problem plotting 3d function

2 次查看（过去 30 天）
Elinor Ginzburg
Elinor Ginzburg 2021-5-23
评论： Sulaymon Eshkabilov 2021-5-23
Hello,
I'm trying to plot a 3-d function. I saw there are many questions about it, but I didn't found the answer I needed. I'm trying to plot the following function: where ,
and also ,
unfortunately, in the plot I get, my function is constant in ϕ which is weird since it is affected by it. I think I defined my axis in a wrong way. perhaps anyone has an idea what could be the problem? here's my code:
% set parameters
theta = linspace(0,pi);
phi = linspace(0,2*pi);
delta = ( (sin(theta).^2) .* sqrt(1 - 2 .* cos(2*phi) .* ((cot(theta)).^2) + ((cot(theta)).^4) ) );
eig1 = 0.5.*(1+delta);
eig2 = 0.5.*(1-delta);
% entanglement entropy function
Eentropy = -(eig1.*log(eig1) + eig2.*log(eig2));
% reshape vector into matrix to fit data size for surf() function. X,Y
% vectors are 100x100 where Eentropy is 1x100 thus need to replicate it 100
% times as rows and 1 time as column
Eentropy = repmat(Eentropy,100,1);
% draw surface and add axis titles
surf(Eentropy);
xlabel("\phi [rad]");
ylabel("\theta [rad]");
zlabel("z axis");
title("Entanglement Entropy");
and here's the plot:
Thank you very much for your help!

请先登录，再回答此问题。

采纳的回答

Sulaymon Eshkabilov
Hi
Here is the corrrected code.
theta = linspace(0,pi);
phi = linspace(0,2*pi);
[theta, phi]=meshgrid(theta, phi);
delta = ( (sin(theta).^2) .* sqrt(1 - 2 .* cos(2*phi) .* ((cot(theta)).^2) + ((cot(theta)).^4) ) );
eig1 = 0.5*(1+delta);
eig2 = 0.5*(1-delta);
% entanglement entropy function
Entropy = -(eig1.*log(eig1) + eig2.*log(eig2));
surf(phi, theta, Entropy);
xlabel("\phi [rad]");
ylabel("\theta [rad]");
zlabel("z axis");
title("Entanglement Entropy");

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Numerical Integration and Differentiation 的更多信息

标签

产品


版本

R2020b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by