Changeset 17800

Timestamp:

12/22/20 12:49:01 (4 years ago)

Author:

gkronber

Message:

#3073: fixed bug in derivation of power function

File:

• branches/3073_IA_constraint_splitting/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Converters/DerivativeCalculator.cs (modified) (1 diff)

branches/3073_IA_constraint_splitting/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Converters/DerivativeCalculator.cs

@@ -151 +151 @@
       if (branch.Symbol is Power) {
         // HL evaluators handle power strangely (exponent is rounded to an integer)
-        // here we only support the case when the exponent is a constant integer and 
+        // here we only support the case when the exponent is a constant integer 
         var exponent = branch.GetSubtree(1) as ConstantTreeNode;
         if (exponent != null && Math.Truncate(exponent.Value) == exponent.Value) {
           var newPower = (ISymbolicExpressionTreeNode)branch.Clone();
+          var f = (ISymbolicExpressionTreeNode)newPower.GetSubtree(0).Clone();
           var newExponent = (ConstantTreeNode)newPower.GetSubtree(1);
           newExponent.Value -= 1;
-          return Product(CreateConstant(exponent.Value), newPower);
+          return Product(Product(CreateConstant(exponent.Value), newPower), Derive(f, variableName));
         } else throw new NotSupportedException("Cannot derive non-integer powers");
       }