BYOM function simplefun.m (the model as explicit equations)

Syntax: Xout = simplefun(t,X0,par,c)

This function calculates the output of the model system. It is linked to the script files byom_bioconc_extra.m and byom_bioconc_start.m. As input, it gets:

Time t is handed over as a vector, and scenario name c as single number, by call_deri.m (you do not have to use them in this function). Output Xout (as matrix) provides the output for each state at each t.



function Xout = simplefun(t,X0,par,c)
global glo   % allow for global parameters in structure glo (handy for switches)

Unpack initial states

The state variables enter this function in the vector _X_0.

Y = X0(1); % state 1 is the response at t=0

Unpack parameters

The parameters enter this function in the structure par. The names in the structure are the same as those defined in the byom script file. The 1 between parentheses is needed as each parameter has 5 associated values.

ECx  = par.ECx(1);  % concentration for x% effect (x in glo.x_EC)
Y0   = par.Y0(1);   % response in control
beta = par.beta(1); % slope factor of the dose response

Calculate the model output

This is the actual model, specified as explicit function(s):

x = glo.x_EC;
y = Y0 ./ (1+(x/(100-x))*(t/ECx).^beta);

Xout = [y]; % combine them into a matrix