#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; using System.Globalization; using System.Linq; using System.Text; using HeuristicLab.Common; using HeuristicLab.Core; using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding; using HeuristicLab.Persistence.Default.CompositeSerializers.Storable; namespace HeuristicLab.Problems.DataAnalysis.Symbolic { /// /// Formats mathematical expressions in infix form. E.g. x1 * (3.0 * x2 + x3) /// [StorableClass] [Item("Infix Symbolic Expression Tree Formatter", "A string formatter that converts symbolic expression trees to infix expressions.")] public sealed class InfixExpressionFormatter : NamedItem, ISymbolicExpressionTreeStringFormatter { [StorableConstructor] private InfixExpressionFormatter(bool deserializing) : base(deserializing) { } private InfixExpressionFormatter(InfixExpressionFormatter original, Cloner cloner) : base(original, cloner) { } public InfixExpressionFormatter() : base() { Name = ItemName; Description = ItemDescription; } public override IDeepCloneable Clone(Cloner cloner) { return new InfixExpressionFormatter(this, cloner); } public string Format(ISymbolicExpressionTree symbolicExpressionTree) { // skip root and start symbols StringBuilder strBuilder = new StringBuilder(); FormatRecursively(symbolicExpressionTree.Root.GetSubtree(0).GetSubtree(0), strBuilder); return strBuilder.ToString(); } private void FormatRecursively(ISymbolicExpressionTreeNode node, StringBuilder strBuilder) { if (node.SubtreeCount > 1) { var token = GetToken(node.Symbol); if (token == "+" || token == "-" || token == "OR" || token == "XOR") { strBuilder.Append("("); FormatRecursively(node.Subtrees.First(), strBuilder); foreach (var subtree in node.Subtrees.Skip(1)) { strBuilder.Append(" ").Append(token).Append(" "); FormatRecursively(subtree, strBuilder); } strBuilder.Append(")"); } else if (token == "*" || token == "/" || token == "AND") { strBuilder.Append("("); FormatRecursively(node.Subtrees.First(), strBuilder); foreach (var subtree in node.Subtrees.Skip(1)) { strBuilder.Append(" ").Append(token).Append(" "); FormatRecursively(subtree, strBuilder); } strBuilder.Append(")"); } else { // function with multiple arguments strBuilder.Append(token).Append("("); FormatRecursively(node.Subtrees.First(), strBuilder); foreach (var subtree in node.Subtrees.Skip(1)) { strBuilder.Append(", "); FormatRecursively(subtree, strBuilder); } strBuilder.Append(")"); } } else if (node.SubtreeCount == 1) { var token = GetToken(node.Symbol); if (token == "-" || token == "NOT") { strBuilder.Append("(").Append(token).Append("("); FormatRecursively(node.GetSubtree(0), strBuilder); strBuilder.Append("))"); } else if (token == "/") { strBuilder.Append("1/"); FormatRecursively(node.GetSubtree(0), strBuilder); } else if (token == "+" || token == "*") { FormatRecursively(node.GetSubtree(0), strBuilder); } else { // function with only one argument strBuilder.Append(token).Append("("); FormatRecursively(node.GetSubtree(0), strBuilder); strBuilder.Append(")"); } } else { // no subtrees if (node.Symbol is LaggedVariable) { var varNode = node as LaggedVariableTreeNode; if (!varNode.Weight.IsAlmost(1.0)) { strBuilder.Append("("); strBuilder.AppendFormat(CultureInfo.InvariantCulture, "{0}", varNode.Weight); strBuilder.Append("*"); } strBuilder.Append("LAG("); if (varNode.VariableName.Contains("'")) { strBuilder.AppendFormat("\"{0}\"", varNode.VariableName); } else { strBuilder.AppendFormat("'{0}'", varNode.VariableName); } strBuilder.Append(", ") .AppendFormat(CultureInfo.InvariantCulture, "{0}", varNode.Lag) .Append(")"); } else if (node.Symbol is Variable) { var varNode = node as VariableTreeNode; if (!varNode.Weight.IsAlmost(1.0)) { strBuilder.Append("("); strBuilder.AppendFormat(CultureInfo.InvariantCulture, "{0}", varNode.Weight); strBuilder.Append("*"); } if (varNode.VariableName.Contains("'")) { strBuilder.AppendFormat("\"{0}\"", varNode.VariableName); } else { strBuilder.AppendFormat("'{0}'", varNode.VariableName); } if (!varNode.Weight.IsAlmost(1.0)) { strBuilder.Append(")"); } } else if (node.Symbol is Constant) { var constNode = node as ConstantTreeNode; if (constNode.Value >= 0.0) strBuilder.AppendFormat(CultureInfo.InvariantCulture, "{0}", constNode.Value); else strBuilder.AppendFormat(CultureInfo.InvariantCulture, "({0})", constNode.Value); // (-1 } } } private string GetToken(ISymbol symbol) { var tok = InfixExpressionParser.knownSymbols.GetBySecond(symbol).SingleOrDefault(); if (tok == null) throw new ArgumentException(string.Format("Unknown symbol {0} found.", symbol.Name)); return tok; } } }