, y) = type_func(dist_list);