function yprime=ode3(x,y)

% ode3(x,y) contains the rhs of an 3D ode system
% rhs ODE solver

yprime=zeros(3,1);

% forced harmonic oscillator
%yprime=[y(2); -y(1)];

% forced damped harmonic oscillator
%beta=0.1;
%yprime=[y(2); -y(1)-beta*y(2)];

% forced van der Pol
%yprime=[y(2);(1. -y(1)^2)*y(2)-y(1)];

% Lotka-Volterra
%a1=0.08; a2=1;b1=0.00001;b2=0.002;
% yprime=[y(1)*(-a1+b1*y(2));(a2 -b2*y(1))*y(2)];

% Lorenz model
sigma=10. ; b=8/3; r=28;
yprime=[sigma*(y(2)-y(1));(r-y(3))*y(1)-y(2);y(1)*y(2)-b*y(3)];

% Grenzzyklus
% yprime=[y(1)-y(2)-y(1)*(y(1)*y(1)+y(2)*y(2));y(1)+y(2)-y(2)*(y(1)*y(1)+y(2)*y(2));y(3)];