using System;

using System.Windows.Forms;

using DotNumerics.ODE;

namespace DotNumericsDemo.DifferentialEquations

{

    public partial class ExplicitRungeKutta : Form

    {

        private OdeExplicitRungeKutta45 odeRK = new OdeExplicitRungeKutta45();

        private void Solve()

        {

            OdeFunction fun = new OdeFunction(ODEs);

            double[] y0 = new double[3];

            y0[0] = 0;

            y0[1] = 1;

            y0[2] = 1;

            this.odeRK.InitializeODEs(fun, 3);

            double[,] sol = odeRK.Solve(y0, 0, 0.03, 15);

        }

        //Euler equations of a rigid body without external forces.

        //y0' = y1 * y2 ,                 y0(0)=0       

        //y1' = -y0 * y2,                 y1(0)=1 

        //y2' = -0.51 * y0 * y1,          y2(0)=1     

        double[] yprime = new double[3];

        private double[] ODEs(double t, double[] y)

        {

            yprime[0] = y[1] * y[2];

            yprime[1] = -y[0] * y[2];

            yprime[2] = -0.51 * y[0] * y[1];

            return this.yprime;

        }

    }

}