[14505] | 1 | #region License Information
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| 2 | /* HeuristicLab
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| 3 | * Copyright (C) 2002-2016 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.Core;
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| 26 | using HeuristicLab.Random;
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| 27 |
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| 28 | namespace HeuristicLab.ExpressionGenerator {
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| 29 | public static class ExpressionGenerator {
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| 30 | public static IEnumerable<Expression> GenerateRandomDistributedVariables(int numberOfVariables, string variablePrefix, IRandom randomDistribution) {
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| 31 | return Enumerable.Range(1, numberOfVariables).Select(x => Expression.RandomVariable(string.Format("{0}{1}", variablePrefix, x), randomDistribution));
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| 32 | }
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| 33 |
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| 34 | public static Expression Polynomial(IRandom uniformRandom, Expression[] variables, bool useLog, bool useExp) {
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| 35 | var sumTemplate = new RandomArityTemplate(Sum, new UniformDistributedRandom(uniformRandom, 1, variables.Length)) { Label = "+" };
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| 36 | sumTemplate.AddArguments(variables);
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| 37 |
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| 38 | var productTemplate = new RandomArityTemplate(Product, new UniformDistributedRandom(uniformRandom, 1, variables.Length)) { Label = "*" };
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| 39 | productTemplate.AddArguments(variables);
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| 40 |
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[14510] | 41 | const int count = 10; // how many instances of each template should be produce?
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[14505] | 42 | int i = 1;
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| 43 |
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| 44 | var logTemplate = new FixedArityTemplate(Log, 1) { Label = "log" };
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| 45 | logTemplate.AddArguments(variables);
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[14510] | 46 | logTemplate.AddArguments(Enumerable.Range(1, count).Select(x => sumTemplate.Instantiate(string.Format("sum{0}", i++), uniformRandom)));
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[14505] | 47 |
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| 48 | var expTemplate = new FixedArityTemplate(Exp, 1) { Label = "exp" };
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| 49 | expTemplate.AddArguments(variables);
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[14510] | 50 | expTemplate.AddArguments(Enumerable.Range(1, count).Select(x => productTemplate.Instantiate(string.Format("prod{0}", i++), uniformRandom)));
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[14505] | 51 |
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[14510] | 52 | var inverseTemplate = new FixedArityTemplate(Division, 1) { Label = "/" };
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[14505] | 53 | inverseTemplate.AddArguments(variables);
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[14510] | 54 | inverseTemplate.AddArguments(Enumerable.Range(1, count).Select(x => sumTemplate.Instantiate(string.Format("sum{0}", i++), uniformRandom)));
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| 55 | inverseTemplate.AddArguments(Enumerable.Range(1, count).Select(x => productTemplate.Instantiate(string.Format("prod{0}", i++), uniformRandom)));
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| 56 | inverseTemplate.AddArguments(Enumerable.Range(1, count).Select(x => logTemplate.Instantiate(string.Format("log{0}", i++), uniformRandom)));
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| 57 | inverseTemplate.AddArguments(Enumerable.Range(1, count).Select(x => expTemplate.Instantiate(string.Format("exp{0}", i++), uniformRandom)));
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[14505] | 58 |
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| 59 | var template = new RandomArityTemplate(Sum, new UniformDistributedRandom(uniformRandom, 2, count)) { Label = "+" };
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| 60 | template.AddArguments(variables);
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| 61 | template.AddArguments(Enumerable.Range(1, count).Select(x => logTemplate.Instantiate(string.Format("log{0}", i++), uniformRandom)));
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| 62 | template.AddArguments(Enumerable.Range(1, count).Select(x => expTemplate.Instantiate(string.Format("exp{0}", i++), uniformRandom)));
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| 63 | template.AddArguments(Enumerable.Range(1, count).Select(x => inverseTemplate.Instantiate(string.Format("inv{0}", i++), uniformRandom)));
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| 64 |
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| 65 | return template.Instantiate("polynomial", uniformRandom);
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| 66 | }
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| 67 |
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| 68 | #region static functions
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| 69 | private static double Sum(IEnumerable<double> args) {
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| 70 | return args.Sum();
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| 71 | }
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| 72 |
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| 73 | private static double Product(IEnumerable<double> args) {
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| 74 | return args.Aggregate((x, y) => x * y);
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| 75 | }
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| 76 |
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| 77 | private static double Division(IEnumerable<double> args) {
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| 78 | if (args.Count() == 1)
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| 79 | return 1 / args.First();
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| 80 |
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| 81 | return args.Aggregate((x, y) => x / y);
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| 82 | }
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| 83 |
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| 84 | private static double Subtraction(IEnumerable<double> args) {
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| 85 | if (args.Count() == 1)
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| 86 | return -args.First();
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| 87 |
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| 88 | return args.Aggregate((x, y) => x - y);
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| 89 | }
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| 90 |
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| 91 | private static double Exp(IEnumerable<double> args) {
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| 92 | return Math.Exp(args.Single());
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| 93 | }
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| 94 |
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| 95 | private static double Log(IEnumerable<double> args) {
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| 96 | return Math.Log(args.Single());
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| 97 | }
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| 98 |
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| 99 | private static double Square(IEnumerable<double> args) {
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| 100 | var v = args.Single();
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| 101 | return v * v;
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| 102 | }
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| 103 | #endregion
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| 104 | }
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| 105 | }
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