source: branches/HeuristicLab.ExpressionGenerator/HeuristicLab.ExpressionGenerator/3.4/ExpressionTemplate.cs @ 14485

Last change on this file since 14485 was 14485, checked in by gkronber, 4 years ago

minor changes made while reviewing

File size: 3.6 KB
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1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2016 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
4 *
5 * This file is part of HeuristicLab.
6 *
7 * HeuristicLab is free software: you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation, either version 3 of the License, or
10 * (at your option) any later version.
11 *
12 * HeuristicLab is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
19 */
20#endregion
21
22using System;
23using System.Collections.Generic;
24using System.Linq;
25using HeuristicLab.Core;
26using HeuristicLab.Random;
27
28namespace HeuristicLab.ExpressionGenerator {
29  public abstract class ExpressionTemplate {
30    private List<Tuple<Expression, double>> arguments;
31    private readonly Func<IEnumerable<double>, double> transform;
32    public string Label { get; set; }
33
34    protected Expression Instantiate(string name, IRandom random, int n, bool sampleWithRepetition = false) {
35      var weights = arguments.Select(x => x.Item2);
36      var args = sampleWithRepetition
37       ? arguments.SampleProportional(random, n, weights).Select(x => x.Item1)
38       : arguments.SampleProportionalWithoutRepetition(random, n, weights).Select(x => x.Item1);
39      var func = Expression.Function(name, transform, args);
40      func.Label = Label;
41      return func;
42    }
43
44    public abstract Expression Instantiate(string name, IRandom random, bool sampleWithRepetition = false);
45
46    protected ExpressionTemplate(Func<IEnumerable<double>, double> transform) {
47      this.transform = transform;
48    }
49
50    public void AddArgument(Expression expression, double weight = 1d) {
51      arguments = arguments ?? new List<Tuple<Expression, double>>();
52      arguments.Add(Tuple.Create(expression, weight));
53    }
54
55    public void AddArguments(IEnumerable<Expression> expressions) {
56      arguments = arguments ?? new List<Tuple<Expression, double>>();
57      arguments.AddRange(expressions.Select(x => Tuple.Create(x, 1d)));
58    }
59
60    public void AddArguments(IEnumerable<Expression> expressions, IEnumerable<double> weights) {
61      arguments = arguments ?? new List<Tuple<Expression, double>>();
62      arguments.AddRange(expressions.Zip(weights, Tuple.Create));
63    }
64  }
65
66  public class RandomArityTemplate : ExpressionTemplate {
67    private readonly IRandom arityDistribution;
68
69    public RandomArityTemplate(Func<IEnumerable<double>, double> transform, IRandom arityDistribution) : base(transform) {
70      this.arityDistribution = arityDistribution;
71    }
72
73    public override Expression Instantiate(string name, IRandom random, bool sampleWithRepetition = false) {
74      var arity = (int)Math.Round(arityDistribution.NextDouble());
75      return Instantiate(name, random, arity, sampleWithRepetition);
76    }
77  }
78
79  public class FixedArityTemplate : ExpressionTemplate {
80    private readonly int arity;
81    public FixedArityTemplate(Func<IEnumerable<double>, double> transform, int arity) : base(transform) {
82      this.arity = arity;
83    }
84
85    public override Expression Instantiate(string name, IRandom random, bool sampleWithRepetition = false) {
86      return Instantiate(name, random, arity, sampleWithRepetition);
87    }
88  }
89}
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