It takes too long to run the program and in the end I get an error, could you tell me what the error is?

function f=funcionrr(x)

xini=[0 4*pi];

t=[0 2*pi];

options=odeset('RelTol',1e-13,'AbsTol',1e-13);

[ts,xs]=ode45(@campo_pendulo,t,xini,options);

f=xs(end,1);

end

function px = campo_pendulo(t,x)

px(1)= x(2);

px(2)=sin(x(1))+0.5*sin(t);

px=px';

% Definir los límites de la búsqueda

x_min = 0;

x_max = 2*pi;

x = (x_min + x_max)/2;

while abs(px) > 1e-6

if px > 0

x_max = x;

else

x_min = x;

end

x = (x_min + x_max)/2;

end

end

Answer 1

[Torsten]

You can't change the input for x in function "campo_pendulo".

So you can delete this part of your code because it doesn't influence the results:

% Definir los límites de la búsqueda
x_min = 0;
x_max = 2*pi;
x = (x_min + x_max)/2;
while abs(px) > 1e-6
    if px > 0
        x_max = x;
    else
        x_min = x;
    end
    x = (x_min + x_max)/2;
end

Further it doesn't make sense to use a while loop here because px is not changed within the loop. So once abs(px) > 1e-6, you will enter the loop, but never exit.

f = funcionrr()

f = 82.5899

function f=funcionrr()
xini=[0 4*pi];
t=[0 2*pi];

options=odeset('RelTol',1e-13,'AbsTol',1e-13);

[ts,xs]=ode45(@campo_pendulo,t,xini,options);

f=xs(end,1);
plot(ts,xs)
end
function px = campo_pendulo(t,x)
px(1)= x(2);
px(2)=sin(x(1))+0.5*sin(t);
px=px';

end

[Freddy]

The work I have to do is that according to that function I must add the dichotomous search, that's why I used the while loop, or how could I propose it?

[Torsten]

I don't understand what you want to achieve in this part of your code:

% Definir los límites de la búsqueda
x_min = 0;
x_max = 2*pi;
x = (x_min + x_max)/2;
while abs(px) > 1e-6
    if px > 0
        x_max = x;
    else
        x_min = x;
    end
    x = (x_min + x_max)/2;
end