"Henry" wrote in message <email@example.com>... > I modified the code to: > > tspan = linspace(1, 2,100); > y = 0.0001*ones(1,200); > [T,sols] = ode45(@yprime, tspan,y); > and > dyds = [dyds1' ; dyds2']; > > and it now runs, thanks. > > But I have this question: My odes are time-independent, function of "s" which is a distance, but since the ode45 will not work without a tspan, I came up with an arbitrary tspan. It looks as if ode45 interprets that "s" is a time? I'm confused as to how interpret the result of the routine which has dimensions of 100x200. I was expecting 1 x 200, i.e. independent of time. > thanks
Just interpret your results for y(1) and y(2) as functions of distance, not of time. So "tspan" in your case is a distance vector, not a time vector.