Maximum recursion limit of 500 reached.

I am trying to plot with this code below but keep getting a Maximum recursion limit of 500 reached error.

function yp = nonlinear (t,y)

e = .2;

yp(1) = y(2);

yp(2) = (-y(1)-e*y(1)^3);

tspan = [0 20];

y0 = [0;0];

[t,y] = ode45('nonlinear', tspan, y0);

plot (t,y(:,1))

grid

xlabel ('time')

ylabel ('u')

title ('u vs t')

Answer 1

[Cris LaPierre]

You have given your plotting function and your odefunc the same name. This is causing ode45 to call your function recursively (call itself).

Change the name of either give your odefunc or you plotting function.

[Anna Taylor]

**ok so i changed the name of the plotting function

function yp = nonlinear (t,y)

e = .2;

yp(1) = y(2);

yp(2) = (-y(1)-e*y(1)^3);

tspan = [0 20];

y0 = [0;0];

[t,y] = ode45('non', tspan, y0);

plot (t,y(:,1))

grid

xlabel ('time')

ylabel ('u')

title ('u vs t')

**But now i'm getting new errors:

Error using feval

Unrecognized function or variable 'non'.

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);

Error in nonlinear (line 7)

[t,y] = ode45('non', tspan, y0);

**I'm really sorry. I've never used MATLAB before so I'm just lost in what I'm doing.

[Cris LaPierre]

I've never used MATLAB before so I'm just lost in what I'm doing.

I suggest going through MATLAB Onramp. It doesn't cover odes, but it will at least give you the basics, which you will need for a foundation to build on.

Now the error is that you have not defined an ode to solve, at least not the way MATLAB is expecting. See this example on the ode45 documentation page.

I think you want something like this.

tspan = [0 20];
y0 = [0;0];
[t,y] = ode45(@non, tspan, y0);
plot (t,y(:,1))
grid
xlabel ('time')
ylabel ('u')
title ('u vs t')

function yp = non(t,y)
yp = zeros(2,1);
e = .2;
yp(1) = y(2);
yp(2) = (-y(1)-e*y(1)^3);
end