For the following code, I am getting an error and I am unable to figure out why. Any help would be handy.
%MATLAB SYMBOL DESCRIPTION IC Units
%x(1) X Cell Concentration 0.5 kmol/m3
%x(2) S Substrate Concentration 0.38 kmol/m3
%x(3) P Product Concentration 0 kmol/m3
%x(4) G Glycerol Concentration 0 kmol/m3
%x(5) V Volume 0 m3
ic = [0.5; 0.38; 0; 0; 0]; %MATLAB PARAMETER DESCRIPTION Value UNITS
%mumax mu_{max} Maximum Growth Rate 0.2 1/hour
%Ks K_s Monod Constant 2 kg/m3
%Yxs Y_{X/S} Cell Yield 0.58 kg/kg
%Ypx Y_{P/X} Product Yield 0.2 kg/kg
%Yxo Y_{X/O} Glycerol Yield
%Sf S_f Feed Substrate Concentration 0.37 kmol/m3
%Kp K_p Product Inhibition 97.9 kg/m3
mumax = 0.20;Ks = 2;Yxs = 0.58;Ypx = 0.2; Yxo = 2.46;Sf = 0.37;Kp = 97.9; mu = @(S,P) (mumax*S./(Ks + S))*(1 - (P/Kp))^0.5; % Monod Equation
rg = @(X,S,P) mu(S,P)*X; % Rate of cell growth
rp = @(X,S,P) Ypx*rg(X,S,P); % Rate of ethanol formation
rpg = @(X,S,P,G) Yxo*rg(X,S,P); % Rate of glycerol formation
F = @(t) 2; dXV = @(t, x) x(5) *rg(x(1),x(2),x(3));dPV = @(t, x) x(5) *rp(x(1),x(2),x(3));dSV = @(t, x) F(t)*Sf - x(5)*rg(x(1),x(2),x(3),x(4))/Yxs;dGV = @(t, x) x(5) *rpg(x(1),x(2),x(3));dV = @(t, x) F(t); dX = @(t, x) (dXV(t,x) - x(1)*dV(t,x))/x(5);dS = @(t, x, s) (dSV(t,x) - x(2)*dV(t,x))/x(5);dP = @(t, x, p) (dPV(t,x) - x(3)*dV(t,x))/x(5);dG = @(t, x, g) (dGV(t,x) - x(4)*dV(t,x))/x(5); f = @(t,x) [dX(t,x); dS(t,x,s); dP(t,x,p); dG(t,x,g); dV(t,x)]; tspan = [0 100];[t,x] = ode45(f,tspan,ic); subplot(2,2,1);plot(t,x(:,1));xlabel('Time (hr)');ylabel('X (kmol/m3)');title('Cell Concentration'); subplot(2,2,2);plot(t,x,s(:,3));xlabel('Time (hr)');ylabel('P (kmol/m3 )');title('Product Concentration'); subplot(2,2,3);plot(t,x,p(:,2));xlabel('Time (hr)');ylabel('S (kmol/m3)');title('Substrate Concentration'); subplot(2,2,4);plot(t,x,g(:,4));xlabel('Time (hr)');ylabel('V (m3)');title('Volume');subplot(2,2,5);plot(t,x,g,p(:,5));xlabel('Time (hr)');ylabel('Glycerol Concentration (kmol/m3)');title('Glycerol');The error is:
Undefined function or variable 's'.
Error in @(t,x)[dX(t,x);dS(t,x,s);dP(t,x,p);dG(t,x,g);dV(t,x)]
Error in odearguments (line 90)
f0 = feval(ode,t0,y0,args{:}); % ODE15I sets args{1} to yp0.
Error in ode45 (line 115)
odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options,
varargin);
Best Answer