function [Output] = modell(tspan,Parameter)
%% calls the ode45 solver 
% 
%% global variables
global par;
global t_out;
global init_conc;
% init_conc=Initial_Concentration_vector;

par = Parameter;
%% start the simulation
% [t_out,Output] = ode113(@pathwayIGEM,tspan,init_conc);
[t_out,Output] = ode45(@pathwayIGEM,tspan,init_conc);
end 

