# 3D Plotting in matlab

8 views (last 30 days)
P Maity on 18 Jan 2020
Commented: P Maity on 23 Jan 2020
I have got a function after integration in Matlab, f($\theta$,$g$) which is a complex function. I would like to get 3D plot the this function with respect to $\theta$ and g, where $g$ positive integer runs from 0 and $\theta$ runs from 0 to $\pi$. The function is very large and complicated one. Pl hep me to plot this.

Walter Roberson on 23 Jan 2020
It is disappointing that you deleted the further discussion and contributions from the volunteers :(
P Maity on 23 Jan 2020
@walter: ...I am really Sorry for my nonsense activities. Actually, I did not under stand what was acttally going on. I thought that as I asked you people so many times regarding my corrections and rectifications, so better to clear my all these garbage kind of thing so that some important and summary conversation remain. But I really didn't understand that it actually causes some harmful to you.
Sorry for my activities once again. Pl pardon me if possible.

Star Strider on 18 Jan 2020
I assume ‘complex’ just means complicated, and not a function with real an imaginary arguments or output. If it is actually complex in the mathematical sense, a slightly different procedure than that presented here would be necessary.
Try something like this:
theta = linspace(0, pi, 50);
g = linspace(0, 100, 50);
[Th,G] = ndgrid(theta, g);
F = f(Th,G);
figure
mesh(Th, G, F)
grid on
Make appropriate changes to get the result you want.

Show 1 older comment
Star Strider on 18 Jan 2020
I am not following what you’re doing in your code.
The result needs to be a function of θ andg. Then you can use the techniques I described to plot it.
Walter Roberson on 19 Jan 2020
What result are you expecting for theta = 0 leading to division by sin(0)?
Walter Roberson on 19 Jan 2020
%% Now I need to perform that integration of phi and make a 3d plot of that result with
theta and alpha , aplha is a real integer runs from 0 to ...and theta from 0 to pi.
The integration of phi? But phi is one of your input variables, not an output formula.
Which of your formulas is to be integrated with respect to what? What should be a long the two independent axes? As you indicate that alpha is an integer, it sounds as if alpha is not one of your independent variables.
Your r is complex valued. Are you looking to plot the real or the imaginary part or are you looking to plot the absolute value?