Changeset 10984 for trunk/sources

Timestamp:

06/11/14 14:02:11 (10 years ago)

Author:

gkronber

Message:

#2109: retry until a unique constant is sampled when creating constants in the GE symbolic regression grammar

File:

• trunk/sources/HeuristicLab.Problems.GrammaticalEvolution/Symbolic/GESymbolicExpressionGrammar.cs (modified) (1 diff)

trunk/sources/HeuristicLab.Problems.GrammaticalEvolution/Symbolic/GESymbolicExpressionGrammar.cs

@@ -77 +77 @@
       var constants = new List<Constant>(nConstants);
       for (int i = 0; i < nConstants; i++) {
-        var constVal = rand.NextDouble() * 20.0 - 10.0;
         var constant = new Constant();
-        constant.Name = string.Format("{0:0.000}", constVal);
-        constant.MinValue = constVal;
-        constant.MaxValue = constVal;
-        constant.ManipulatorSigma = 0.0;
-        constant.ManipulatorMu = 0.0;
-        constant.MultiplicativeManipulatorSigma = 0.0;
+        do {
+          var constVal = rand.NextDouble() * 20.0 - 10.0;
+          constant.Name = string.Format("{0:0.000}", constVal);
+          constant.MinValue = constVal;
+          constant.MaxValue = constVal;
+          constant.ManipulatorSigma = 0.0;
+          constant.ManipulatorMu = 0.0;
+          constant.MultiplicativeManipulatorSigma = 0.0;
+        } while (constants.Any(c => c.Name == constant.Name)); // unlikely, but it could happen that the same constant value is sampled twice. so we resample if necessary.
         constants.Add(constant);
       }