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Re: gsl: discrete Hankel transform
From: |
Francis Poulin |
Subject: |
Re: gsl: discrete Hankel transform |
Date: |
Fri, 4 Oct 2013 15:46:02 +0000 |
Hello,
I am happy to give it a try. Unfortunately, when I load bim and try the first
line I get an error,
octave-3.6.4:4> msh = msh2m_gmsh ("circle", "clscale", ".1");
Generating mesh...
error: msh2m_gmsh: the gmesh subprocess exited abnormally
error: called from:
error: /sw/share/octave/3.6.4/packages/msh-1.0.8/msh2m_gmsh.m at line 83,
column 5
If it worked easily I'd be happy to try it. I admit that I've looked into bim
before and was very attracted to its potential, unfortunately it doe seem hard
to get into initially.
Francis
On 2013-10-04, at 7:48 AM, c. <address@hidden> wrote:
>
> On 4 Oct 2013, at 12:59, Francis Poulin <address@hidden> wrote:
>
>> Hello,
>>
>> I am trying to solve Poisson's equation on a circular disk and thought I
>> might try the Discrete Hankel Transform that is part of gsl. I have gotten
>> as far as loading the package. I found some documentation for gsl that
>> gives some information but these commands don't they don't seem to be in
>> octave (after I pkg load gsl-oct364).
>>
>> http://www.gnu.org/software/gsl/manual/html_node/Discrete-Hankel-Transform-Functions.html#Discrete-Hankel-Transform-Functions
>>
>> Does anyone have any example files I could use to learn about how to do this
>> in octave?
>>
>> Cheers, Francis
>
>
> If you don't need to stick to exactly that method for solving Poisson's
> equation,
> here is a simple example of how to solve it with the bim package [1]:
>
>>> msh = msh2m_gmsh ("circle", "clscale", ".1");
>>> msh = bim2c_mesh_properties (msh);
>>> A = bim2a_laplacian (msh, 1, 1);
>>> b = bim2a_rhs (msh, 1, 1);
>>> dnodes = bim2c_unknowns_on_side (msh, [1 2]);
>>> inodes = setdiff (1:columns(msh.p), dnodes);
>>> u = zeros (columns (msh.p), 1);
>>> u(inodes) = A(inodes, inodes) \ (b(inodes) - A(inodes, dnodes) * u(dnodes));
>>> close all
>>> graphics_toolkit fltk
>>> pdesurf (msh.p, msh.t, u)
>
> you might also want to take a look at the new fem-fenics package [2,3].
>
> c.
>
> [1] http://wiki.octave.org/Bim_package
> [2] http://wiki.octave.org/Fem-fenics
> [3] http://wiki.octave.org/Fem-fenics#Poisson_Equation
>