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Re: [Help-gsl] gsl_sf_legendre_Plm_e sign error
From: |
Brian Gough |
Subject: |
Re: [Help-gsl] gsl_sf_legendre_Plm_e sign error |
Date: |
Mon, 15 Nov 2004 13:24:44 +0000 |
Robin Hankin writes:
> I'm working with Legendre functions and I'm trying to reproduce
> Abramowitz and Stegun's
> figure 8.2 which shows $P^1_n(x)$.
The figure in Abramowitz and Stegun is wrong (compare with
8.6.1)---the value from GSL is correct.
--
regards
Brian Gough
Network Theory Ltd,
Commercial support for GSL --- http://www.network-theory.co.uk/gsl/
------- start of forwarded message -------
From: Gerard Jungman <address@hidden>
To: Brian Gough <address@hidden>
Subject: Re: legendre bug?
Date: Fri, 12 Nov 2004 15:57:39 -0700
On Thu, 2004-11-11 at 10:08, Brian Gough wrote:
> Hello,
> P_1^1(0) should be 1 I think.
> See http://lists.gnu.org/archive/html/help-gsl/2004-11/msg00011.html
If you apply A+S 8.6.1, you get -1. This is consistent
with everything I have seen before as well. The function
legendre_Pmm() in legendre_poly.c implements a standard
formula for this. I'm not sure what A+S thought
they were plotting, but it is not what they say.
They may actually have plotted what they call P_{mm}, with
both indices downstairs. See the Notation section at the
very beginning of chapter 8.
I can't find the original email (from R. Hankin),
but maybe you have it and can forward this response
to him and/or the list.
--
Gerard Jungman <address@hidden>
Los Alamos National Laboratory
------- end of forwarded message -------
- [Help-gsl] gsl_sf_legendre_Plm_e sign error, Robin Hankin, 2004/11/10
- Message not available
- Re: [Help-gsl] gsl_sf_legendre_Plm_e sign error, Brian Gough, 2004/11/11
- Re: [Help-gsl] gsl_sf_legendre_Plm_e sign error,
Brian Gough <=
- Re: [Help-gsl] gsl_sf_legendre_Plm_e sign error, Robin Hankin, 2004/11/15
- [Help-gsl] a new wrapper for the GSL, Robin Hankin, 2004/11/18
- Re: [Help-gsl] a new wrapper for the GSL, Brian Gough, 2004/11/19
- Re: [Help-gsl] a new wrapper for the GSL, Robin Hankin, 2004/11/19
- Re: [Help-gsl] a new wrapper for the GSL, Andre Lehovich, 2004/11/19
- Re: [Help-gsl] a new wrapper for the GSL, Brian Gough, 2004/11/22
- [Help-gsl] problem with gsl_sf_elljac_e, Robin Hankin, 2004/11/24
- Re: [Help-gsl] problem with gsl_sf_elljac_e, Brian Gough, 2004/11/29