getODEderivatives()

Get derivatives of an ODE syste,

Syntax: dydt=getODEderivatives(t,y,odehandler)

This function is used to get the time course derivatives
evaluated to solve an ode system using Matlab solvers
(ode45,ode23,ode23s and so on).

Example:

Want to solve the system and plot the solution as well as how the derivatives change:
dudt=w;
dwdt=-u;

u(0)=0;
w(0)=1;

odehandler=@(t,y) [y(2);-y(1)];
[t,y]=ode45(odehandler,[0 4*pi],[0 1]);
u=y(:,1);
w=y(:,2);

(select the code below and press F9 to run it).

dydt=getODEderivatives(t,y,odehandler);
dudt=dydt(:,1);
dwdt=dydt(:,2);

%Check that dudt=w;
sum(dudt==w)==length(t)
plot(t,dudt,'r--',t,w,'g-.')
legend('dudt','w')

%Check that dwdt=-u;
sum(dwdt==-u)==length(t)
figure
plot(t,dwdt,'r--',t,-u,'g-.')
legend('dwdt','-u')