Changeset 18130

Timestamp:

12/15/21 11:36:06 (3 years ago)

Author:

gkronber

Message:

#3140 fixed a problem in the DerivativeCalculator for powers with constant exponents

File:

• branches/3140_NumberSymbol/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Converters/DerivativeCalculator.cs (modified) (1 diff)

branches/3140_NumberSymbol/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Converters/DerivativeCalculator.cs

@@ -156 +156 @@
           var newPower = (ISymbolicExpressionTreeNode)branch.Clone();
           var f = (ISymbolicExpressionTreeNode)newPower.GetSubtree(0).Clone();
-          var newExponent = (INumericTreeNode)newPower.GetSubtree(1);
-          newExponent.Value -= 1;
+          var newExponent = (INumericTreeNode)numberSy.CreateTreeNode();
+          newExponent.Value = ((INumericTreeNode)newPower.GetSubtree(1)).Value - 1;
           return Product(Product(CreateNumber(exponent.Value), newPower), Derive(f, variableName));
         } else throw new NotSupportedException("Cannot derive non-integer powers");