Changeset 17300

Timestamp:

10/03/19 10:27:12 (5 years ago)

Author:

chaider

Message:

#2971: Fixed calculation of cubic roots (negative numbers)

File:

• branches/2971_named_intervals/HeuristicLab.Problems.DataAnalysis/3.4/Implementation/Interval/Interval.cs (modified) (2 diffs)

branches/2971_named_intervals/HeuristicLab.Problems.DataAnalysis/3.4/Implementation/Interval/Interval.cs

@@ -38 +38 @@
 
     public Interval(double lowerBound, double upperBound) {
-      //TODO Handle floating point issues where lowerbound is bigger than upperbound in the nth decimal place 
+      //TODO Handle floating point issues where lowerbound is bigger than upperbound in the nth decimal place
       if (lowerBound > upperBound)
         throw new ArgumentException("lowerBound must be smaller than or equal to upperBound.");
@@ -264 +264 @@
 
     public static Interval CubicRoot(Interval a) {
-      if (a.LowerBound < 0) return new Interval(double.NaN, double.NaN);
-      return new Interval(Math.Pow(a.LowerBound, 1.0/3), Math.Pow(a.UpperBound, 1.0/3));
+      var lower = (a.LowerBound < 0) ? -Math.Pow(-a.LowerBound, 1d / 3d) : Math.Pow(a.LowerBound, 1d / 3d);
+      var upper = (a.UpperBound < 0) ? -Math.Pow(-a.UpperBound, 1d / 3d) : Math.Pow(a.UpperBound, 1d / 3d);
+
+      return new Interval(lower, upper);
     }
     #endregion