public void ODEExplicitRungeKutta45()
{
//Arenstorf orbit
//The Arenstorf orbits are closed trajectories of the restricted three-body problem.
//Two bodies of masses m and (1-m) moving in a circular rotation, and a third body of
//negligible mass moving in the same plane (such as a satellite-earth-moon system.)
//using DotNumerics.ODE
OdeFunction fun = new OdeFunction(ArenstorfOrbit);
OdeExplicitRungeKutta45 RK45 = new OdeExplicitRungeKutta45(fun, 4);
RK45.RelTol = 1.0E-7;
RK45.AbsTol = 1.0E-7;
double x0 = 0;
double[] y0 = new double[4];
y0[0] = 0.994E0;
y0[1] = 0.0E0;
y0[2] = 0.0E0;
y0[3] = -2.00158510637908252240537862224E0;
RK45.SetInitialValues(x0, y0);
double[,] y;
double[] x = new double[10];
for (int i = 0; i < 10; i++)
{
x[i] = 2 * i;
}
y = RK45.Solve(y0, x);
for (int i = 0; i < 10; i++)
{
ObjectDumper.Write("X = " + x[i].ToString() + " Y1 = " + y[i, 1].ToString() + " Y2 = " + y[i, 2].ToString());
}
//private double[] ArenstorfOrbit(double t, double[] y)
//{
// double[] ydot = new double[4];
// double amu = 0; double amup = 0; double r1 = 0; double r2 = 0;
// double a = 0.012277471E0;
// double b = 1 - a;
// amu = a;
// amup = b;
// ydot[0] = y[2];
// ydot[1] = y[3];
// r1 = Math.Pow(y[0] + amu, 2) + Math.Pow(y[1], 2);
// r1 *= Math.Sqrt(r1);
// r2 = Math.Pow(y[0] - amup, 2) + Math.Pow(y[1], 2);
// r2 *= Math.Sqrt(r2);
// ydot[2] = y[0] + 2 * y[3] - amup * (y[0] + amu) / r1 - amu * (y[0] - amup) / r2;
// ydot[3] = y[1] - 2 * y[2] - amup * y[1] / r1 - amu * y[1] / r2;
// return ydot;
//}
}
public double[,] Ode(double[] y0, double[] x)
{
OdeExplicitRungeKutta45 RK45 = new OdeExplicitRungeKutta45(Simulate, 12)
{
RelTol = 0.000001,
AbsTol = 0.000001
};
return(RK45.Solve(y0, x));
}
