Delayed evalution of fmin and fmax.

Author: jkalias

src/Numerics/RootFinding/RobustNewtonRaphson.cs

@@ -74,16 +74,16 @@ public static bool TryFindRoot(Func<double, double> f, Func<double, double> df,
                 throw new ArgumentOutOfRangeException(nameof(accuracy), "Must be greater than zero.");
             }
 
-            double fmin = f(lowerBound);
-            double fmax = f(upperBound);
-
             root = lowerBound + 0.5 * (upperBound - lowerBound);
             double fx = f(root);
             if (Math.Abs(fx) < accuracy)
             {
                 return true;
             }
 
+            double fmin = f(lowerBound);
+            double fmax = f(upperBound);
+
             if (Math.Abs(fmin) < accuracy)
             {
                 root = lowerBound;