c# - solving complexed ODE set

Question

Introduction Some sets od ODE can\'t be solved analytically. In this case there are plenty of well-know methods, especially in typical scientific software l

Answer 1

You should be able to use

var sol = Ode.RK547M(0, new Vector(5.0, 1.0),
    (t, u) => {
        double x=u[0], y=u[1];
        double a=x*2+7, b=y*x+3;
        double c = additional_solve(b, x);
        return new Vector(
            x - x*y + a + c,
            -y +x*y + b
        );
     });

as the long form of a lambda delegate definition, that is, using that x => x*x is short for x => { return x*x; } which is short for delegate(x) { return x*x; } and so on.