Problem in contour plot using ''for '' loop.

Question

AVM 2020-6-24

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/553945-problem-in-contour-plot-using-for-loop

评论： KSSV 2020-6-24

I would like to get a contour plot in the following code, but some prolem is occuring. Please somebody help me to solve that.

clc;
syms t g
n=6;
I1=eye(n);
I2=eye(2);
matdimension= n-1;
tempvector = 0:1:matdimension;
tempvector = sqrt(tempvector);
tempmatrix = diag(tempvector);
anni= circshift(tempmatrix,-1);
crea = anni';
num=crea*anni;
c=crea+anni;
sigx=[0,1;1,0];
t=0:0.01:1;
g=0.0001:0.01:0.49;
M= zeros(size(t));
for i = 1:length(t) 
    for k=1:length(g)
      A= g(k).*kron(I2,num)+ t(i)*kron(sigx,c);
   
      
    [~,v]=eig(A);
    M(i)=v(2,2); 
   
    [T,G]=meshgrid(t,g); %%%%%%%%%% upto this line it is working......
     F=M(T,G); %%%%%% for here the problem is starting.
     
    end
end
contourf(T,G,F)
colormap(cool)
%%%%%%%%%%%%%%output error
Index in position 1 is invalid. Array indices must be positive integers or logical values.
Error in tial (line 35)
     F=M(T,G); 

2 个评论
显示无隐藏无

KSSV 2020-6-24

在 MATLAB Online 中打开

What is the purpose of this?

F=M(T,G); %%%%%% for here the problem is starting

Offcourse, it will give error...

AVM 2020-6-24

编辑：AVM 2020-6-24

Actually I need to see how the contour plot looks like in this case and I have to compare it with other system of equations.

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

KSSV 2020-6-24

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/553945-problem-in-contour-plot-using-for-loop#answer_456469

在 MATLAB Online 中打开

May be you are looking for

contour(T,G,M)

2 个评论
显示无隐藏无

AVM 2020-6-24

Actually by anyway I need to plot that contour (t,g,m). I thought that some meshgrid has to be assigned first within the for loop and define M as M(T,G). But it is not woking. Please, help me to get that. I do this using foor loop because the eigenvalue calculation is taking long time symbolically. It will take even more time if I increase the dim. of the matirx A.