Issues with my Bifurcation Diagram

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Emily Tabb 2021-5-26

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/840080-issues-with-my-bifurcation-diagram

评论： Star Strider 2021-5-26

My code is completing but will not graph any data and i'm not sure why, I need to plot k againct c as my parameters

Can anyone else see the problem

thankyou

figure;

ax(1);

hold on

xlabel ('k');

ylabel ('C');

xlim([-2 2]);

ylim([0 40]);

dt = 0.01;

N = 10000;

for k=-2:0.1:10

c = zeros(N,1);

c(1)= 23;

t(1) = 0;

for i=1:N

t(i+1) = t(i) + dt;

c(i+1) = c(i) + dt*((1/10)*((c(i)-23)*(25-c(i))*(c(i)-29))-k);

end

plot(ax(1),k,c,'color','blue','marker','.');

end

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Torsten 2021-5-26

编辑：Torsten 2021-5-26

Maybe somebody can help if you report the complete error message.

You will have to plot c against t, not c against k.

Emily Tabb 2021-5-26

i need to plot c against k, as it is in the equation and is the parameter that i am changing, will it be better if i just remove t?

Error was probably the wrong word, the code completes but when the figure presents itself there is nothing on it, there is no graph on it at all

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Answer 1

Star Strider 2021-5-26

0
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/840080-issues-with-my-bifurcation-diagram#answer_709335

在 MATLAB Online 中打开

One problem is that ‘ax(1)’ does not have anything assigned to it, at least in the posted code. Fixing that makes the axes magickally appear!

Beyond that, the code takes a while to run, so I changed ‘N’ to a value that does not time-out the online Run feature 55 second limit. It does not look like a bifurcation diagram, but at least now it plots.

figure;

ax(1) = axes;

hold on

xlabel ('k');

ylabel ('C');

xlim([-2 2]);

ylim([0 40]);

dt = 0.01;

N = 250;

for k=-2:0.1:10

c = zeros(N+1,1);

c(1)= 23;

t(1) = 0;

for i=1:N

t(i+1) = t(i) + dt;

c(i+1) = c(i) + dt*((1/10)*((c(i)-23)*(25-c(i))*(c(i)-29))-k);

end

plot(ax(1),k,c,'color','blue','marker','.');

end

.

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Emily Tabb 2021-5-26

Thankyou so much for you're help I'm not sure why it is not looking more like a bifurcation diagram is there a major issue you can see in the coding? I'm just trying to plot a bifurcation diagram from this equation dc/dt = 1/10(C-23)(25-C)(C-29) - k

Thanks