ffs_ode_mod.m

 function dydt = ffs_ode_mod(t, y, params)
%ffs_ode_mod describes odes for ffs with varying input
%
%   t: the current time
%   y: set of current reactant values, of the form [A B]
%   params: set of parameters containing-
%            k1, k2, k3, K3, k4, I1, I2, perturb_time
%
%   dydt: set of calculated derivatives of the form [dA/dt dB/dt]

A = y(1);
B = y(2);

I = params(6);

if(t > params(8))
    I = params(7);
end

dA = params(1)*I*(1-A)-(params(2)*A*B);
dB = params(3)*I*((1-B)/(params(4)+1-B))-(params(5)*B);

dydt = [dA; dB];