Changeset 17827 for branches/3073_IA_constraint_splitting/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Converters

Timestamp:

01/31/21 08:08:32 (4 years ago)

Author:

gkronber

Message:

#3073 merged r17811:17826 from trunk to branch

Location:

branches/3073_IA_constraint_splitting/HeuristicLab.Problems.DataAnalysis.Symbolic

Files:

• . (modified) (1 prop)
• 3.4/Converters/TreeSimplifier.cs (modified) (3 diffs)
• 3.4/Converters/TreeToAutoDiffTermConverter.cs (modified) (2 diffs)

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

@@ -934 +934 @@
         var constBValue = Math.Round(constB.Value);
         if (constBValue == 1.0) {
+          // root(a, 1) => a
           return a;
         } else if (constBValue == 0.0) {
-          return MakeConstant(1.0);
+          // root(a, 0) is not defined 
+          //return MakeConstant(1.0);
+          return MakeConstant(double.NaN);
         } else if (constBValue == -1.0) {
+          // root(a, -1) => a^(-1/1) => 1/a
           return MakeFraction(MakeConstant(1.0), a);
         } else if (constBValue < 0) {
+          // root(a, -b) => a^(-1/b) => (1/a)^(1/b) => root(1, b) / root(a, b) => 1 / root(a, b)
           var rootNode = rootSymbol.CreateTreeNode();
           rootNode.AddSubtree(a);
@@ -988 +993 @@
         double exponent = Math.Round(constB.Value);
         if (exponent == 0.0) {
+          // a^0 => 1
           return MakeConstant(1.0);
         } else if (exponent == 1.0) {
+          // a^1 => a
           return a;
         } else if (exponent == -1.0) {
+          // a^-1 => 1/a
           return MakeFraction(MakeConstant(1.0), a);
         } else if (exponent < 0) {
+          // a^-b => (1/a)^b => 1/(a^b)
           var powNode = powSymbol.CreateTreeNode();
           powNode.AddSubtree(a);
@@ -1019 +1028 @@
         return MakeConstant(((ConstantTreeNode)a).Value / ((ConstantTreeNode)b).Value);
       } else if ((IsConstant(a) && ((ConstantTreeNode)a).Value != 1.0)) {
+        // a / x => (a * 1/a) / (x * 1/a) => 1 / (x * 1/a)
         return MakeFraction(MakeConstant(1.0), MakeProduct(b, Invert(a)));
       } else if (IsVariableBase(a) && IsConstant(b)) {

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

@@ -258 +258 @@
       if (node.Symbol is CubeRoot) {
         return cbrt(ConvertToAutoDiff(node.GetSubtree(0)));
+      }
+      if (node.Symbol is Power) {
+        var powerNode = node.GetSubtree(1) as ConstantTreeNode;
+        if (powerNode == null)
+          throw new NotSupportedException("Only integer powers are allowed in parameter optimization. Try to use exp() and log() instead of the power symbol.");
+        var intPower = Math.Truncate(powerNode.Value);
+        if (intPower != powerNode.Value)
+          throw new NotSupportedException("Only integer powers are allowed in parameter optimization. Try to use exp() and log() instead of the power symbol.");
+        return AutoDiff.TermBuilder.Power(ConvertToAutoDiff(node.GetSubtree(0)), intPower);
       }
       if (node.Symbol is Sine) {
@@ -340 +349 @@
           !(n.Symbol is AnalyticQuotient) &&
           !(n.Symbol is Cube) &&
-          !(n.Symbol is CubeRoot)
+          !(n.Symbol is CubeRoot) &&
+          !(n.Symbol is Power)
         select n).Any();
       return !containsUnknownSymbol;