#region License Information /* HeuristicLab * Copyright (C) 2002-2016 Heuristic and Evolutionary Algorithms Laboratory (HEAL) * * This file is part of HeuristicLab. * * HeuristicLab 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. * * HeuristicLab 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 HeuristicLab. If not, see . */ #endregion using System; using System.Collections.Generic; namespace HeuristicLab.Algorithms.DataAnalysis { internal static class TSNEUtils { internal static void ForEach(this IEnumerable sequence, Action action) { if (sequence == null) return; if (action == null) throw new ArgumentException("Null Action can not be performed"); var i = 0; foreach (var item in sequence) { action(i, item); i++; } } internal static void Swap(this IList list, int indexA, int indexB) { var tmp = list[indexA]; list[indexA] = list[indexB]; list[indexB] = tmp; } private static int Partition(this IList list, int left, int right, int pivotindex, IComparer comparer) { var pivotValue = list[pivotindex]; list.Swap(pivotindex, right); var storeIndex = left; for (var i = left; i < right; i++) if (comparer.Compare(list[i], pivotValue) < 0) list.Swap(storeIndex++, i); list.Swap(right, storeIndex); return storeIndex; } /// /// Quick-Sort based partial ascending sorting /// [0,left-1] not changed; /// [left, n] elements are smaller than or equal to list[n] /// [n, right] elements are grater than or equal to list[n] /// [right, list.Count[ not changed; /// /// /// list that shall be partially sorted /// left index of sorted list part /// right index of sorted list part /// index around which the partial sorting occures /// comparer for list elemnts /// internal static void PartialSort(this IList list, int left, int right, int n, IComparer comparer) { while (true) { if (left == right) return; var pivotindex = left + (int) Math.Floor(new System.Random().Next() % (right - (double) left + 1)); pivotindex = list.Partition(left, right, pivotindex, comparer); if (n == pivotindex) return; if (n < pivotindex) right = pivotindex - 1; else left = pivotindex + 1; } } } }