using System;

namespace Science.Mathematics.VectorCalculus
{
    public class Curl
    {
        private Function.ToLastType<double[], double[]> func;
        private Vector res = new Vector(3);
        private double[] at1;
        public Curl(Function.ToLastType<double[], double[]> f,
            double[] x)
        {
            if (x.Length != 3) try { throw new Science.Error(); }
                catch (Science.Error e)
                {
                    e.Write("Bad dimension. Only 3 dimension is considered.");
                }; 
            func = f;
            at1 = x;
        }
        public double[] At
        {
            set { at1 = value; } 
        }
        private int cp;
        public void Compute()
        {
            res[0] = 0.0;
            res[1] = 0.0;
            res[2] = 0.0;
            Function.ToLastType<double[], double> part
                = new Function.ToLastType<double[], double>(comp);
            PartialDerivative obj;

            cp = 2;
            obj = new PartialDerivative(part, at1);
            obj.WithRespectTo = 1;
            obj.Compute();
            res[0] += obj.Result;

            cp = 1;
            obj = new PartialDerivative(part, at1);
            obj.WithRespectTo = 2;
            obj.Compute();
            res[0] -= obj.Result;

            cp = 0;
            obj = new PartialDerivative(part, at1);
            obj.WithRespectTo = 2;
            obj.Compute();
            res[1] += obj.Result;

            cp = 2;
            obj = new PartialDerivative(part, at1);
            obj.WithRespectTo = 0;
            obj.Compute();
            res[1] -= obj.Result;

            cp = 1;
            obj = new PartialDerivative(part, at1);
            obj.WithRespectTo = 0;
            obj.Compute();
            res[2] += obj.Result;

            cp = 0;
            obj = new PartialDerivative(part, at1);
            obj.WithRespectTo = 1;
            obj.Compute();
            res[2] -= obj.Result;
        }       
        private double comp(double[] x)
        {
            return func(x)[cp];
        }
        public Vector Result
        {
            get { return res; }
        }
    }
}