MATLAB: How to “surf” over a circular domain

MATLABpdesurf

I have some code that looks at the behavior for various Bessel functions. I would like to plot this over a sector of angle a, this angle I can change as I wish. I have no idea where to start, everywhere I look it refers me to PDE toolbox.

Best Answer

It is my understanding that you are trying to create a 3-D surf plot of a function, which is calculated over a circular domain, instead of a rectangular domain.
You can use the “meshgrid” function to generate the arguments for the “surf” function. For circular domains, you can pass Radius and polar angle range as arguments to generate the grid. Then, generate the new matrices in Cartesian coordinates using the obtained grid. I am including a small example below, which might help you understand the technique.
%Generate the Polar angle vector containing information about sector location and angle
Theta = [pi/5:0.01:pi/2];  
%Generate the Radius vector
R = [0:0.001:1.0];
%Create a grid from angle and Radius
[ThetaG,RG] = meshgrid(Theta,R);
%Create X,Y matrices calculated on grid.
X = RG.*cos(ThetaG);
Y = RG.*sin(ThetaG);
%Calculate the function
Z = X.^2 + Y.^2;
%Surf plot
surf(X,Y,Z);
I hope this helps you in solving the problem.
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