Figure 's issue

Question

M 2022-9-12

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1803170-figure-s-issue

编辑： Torsten 2022-9-13

Hi everyone. I wrote the code below for plotting a 2d figure (ct-h) but it doesn't work; I mean it doesn't show any figure. Could you please tell me what is the problem, and how can I solve it?

Thanks in advance for any help.

vplc=0.16;
delta=0.1;
Ktau=0.045;
Kc=0.1; 
K=0.0075;
Kp=0.15;
gamma=5.5;
kb=0.4;
vss=0.044;
alpha0=delta*6.81e-6/(0.002);
alpha1=delta*2.27e-5/(0.002);
Ke=7;
Vs=0.002;
ks=0.1;
Kf=0.18;
kplc=0.055;
ki=2;
[ct]=meshgrid(0.0001:0.05:30);
x=(((2.*Vs.*K.*gamma.^2.*ct.^2)./(vss))+((2.*alpha0.*ks.^2)./(vss))+((2.*Ke.^4.*ks.^2.*alpha1)./(vss.*(Ke.^4+(gamma.*ct).^4))));
p=(vplc./ki).*(x./((kplc).^2+x));
A=(-(vss.*x)./(ks.^2))+((Vs.*K.*gamma.^2.*ct.^2)./(ks.^2))+alpha0+alpha1.*((Ke.^4)./(Ke.^4+(gamma.*ct).^4));
h=-(0.4.*A.*((Kc.^4).*(Kp.^2))./((p.^2.*x.^2.*gamma.*ct.*Kf)));
plot(ct,h); 

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Answer 1

Walter Roberson 2022-9-12

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https://ww2.mathworks.cn/matlabcentral/answers/1803170-figure-s-issue#answer_1051530

编辑：Walter Roberson 2022-9-12

在 MATLAB Online 中打开

[ct]=meshgrid(0.0001:0.05:30);

is treated the same way as if you had used

[ct, ~]=meshgrid(0.0001:0.05:30, 0.0001:0.05:30);

It creates a 600 x 600 grid that is just a lot of repeats of the same values. So you end up plotting 600 lines.

I suggest you use semilogy instead of plot()

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Torsten 2022-9-12

编辑：Torsten 2022-9-13

在 MATLAB Online 中打开

With "plot(ct,h)" also worked and gave me the figure that I expected

I only see one small jump at 0 and everything else on the zero level

vplc=0.16;

delta=0.1;

Ktau=0.045;

Kc=0.1;

K=0.0075;

Kp=0.15;

gamma=5.5;

kb=0.4;

vss=0.044;

alpha0=delta*6.81e-6/(0.002);

alpha1=delta*2.27e-5/(0.002);

Ke=7;

Vs=0.002;

ks=0.1;

Kf=0.18;

kplc=0.055;

ki=2;

ct=0.0001:0.05:2;

x=(((2.*Vs.*K.*gamma.^2.*ct.^2)./(vss))+((2.*alpha0.*ks.^2)./(vss))+((2.*Ke.^4.*ks.^2.*alpha1)./(vss.*(Ke.^4+(gamma.*ct).^4))));

p=(vplc./ki).*(x./((kplc).^2+x));

A=(-(vss.*x)./(ks.^2))+((Vs.*K.*gamma.^2.*ct.^2)./(ks.^2))+alpha0+alpha1.*((Ke.^4)./(Ke.^4+(gamma.*ct).^4));

h=-(0.4.*A.*((Kc.^4).*(Kp.^2))./((p.^2.*x.^2.*gamma.*ct.*Kf)));

plot(ct,h);

whereas the semilogy option gives a good resolution of the different scales: