[12911] | 1 | #region License Information
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| 2 | /* HeuristicLab
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| 3 | * Copyright (C) 2002-2015 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 System.Collections.Generic;
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| 24 | using System.Linq;
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| 25 | using HeuristicLab.Data;
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| 26 | using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;
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| 27 |
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| 28 | namespace HeuristicLab.Problems.GeneticProgramming.ArtificialAnt {
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| 29 | public class Interpreter {
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| 30 |
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| 31 | public int MaxTimeSteps { get; private set; }
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| 32 | public int FoodEaten { get; private set; }
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| 33 | public BoolMatrix World { get; private set; }
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| 34 |
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| 35 | public ISymbolicExpressionTree Expression { get; private set; }
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| 36 |
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| 37 |
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| 38 | public int ElapsedTime { get; set; }
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| 39 | private int currentDirection;
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| 40 | private int currentAntLocationRow;
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| 41 | private int currentAntLocationColumn;
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| 42 | private int nFoodItems;
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| 43 | private Stack<ISymbolicExpressionTreeNode> nodeStack = new Stack<ISymbolicExpressionTreeNode>();
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| 44 |
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| 45 | public Interpreter(ISymbolicExpressionTree tree, BoolMatrix world, int maxTimeSteps) {
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| 46 | this.Expression = tree;
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| 47 | this.MaxTimeSteps = maxTimeSteps;
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| 48 | // create a clone of the world because the ant will remove the food items it can find.
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| 49 | World = (BoolMatrix)world.Clone();
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| 50 | CountFoodItems();
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| 51 | }
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| 52 |
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| 53 | private void CountFoodItems() {
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| 54 | nFoodItems = 0;
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| 55 | for (int i = 0; i < World.Rows; i++) {
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| 56 | for (int j = 0; j < World.Columns; j++) {
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| 57 | if (World[i, j]) nFoodItems++;
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| 58 | }
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| 59 | }
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| 60 | }
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| 61 |
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| 62 | public void AntLocation(out int row, out int column) {
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| 63 | row = currentAntLocationRow;
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| 64 | column = currentAntLocationColumn;
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| 65 | }
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| 66 |
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| 67 | public int AntDirection {
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| 68 | get { return currentDirection; }
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| 69 | }
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| 70 |
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| 71 | public void Run() {
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| 72 | while (ElapsedTime < MaxTimeSteps && FoodEaten < nFoodItems) {
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| 73 | Step();
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| 74 | }
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| 75 | }
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| 76 |
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| 77 | public void Step() {
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| 78 | // expression evaluated completly => start at root again
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| 79 | if (nodeStack.Count == 0) {
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| 80 | nodeStack.Push(Expression.Root.GetSubtree(0).GetSubtree(0));
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| 81 | }
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| 82 |
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| 83 | var currentNode = nodeStack.Pop();
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| 84 | if (currentNode.Symbol.Name == "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.Name == "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.Name == "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 | }
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| 96 | ElapsedTime++;
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| 97 | } else if (currentNode.Symbol.Name == "IfFoodAhead") {
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| 98 | int nextAntLocationRow;
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| 99 | int nextAntLocationColumn;
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| 100 | NextField(out nextAntLocationRow, out nextAntLocationColumn);
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| 101 | if (World[nextAntLocationRow, nextAntLocationColumn]) {
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| 102 | nodeStack.Push(currentNode.GetSubtree(0));
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| 103 | } else {
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| 104 | nodeStack.Push(currentNode.GetSubtree(1));
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| 105 | }
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| 106 | } else if (currentNode.Symbol.Name == "Prog2") {
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| 107 | nodeStack.Push(currentNode.GetSubtree(1));
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| 108 | nodeStack.Push(currentNode.GetSubtree(0));
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| 109 | } else if (currentNode.Symbol.Name == "Prog3") {
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| 110 | nodeStack.Push(currentNode.GetSubtree(2));
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| 111 | nodeStack.Push(currentNode.GetSubtree(1));
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| 112 | nodeStack.Push(currentNode.GetSubtree(0));
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| 113 | } else if (currentNode.Symbol is InvokeFunction) {
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| 114 | var invokeNode = currentNode as InvokeFunctionTreeNode;
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| 115 | var functionDefinition = (SymbolicExpressionTreeNode)FindMatchingFunction(invokeNode.Symbol.FunctionName).Clone();
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| 116 | var argumentCutPoints = (from node in functionDefinition.IterateNodesPrefix()
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| 117 | where node.Subtrees.Count() > 0
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| 118 | from subtree in node.Subtrees
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| 119 | where subtree is ArgumentTreeNode
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| 120 | select new { Parent = node, Argument = subtree.Symbol as Argument, ChildIndex = node.IndexOfSubtree(subtree) }).ToList();
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| 121 | foreach (var cutPoint in argumentCutPoints) {
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| 122 | cutPoint.Parent.RemoveSubtree(cutPoint.ChildIndex);
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| 123 | cutPoint.Parent.InsertSubtree(cutPoint.ChildIndex, (SymbolicExpressionTreeNode)invokeNode.GetSubtree(cutPoint.Argument.ArgumentIndex).Clone());
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| 124 | }
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| 125 | nodeStack.Push(functionDefinition.GetSubtree(0));
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| 126 | } else {
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| 127 | throw new InvalidOperationException(currentNode.Symbol.ToString());
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| 128 | }
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| 129 | }
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| 130 |
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| 131 | private void MoveAntForward() {
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| 132 | NextField(out currentAntLocationRow, out currentAntLocationColumn);
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| 133 | }
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| 134 |
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| 135 | private void NextField(out int nextAntLocationRow, out int nextAntLocationColumn) {
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| 136 | switch (currentDirection) {
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| 137 | case 0:
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| 138 | nextAntLocationColumn = (currentAntLocationColumn + 1) % World.Columns; // EAST
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| 139 | nextAntLocationRow = currentAntLocationRow;
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| 140 | break;
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| 141 | case 1:
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| 142 | nextAntLocationRow = (currentAntLocationRow + 1) % World.Rows; // SOUTH
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| 143 | nextAntLocationColumn = currentAntLocationColumn;
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| 144 | break;
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| 145 | case 2:
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| 146 | nextAntLocationColumn = (currentAntLocationColumn + World.Columns - 1) % World.Columns; // WEST
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| 147 | nextAntLocationRow = currentAntLocationRow;
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| 148 | break;
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| 149 | case 3:
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| 150 | nextAntLocationRow = (currentAntLocationRow + World.Rows - 1) % World.Rows; // NORTH
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| 151 | nextAntLocationColumn = currentAntLocationColumn;
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| 152 | break;
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| 153 | default:
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| 154 | throw new InvalidOperationException();
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| 155 | }
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| 156 | }
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| 157 |
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| 158 |
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| 159 | private SymbolicExpressionTreeNode FindMatchingFunction(string name) {
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| 160 | foreach (var defunBranch in Expression.Root.Subtrees.OfType<DefunTreeNode>()) {
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| 161 | if (defunBranch.FunctionName == name) return defunBranch;
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| 162 | }
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| 163 | throw new ArgumentException("Function definition for " + name + " not found.");
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| 164 | }
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| 165 | }
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| 166 | }
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