Error: maximum recursion limit of 500 reached while trying to plot models.

I am trying to plot a SIER model. The first few time I ran my script I was able to have a figure created with the four models (SIER) in figure 1.

However, now I am getting this error message.

Error in odearguments (line 90)

f0 = feval(ode,t0,y0,args{:}); % ODE15I sets args{1} to yp0.

Caused by:

Maximum recursion limit of 500 reached.

Here is my script that I am running:

S_i = 5;

I_i = 10^-6;

R_i = 0;

E_i = 5;

initial_values = [S_i,I_i,R_i,E_i];

% Use odr45 function to solve differential equations

figure(1)

[t,x] = ode45('sir_2', [0 80], initial_values,[]);

% Plot models

plot(t,x);

hold on

% Create labels

legend("s","i","r","e");

title("SIR model");

ylabel("Population");

xlabel("Time");

[Walter Roberson]

Did you name that script sir_2? If not then what does sir_2 contain?

[Joshua Yang]

This is what sir_2 contain. I named the script sir_model

function [d, initial_values] = sir_2(t,x)

% S - Susceptibles - People who could potentially have the disease.
% I - Infectives -  Have disease and could infect other.
% R - Removed - People who had recovered or died.
% E - Exposed

%% Assumptions
% Total population is constant.
% Infectives receiver/die rate is constant.
S = x(1);
I =x(2);
R = x(3);
E = x(4);

d = [0;0;0;0];
% S0 >= a/r
r = 0.50;
a = 0.30;
%% Define differential equations
%ds/dt = -rIS
dS = -r * S * I;
%dI/dt = rIS - aI
dI = r*I*S - a*I;
%dR/dt = aI
dR = r* I;
%dE/dt = -rIS - aE
dE = r*I*S - a*E;

d(1) = dS;
d(2) = dI;
d(3) = dR;
d(4) = dE;

[Walter Roberson]

The code works without difficulty for me.

What shows up for

which -all plot

[Joshua Yang]

Thank you for your help, the error message went away for me.