MATLAB Central Newsreader - Plotting 3-d functions (Spherical Harmonics)

Plotting 3-d functions (Spherical Harmonics)

Christopher Hart — Thu, 16 Apr 2009 15:00:19 -0400

So I've had little experience with Matlab and I'm finding it difficult to plot a 3-d Spherical harmonic wave in polar coordinates. In Mathmatica this isn't a difficult thing to do but my lack of experience with Matlab is posing as an issue. My Modern Physics instructor would like us to plot the following Normalized Spherical Harmonic functions. Any help would be appreciated. Please give specific details because I still don’t know many of the commands. Thanks!

Here is the url for the functions. I simply scanned them in instead of manually typing them out:
http://farm4.static.flickr.com/3361/3447815798_3c2b8b8067.jpg?v=0

Re: Plotting 3-d functions (Spherical Harmonics)

TideMan — Fri, 17 Apr 2009 02:36:01 -0400

On Apr 17, 3:00=A0am, "Christopher Hart" <char...@hotmail.com> wrote:
> So I've had little experience with Matlab and I'm finding it difficult to=
plot a 3-d Spherical harmonic wave in polar coordinates. =A0In Mathmatica =
this isn't a difficult thing to do but my lack of experience with Matlab is=
posing as an issue. =A0My Modern Physics instructor would like us to plot =
the following Normalized Spherical Harmonic functions. =A0Any help would be=
appreciated. =A0Please give specific details because I still don=92t know =
many of the commands. =A0Thanks! =A0
>
> Here is the url for the functions. =A0I simply scanned them in instead of=
manually typing them out:http://farm4.static.flickr.com/3361/3447815798_3c=
2b8b8067.jpg?v=3D0

I don't understand.
If it's so easy to do in Mathmatica (sic), then why don't you use that
instead of Matlab?

Unless, of course, your "Modern Physics instructor" wants you to learn
Matlab, using this as an exercise. If this is the case, then why are
you asking us? You should do your own homework.

Re: Plotting 3-d functions (Spherical Harmonics)

Christopher Hart — Fri, 17 Apr 2009 03:21:01 -0400

You're right my instructor is looking to get us familiarized with Matlab. I’m horrible with software like this which is why I was looking here for some help because I can’t figure it out. I was hoping for a little bit of help but apparently people want to be jerks about asking a question. I wasn’t looking for someone to do my homework for me. I was looking for someone to direct me in the right direction but apparently that’s too much to ask. Apparently Tideman you’re not one who has ever asked for help. Instead of posting destructive criticism why not just post nothing at all. Jerk!

Re: Plotting 3-d functions (Spherical Harmonics)

TideMan — Fri, 17 Apr 2009 03:39:42 -0400

On Apr 17, 3:21=A0pm, "Christopher Hart" <char...@hotmail.com> wrote:
> You're right my instructor is looking to get us familiarized with Matlab.=
=A0I=92m horrible with software like this which is why I was looking here =
for some help because I can=92t figure it out. =A0I was hoping for a little=
bit of help but apparently people want to be jerks about asking a question=
. =A0I wasn=92t looking for someone to do my homework for me. =A0I was look=
ing for someone to direct me in the right direction but apparently that=92s=
too much to ask. =A0Apparently Tideman you=92re not one who has ever asked=
for help. =A0Instead of posting destructive criticism why not just post no=
thing at all. Jerk!

Oh, I see. I'm sorry. I must have misinterpreted this statement of
yours:
"Please give specific details because I still don=92t know many of the
commands."
If you are just "looking for someone to direct me in the right
direction", what did you mean by asking for "specific details"?

But it's Friday afternoon here and I'm feeling generous, so here is a
hint that will direct you in the right direction, as requested: RTFM

Re: Plotting 3-d functions (Spherical Harmonics)

Ken Garrard — Fri, 17 Apr 2009 14:24:01 -0400

"Christopher Hart" <chart47@hotmail.com> wrote in message <gs7h63$otc$1@fred.mathworks.com>...
> So I've had little experience with Matlab and I'm finding it difficult to plot a 3-d Spherical harmonic wave in polar coordinates. In Mathmatica this isn't a difficult thing to do but my lack of experience with Matlab is posing as an issue. My Modern Physics instructor would like us to plot the following Normalized Spherical Harmonic functions. Any help would be appreciated. Please give specific details because I still don’t know many of the commands. Thanks!
>
> Here is the url for the functions. I simply scanned them in instead of manually typing them out:
> http://farm4.static.flickr.com/3361/3447815798_3c2b8b8067.jpg?v=0

One approach to you homework ...

1) create a grid of elevation and azimuth angles
help meshgrid

2) calculate the radius of the desired spherical harmonic points over the grid
help legendre

3) convert elevation, azimuth and radius to Cartesian
help sph2cart

4) produce a 3D surface plot
help surf

Ken

Re: Plotting 3-d functions (Spherical Harmonics)

Chris — Mon, 20 Apr 2009 15:21:02 -0400

Thanks Ken I appreciate the help. It helped alot....

"Ken Garrard" <ken_garrardAT@ncsuDOT.edu> wrote in message <gsa3e0$79b$1@fred.mathworks.com>...
> "Christopher Hart" <chart47@hotmail.com> wrote in message <gs7h63$otc$1@fred.mathworks.com>...
> > So I've had little experience with Matlab and I'm finding it difficult to plot a 3-d Spherical harmonic wave in polar coordinates. In Mathmatica this isn't a difficult thing to do but my lack of experience with Matlab is posing as an issue. My Modern Physics instructor would like us to plot the following Normalized Spherical Harmonic functions. Any help would be appreciated. Please give specific details because I still don’t know many of the commands. Thanks!
> >
> > Here is the url for the functions. I simply scanned them in instead of manually typing them out:
> > http://farm4.static.flickr.com/3361/3447815798_3c2b8b8067.jpg?v=0
>
> One approach to you homework ...
>
> 1) create a grid of elevation and azimuth angles
> help meshgrid
>
> 2) calculate the radius of the desired spherical harmonic points over the grid
> help legendre
>
> 3) convert elevation, azimuth and radius to Cartesian
> help sph2cart
>
> 4) produce a 3D surface plot
> help surf
>
>
> Ken