using System;

namespace Science.Mathematics.VectorCalculus
{
    public class DirectionalDerivative
    {
        private Function.ToLastType<double[], double> func;
        public DirectionalDerivative(Function.ToLastType<double[],double> f, 
            Vector direction, double[] at)
        {
            func = f;
            v = direction;
            x = at;
        }
        private Vector v;
        public Vector Direction
        {
            get { return v; }
            set { v = value; }
        }
        private double[] x;
        public double[] At
        {
            get { return x; }
            set { x = value; }
        }
        public void Compute()
        {
            Gradient obj = new Gradient(func, x);
            obj.Compute();
            Vector df = new Vector(obj.Result);
            res = df * v;
        }
        private double res;
        public double Result
        {
            get { return res; }
        }
    }
}