MaplePrimes - answers and comments on Question, 3d plotting cylindrical co-ordinates

3d plotting cylindrical co-ordinates

hirnyk — Tue, 16 Mar 2010 19:34:27 Z

Do you look at Maple 13 Help/ Table of Contents/ Graphics/ 3-D/ ?addcoords , Examples ?

Yup, I've checked the

robmichaels — Tue, 16 Mar 2010 21:34:16 Z

Yup, I've checked the examples. I am now getting a non-plot, rather than an error message, I needed to square it to get rid of the imaginary exponentials, but I still don't get anything

Cheers Robert, we're getting

robmichaels — Tue, 16 Mar 2010 23:57:23 Z

Cheers Robert, we're getting closer, I'm getting a shape now although it's rocket shaped rather than donut shaped

Still not working

robmichaels — Wed, 17 Mar 2010 22:54:32 Z

Some remarks

hirnyk — Thu, 18 Mar 2010 00:22:45 Z

1. I do not see the dependence of abs(u(r,teta,z)) on teta at all.

2. If 0.01<=r<=1 and w(0)=35*10^(-9), then the term r/w(0)^2*exp(-r^2/w(0)^2) is at most

10^15*exp(-10^3)=5*10^(-420). It seems strange.

What to plot

Robert Israel — Tue, 16 Mar 2010 22:26:25 Z

First of all, make sure the function you're trying to plot will give numerical values when given numbers for r, theta, z. If you gave us the actual Maple input, we might be able to help with that.

Second, what sort of a plot are you looking for? You have a function of three variables. It should give you a value at each point of three-dimensional space.
It's impossible to plot that directly (the graph would have to be a four-dimensional object). You might, for example, plot the surface f(r, theta, z) = c for some constant c. This could be done using implicitplot3d in the plots package. For example:

> plots[implicitplot3d](r^2*sin(theta)^2*exp(-r^2-z^2) = 1/10,
   r = 0 .. 2, theta = -Pi .. Pi, z = -2 .. 2,  
   coords=cylindrical,  view=[-2..2,-2..2,-2..2],  
   axes=box, labels=[x,y,z], style=patchcontour,
   grid=[40,40,40],orientation=[30,60]);

Note: because of a bug, this doesn't work properly without the view option.