[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: normalized ALF (Assotiated Legendre Function)
From: |
Ben Abbott |
Subject: |
Re: normalized ALF (Assotiated Legendre Function) |
Date: |
Mon, 11 Feb 2008 06:50:42 -0500 |
On Feb 11, 2008, at 3:01 AM, kruvalig wrote:
Thank's a lot for quick answer. I very suprised of it.
On Sun, 10 Feb 2008 01:37:10 +0300, Ben Abbott <address@hidden>
wrote:
I've posted a patch and changelog to the maintainers list. Attached
to
this
email is the modified script.
http://www.nabble.com/file/p15391002/legendre.m legendre.m
Can any one test output of this file and output matlab file to high
degree
(>70).
result_mlab=legendre(80,[-1:0.1:1], "norm");
result_octave=legendre(80,[-1:0.1:1], "norm");
max(max(abs(result_mlab-result_octave)))
warning: legendre is unstable for higher orders
ans = 1.4343e+16
This is what I get.
Here ftp://77.108.213.161/result_octave_80 is a file, generated in
octave
by code:
result_octave=legendre(80,[-1:0.1:1], "norm");
save -v7 result_octave_80
I think this code
scale = (-1).^m .* sqrt ((n+0.5) .* factorial (n-m) ./ factorial (n
+m));
whill give bad answer in high order of legendre.
And we have to write: To what order it compute in right.
I'm not so sure a problem lies with the normalization. When I compare
results for legendre(80, [-1:0.1:1]), I get
warning: legendre is unstable for higher orders
ans = 5.4154e+126
I haven't looked into the details as how this function works yet. I'll
do that today.
In any event, can you (someone else?) propose a change? ... or a
reference for how it should be done?
Ben
- normalized ALF (Assotiated Legendre Function), kruvalig, 2008/02/04
- Re: normalized ALF (Assotiated Legendre Function), kruvalig, 2008/02/11
- Re: normalized ALF (Assotiated Legendre Function),
Ben Abbott <=
- Re: normalized ALF (Assotiated Legendre Function), Marco Caliari, 2008/02/11
- Re: normalized ALF (Assotiated Legendre Function), Ben Abbott, 2008/02/11
- Re: normalized ALF (Assotiated Legendre Function), Dmitri A. Sergatskov, 2008/02/12
- Re: normalized ALF (Assotiated Legendre Function), Ben Abbott, 2008/02/12
- Re: normalized ALF (Assotiated Legendre Function), Marco Caliari, 2008/02/12
- Re: normalized ALF (Assotiated Legendre Function), Marco Caliari, 2008/02/12
- Re: normalized ALF (Assotiated Legendre Function), Ben Abbott, 2008/02/12
- Re: normalized ALF (Assotiated Legendre Function), Ben Abbott, 2008/02/12
- Re: normalized ALF (Assotiated Legendre Function), Ben Abbott, 2008/02/12
- Re: normalized ALF (Assotiated Legendre Function), Marco Caliari, 2008/02/13