Changeset 12024 for branches/HeuristicLab.Problems.GrammaticalOptimization/HeuristicLab.Problems.GrammaticalOptimization.SymbReg

Timestamp:

02/17/15 16:03:49 (10 years ago)

Author:

gkronber

Message:

#2283: changed handling of inverse expressions in transformation of expressions to canonical form

Location:

branches/HeuristicLab.Problems.GrammaticalOptimization/HeuristicLab.Problems.GrammaticalOptimization.SymbReg

Files:

• ExpressionCompiler.cs (modified) (2 diffs)
• SymbolicRegressionProblem.cs (modified) (2 diffs)

branches/HeuristicLab.Problems.GrammaticalOptimization/HeuristicLab.Problems.GrammaticalOptimization.SymbReg/ExpressionCompiler.cs

@@ -95 +95 @@
       if (f != null) factors.Add(f);
       var curSy = CurSy();
-      while (curSy == '*' || curSy == '%' || curSy == '/') { // division and protected division symbols are handled in the same way
+      while (curSy == '*' || curSy == '%') { // division and protected division symbols are handled in the same way
         if (curSy == '*') {
           NewSy();
@@ -135 +135 @@
         r = variables[varIdx];
         NewSy();
-      } else if (curSy == '|') {
-        // pipe symbol is used in the expressionextender to represent constant one (|/x). 
+      } else if (curSy == '/') {
+        // /-symbol used in the expressionextender to represent inverse (1/x). 
         // this is necessary because we also use symbols 0..9 as indices for ERCs
-        r = 1.0;
         NewSy();
+        r = 1.0 / Fact(variables, constants);
       } else if (curSy >= '0' && curSy <= '9') {
         int o = (byte)curSy - (byte)'0';

branches/HeuristicLab.Problems.GrammaticalOptimization/HeuristicLab.Problems.GrammaticalOptimization.SymbReg/SymbolicRegressionProblem.cs

@@ -126 +126 @@
 
     public double Evaluate(string sentence) {
+      var extender = new ExpressionExtender();
+      sentence = extender.CanonicalRepresentation(sentence);
       if (useConstantOpt)
         return OptimizeConstantsAndEvaluate(sentence);
       else {
-        var extender = new ExpressionExtender();
 
         Debug.Assert(SimpleEvaluate(sentence) == SimpleEvaluate(extender.CanonicalRepresentation(sentence)));
@@ -152 +153 @@
 
     public IEnumerable<Feature> GetFeatures(string phrase) {
+      // throw new NotImplementedException();
       phrase = CanonicalRepresentation(phrase);
-      return new Feature[] { new Feature(phrase, 1.0) };
+      return phrase.Split('+').Distinct().Select(t => new Feature(t, 1.0));
+      // return new Feature[] { new Feature(phrase, 1.0) };
     }