#Biological reactor with no inflow or outflow
class Batch:
    #Define values that stay constant during the simulation.
    data mu_max, Ks, Yxs: Float param
    #Define values that change during the simulation.
    data mu, X, S: Float

    #Initialize the simulation.
    func initialize(this):
        #Specify options for the simulation algorithm.
        solution_parameters(duration=20, reporting_interval=0.1)
        #Give values to the parameters
        mu_max = 0.32 #[1/h] max growth speed
        Ks     = 0.01 #[g/l] at this lactate concentration growth speed is 0.5*mu_max
        Yxs    = 0.5  #[g/g] one g lactate gives this much biomass
        #Give initial values to the state variables.
        X      = 0.1  #[g/l] initial biomass concentration
        S      = 20   #[g/l] initial sugar concentration

    #compute dynamic behavior - the system's 'equations'
    func dynamic(this):
        mu = mu_max * S/(S+Ks) #growth speed (of biomass) [1/h]
        $X = mu*X              #change of biomass concentration [g/l/h]
        $S = -1/Yxs*mu*X       #change of sugar concentration [g/l/h]

    #show results
    func final(this):
        graph(mu, X, S, title="Batch Reactor");
        #For the test scripts
        print("final-values:", X, S, time)


compile Batch