1 | #region License Information
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2 | /* HeuristicLab
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3 | * Copyright (C) 2002-2010 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
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4 | *
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5 | * This file is part of HeuristicLab.
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6 | *
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7 | * HeuristicLab is free software: you can redistribute it and/or modify
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8 | * it under the terms of the GNU General Public License as published by
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9 | * the Free Software Foundation, either version 3 of the License, or
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10 | * (at your option) any later version.
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11 | *
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12 | * HeuristicLab is distributed in the hope that it will be useful,
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13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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15 | * GNU General Public License for more details.
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16 | *
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17 | * You should have received a copy of the GNU General Public License
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18 | * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
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19 | */
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20 | #endregion
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21 |
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22 | using System;
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23 | using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
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24 | using HeuristicLab.Data;
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25 | using System.Collections.Generic;
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26 |
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27 | namespace HeuristicLab.Problems.ArtificialAnt {
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28 | public class AntInterpreter {
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29 | public int MaxTimeSteps { get; set; }
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30 | public int FoodEaten { get; set; }
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31 | private BoolMatrix world;
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32 | public BoolMatrix World {
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33 | get { return world; }
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34 | set {
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35 | // create a clone of the world because the ant will remove the food items it can find.
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36 | world = (BoolMatrix)value.Clone();
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37 | CountFoodItems();
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38 | }
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39 | }
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40 |
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41 | private SymbolicExpressionTree expression;
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42 | public SymbolicExpressionTree Expression {
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43 | get { return expression; }
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44 | set {
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45 | expression = value;
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46 | }
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47 | }
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48 | public int ElapsedTime { get; set; }
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49 | private int currentDirection;
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50 | private int currentAntLocationRow;
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51 | private int currentAntLocationColumn;
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52 | private int nFoodItems;
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53 | private Stack<SymbolicExpressionTreeNode> nodeStack = new Stack<SymbolicExpressionTreeNode>();
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54 |
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55 | private void CountFoodItems() {
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56 | nFoodItems = 0;
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57 | for (int i = 0; i < World.Rows; i++) {
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58 | for (int j = 0; j < World.Columns; j++) {
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59 | if (World[i, j]) nFoodItems++;
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60 | }
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61 | }
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62 | }
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63 |
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64 | public void AntLocation(out int row, out int column) {
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65 | row = currentAntLocationRow;
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66 | column = currentAntLocationColumn;
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67 | }
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68 |
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69 | public int AntDirection {
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70 | get { return currentDirection; }
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71 | }
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72 |
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73 | public void Run() {
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74 | while (ElapsedTime < MaxTimeSteps && FoodEaten < nFoodItems) {
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75 | Step();
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76 | }
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77 | }
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78 |
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79 | public void Step() {
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80 | // expression evaluated completly => start at root again
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81 | if (nodeStack.Count == 0)
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82 | nodeStack.Push(Expression.Root.SubTrees[0]);
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83 | var currentNode = nodeStack.Pop();
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84 | if (currentNode.Symbol is Left) {
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85 | currentDirection = (currentDirection + 3) % 4;
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86 | ElapsedTime++;
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87 | } else if (currentNode.Symbol is Right) {
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88 | currentDirection = (currentDirection + 1) % 4;
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89 | ElapsedTime++;
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90 | } else if (currentNode.Symbol is Move) {
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91 | MoveAntForward();
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92 | if (World[currentAntLocationRow, currentAntLocationColumn])
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93 | FoodEaten++;
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94 | World[currentAntLocationRow, currentAntLocationColumn] = false;
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95 | ElapsedTime++;
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96 | } else if (currentNode.Symbol is IfFoodAhead) {
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97 | int nextAntLocationRow;
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98 | int nextAntLocationColumn;
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99 | NextField(out nextAntLocationRow, out nextAntLocationColumn);
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100 | if (World[nextAntLocationRow, nextAntLocationColumn]) {
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101 | nodeStack.Push(currentNode.SubTrees[0]);
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102 | } else {
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103 | nodeStack.Push(currentNode.SubTrees[1]);
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104 | }
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105 | } else if (currentNode.Symbol is Prog2) {
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106 | nodeStack.Push(currentNode.SubTrees[1]);
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107 | nodeStack.Push(currentNode.SubTrees[0]);
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108 | return;
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109 | } else if (currentNode.Symbol is Prog3) {
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110 | nodeStack.Push(currentNode.SubTrees[2]);
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111 | nodeStack.Push(currentNode.SubTrees[1]);
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112 | nodeStack.Push(currentNode.SubTrees[0]);
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113 | return;
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114 | } else {
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115 | throw new InvalidOperationException(currentNode.Symbol.ToString());
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116 | }
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117 | }
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118 |
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119 | private void MoveAntForward() {
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120 | NextField(out currentAntLocationRow, out currentAntLocationColumn);
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121 | }
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122 |
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123 | private void NextField(out int nextAntLocationRow, out int nextAntLocationColumn) {
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124 | switch (currentDirection) {
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125 | case 0:
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126 | nextAntLocationColumn = (currentAntLocationColumn + 1) % World.Columns; // EAST
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127 | nextAntLocationRow = currentAntLocationRow;
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128 | break;
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129 | case 1:
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130 | nextAntLocationRow = (currentAntLocationRow + 1) % World.Rows; // SOUTH
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131 | nextAntLocationColumn = currentAntLocationColumn;
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132 | break;
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133 | case 2:
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134 | nextAntLocationColumn = (currentAntLocationColumn + World.Columns - 1) % World.Columns; // WEST
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135 | nextAntLocationRow = currentAntLocationRow;
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136 | break;
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137 | case 3:
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138 | nextAntLocationRow = (currentAntLocationRow + World.Rows - 1) % World.Rows; // NORTH
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139 | nextAntLocationColumn = currentAntLocationColumn;
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140 | break;
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141 | default:
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142 | throw new InvalidOperationException();
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143 | }
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144 | }
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145 | }
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146 | }
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