RE: Re: Lists and tables
- To: mathgroup at smc.vnet.net
- Subject: [mg36195] RE: [mg36105] Re: Lists and tables
- From: "Annetts, Dave (E&M, North Ryde)" <David.Annetts at csiro.au>
- Date: Mon, 26 Aug 2002 04:16:21 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Hi Jerry,
> 1) Get data from excel into a coordinate
> list {x,y,z}
> e.g. Node 1, {x1,y1,z1}
> Node 2, {x2,y2,z2}
> etc...
Why not just use
data = ReadList["filename", Table[Number, {4}]];
Alternatively,
data = ReadList["filename", Number, RecordLists->True];
data = Partition[data, 4];
cord = {#[[1]], #[[2]], #[[3]]}& /@ data;
> 2) Convert from Rectangular to
> Cylindrical (maybe)
Coordinate tranforms live in Calculus`VectorAnalysis`. It's straightforward
to write a function that uses
CoordinateFromCartesian[{#[[1]], #[[2]], #[[3]]}, Spherical]& /@ cord;
> 3) Plot3D the data
This will be tricky -- ListSurfacePlot3D plots f[x, y]. ListContourPlot3D
which plots f[x, y, z] can be quite slow.
>
> 4) Generate a harmonic bessel function for that
> plot3D/graph
>
> 5) Find the equation(s) that spits out
> these harmonic
> bessel functions (which I think might be in the general form
> of Hankel
> Function solutions to the Helmholtz equation which shows
> cylinder harmonics
> of order "v")
Maybe I misunderstand ... isn't this the same as fitting a bessel function
to your data? For this, you can use Statistics`NonlinearFit`.
> I can figure out step 5 if I can get steps 1 through 4
> figured out. If
> anyone can write a recipe for me to follow that would be
> great, or even some
> tips and clues...Anything!!!
Regards,
Dave.