(* Generated by JWS Online *)

(* This is an experimental feature of JWS Online. Please report any mistakes.*)

(* Note that the following notable SBML entities or features are not supported in notebook outputyet: *)
    (* Events *)
    (* Constraints *)
    (* Units and UnitDefinitions *)
    (* AlgebraicRules *)
    (* conversionFactors *)

variables = {
R[t], X[t]
};

initialValues = {
R[0] == 1, X[0] == 0.0
};

rates = {
r1, r2, r3, r4
};

rateEquations = {
r1 -> env*k1*S, r2 -> env*k2*R[t]*X[t], r3 -> env*k3*S, r4 -> env*k4*X[t]
};

parameters = {
k1 -> 2.0, k2 -> 2.0, k3 -> 1.0, k4 -> 1.0, tau -> 4.0, env -> 1.0
};

assignments = {
S -> Floor[t/tau]
};

events = {

};

speciesAnnotations = {

};

reactionAnnotations = {

};

units = {
{"time" -> "", "metabolite" -> "", "extent" -> ""}
};

(* Time evolution *)
odes = {
R'[t] == 1.0*r1 -1.0*r2, X'[t] == 1.0*r3 -1.0*r4
};
timeCourse = NDSolve[Join[odes, initialValues]//.rateEquations//.assignments//.parameters, variables, {t, 0, 100}];

(* Steady-state solution initialized with result of time evolution *)
findRootEquations = odes /.D[_[t],t]->0;
findRootVariables = Partition[Flatten[{#, #/.timeCourse/.t->100} &/@variables],2];
steadyStateVariables = FindRoot[findRootEquations//.rateEquations//.assignments//.parameters, findRootVariables, MaxIterations->100]
fluxes = #//.assignments//.parameters/.steadyStateVariables&/@rateEquations

(* Plot the time evolution of the variables *)
plotTable=Table[Plot[variables[[i]]/.parameters/.timeCourse,{t,0,100},PlotLegends->variables[[i]],PlotRange->Full],{i,Length[variables]}]