4th order RUNGE KUTTA METHOD for more that 3 coupled equations in MATLAB -

can please tell me how implement 4th order runge kutta method more 3 coupled equations in matlab.

regards

faiz

if have version vector valued ode 1 dimension, have dimensions. (syntax may have corrected errors, works under scilab, close, not idential matlab)

function [t, y] = rk4(odefunc, y0, t0, tf, n)     t = tf-t0;     h=t/n;     time=t0;     state=y0;     t = zeros(n+1);     y = zeros(n+1,length(y0));     t(1) = t0;     y(1,:) = y0;      i=2:n+1         k1 = odefunc(time        , state           );         k2 = odefunc(time + 0.5*h, state + 0.5*h*k1);         k3 = odefunc(time + 0.5*h, state + 0.5*h*k2);         k4 = odefunc(time +     h, state +     h*k3);         state = state + (h/6)*(k1+2*k2+2*k3+k4);         time = time + h;         t(i) = time;         y(i,:) = state;     end endfunction  function doty = lorenz(t, y, params)     a=params(1); b=params(2); c=params(3);     doty = [ * ( y(2) - y(1) )     -b * y(1) + y(1) * y(3)     -c * y(1) - b * y(3) ]' endfunction  function doty=odefunc(t,y)     doty = lorenz(t,y,[0.5, 0.66, 1.4]) endfunction  [t,y] = rk4(odefunc, [-1.2 0.2 0.8], 0, 10, 400)