*Passing a Method into a Class

Question

Hi all, I'm coding a small class that maximizes a given function F and returns the coordinates. For example in maximizing the 1-dimensional fitness function below I currently have:

using System;

public static class Program
{
    public static double F(double x)
    {
        // for example
        return Math.Exp(0.4 * Math.Pow(x - 0.4, 2) - 0.08 * Math.Pow(x, 4));
    }

    static void Main(string[] args)
    {

    Metaheutistic Solve = new Metaheutistic;

    Solve.Maximize(Mu, Lambda, Theta);

    }
}

The method "Maximize" in the class Metaheutistic contains the algorithm that does all the work. My problem is this algorithm is in a class that does not know what the fitness function looks like.

I'm new to C# and if I've gone on a bender here I'm open to doing it all over again to get it right. I do however need to keep the Solver class separate from the fitness function.

Many thanks. *I'm not sure "Passing" is the correct term I'm looking for

Answer 1

You can indeed pass methods into functions using a delegate, for example:

public delegate double FitnessDelegate(double x);

declares a delegate to a function which takes a double parameter and returns a double. You can then create a reference to the real function, and pass this to the Solve method to be called.

public static class Program
{
    public static double F(double x)
    {
        // for example
        return Math.Exp(0.4 * Math.Pow(x - 0.4, 2) - 0.08 * Math.Pow(x, 4));
    }

    static void Main(string[] args)
    {
    FitnessDelegate fitness = new FitnessDelegate(F);
    Metaheutistic Solve = new Metaheutistic;

    Solve.Maximize(fitness);

    }
}

within the Solve method you may call this delegate as you would a method and it will in fact be executing the actual method:

class Metaheutistic 
{
  public void Maximise(FitnessDelegate fitness)
  {
    double result = fitness(1.23);
  }
}