added example code

added better default range
fixed BIGDOUBLE to be closer to max double (used for default best fitness)

de.h

@@ -50,6 +50,7 @@ namespace DE
 
 		static const double DEFAULTSCALE;
 		static const double DEFAULTCROSSOVER;
+		static const double DEFAULTRANGE;
 		static const double BIGDOUBLE;
 
 

de.inl

@@ -17,7 +17,10 @@ template <unsigned int DIM, unsigned int POP>
 const double DE::Engine<DIM,POP>::DEFAULTCROSSOVER = 1.0;
 
 template <unsigned int DIM, unsigned int POP>
-const double DE::Engine<DIM,POP>::BIGDOUBLE = 1.0e30;
+const double DE::Engine<DIM,POP>::DEFAULTRANGE= 1000000.0;
+
+template <unsigned int DIM, unsigned int POP>
+const double DE::Engine<DIM,POP>::BIGDOUBLE = 9.0e300; // close to max double
 
 template <unsigned int DIM, unsigned int POP>
 inline DE::Engine<DIM,POP>::Engine()
@@ -27,7 +30,7 @@ inline DE::Engine<DIM,POP>::Engine()
 
 	for ( unsigned int i=0;i<DIM;i++ )
 	{
-		this->minimum[i] = -BIGDOUBLE;
+		this->minimum[i] = -DEFAULTRANGE;
 		this->maximum[i] = -(this->minimum[i]);
 	}
 

example.cpp

@@ -0,0 +1,43 @@
+#include <cstdio>
+
+#include "de.h"
+
+// just a helper function used in calculating the polynomails
+double Polynomial(double x, double a, double b, double c, double d)
+{
+	return a*(x*x*x) + b*(x*x) + c*x + d;
+}
+
+// the function we're searching for
+double TargetFunction(double input)
+{
+	return Polynomial(input,17.0,321.0,-2.0,324.0);
+}
+
+// our DE implementation
+class PolySearch: public DE::Engine<4>
+{
+	public:
+		double CalculateError(const double testcase[4], bool& stop)
+		{
+			double error = 0.0;
+			for ( int i=-100;i<=100;i++ )
+			{
+				double test   = Polynomial((double)i,testcase[0],testcase[1],testcase[2],testcase[3]);
+				double actual = TargetFunction((double)i);
+				error += (test-actual)*(test-actual);
+			}
+			if ( error < 0.00000000000001 )
+			{
+				stop = true;
+			}
+		}
+};
+
+// main program
+int main()
+{
+	PolySearch de;
+	de.Solve();
+	return 0;
+}