How to use the result of my matrix calculation to create 2D plot

Question

Jun Xiao 2019-10-31

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/488546-how-to-use-the-result-of-my-matrix-calculation-to-create-2d-plot

评论： Daniel M 2019-11-1

I tried to plot my the result of my matrix calculation. However, my matlab said that my calculation result lambda1 or Z is not a matrix so I cannot plot without using the command plot3. But I have to plot the 2D figure with different colors represent different result of lambda1. And the commands like pcolor and color require my results to be matrix. What should I do?

n1 = 1.5;

n2 = 3.0;

b1 = 8*10.^(-18);

c1 = pi*10.^(-13);

k1 = (2*pi)*n1;

k2 = (2*pi)*n2;

d1 = [1 1; k1 -k1];

d2 = [1 1; k2 -k2];

t1 = inv(d1);

t2 = inv(d2);

for l1= 1:0.1:10

for l2= 1:0.1:10

p2= [exp(i*k2*l2) 0; 0 exp(-i*k2*l2)];

p1= [exp(i*k1*l1) 0; 0 exp(-i*k1*l1)];

M = t1*d2*p2*t2*d1*p1;

M1= real(M);

[X,Y]= eig(M1);

lambda1 = [0 1]*Y*[0;1];

lambda2 = real([1 0]*Y*[1;0]);

Z = lambda1;

hold on

end

pcolor(l1,l2,Z)

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

KALYAN ACHARJYA 2019-10-31

编辑：KALYAN ACHARJYA 2019-10-31

Formulate the question in an easy way so that it can be understood easily.

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Daniel M 2019-10-31

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/488546-how-to-use-the-result-of-my-matrix-calculation-to-create-2d-plot#answer_399165

l1,l2, and Z are all a single value. You need to understand how to store values in a for loop:

https://www.mathworks.com/help/matlab/ref/for.html

2 个评论
显示无隐藏无

Jun Xiao 2019-11-1

Thank you for the instruction. I know how to store value Z in a for loop now. But, I still don't know why my variants l1 and l2 cannot be stored as common for loop always did. Can you point it for me?

Daniel M 2019-11-1

Those variables don't really exist outside of the for loop. They look like vectors, but they're not. Their value is only the value of that iteration, and therefore outside of the loop they only keep the value of the last iteration. Just recreate them after the loop.

请先登录，再进行评论。