Re: [Bug-gsl] UNEXPECTED BUG in gsl_sf_lngamma_sgn_e !

[Nenad Sakan]

I have analysed myself the code.

First of all, I hav compiled gsl 1.9 on gnu linux (slackware) x86 processor.
By some mistake the debugger had pointed me to the previous value of the 
epsilon (not the real where it calls the lngama with x = 0). I have started 
to print out each parameter that goes to the function and noticed that realy 
it does not break for x != 0, what is expected). 

I have tested it after that with a simple routine where I have passed the 
value that GDB pointed out and noticed that all goes well (that is also 
expected). For some reason backtrace in GDB has printed the value for 1F1 and 
further on which is not the step at which error occured but one before!?!?

Concerning my code, I have made some calculations for photoabsorption in 
dense hydrogen plasma (Debye radius comparable to self sphere), and it is 
quite large (approx 6500 - 7000 lines now). I could say that gsl has saved me 
quite a lot effort and thanks to Your team I have managed to do some nice 
work. I have denoted in my masters degree thesis that I have used Your 
library, and as soon as I finish my PHd I will do it also.

I have noticed that I will need some optimization in root finding function 
since I have used an analiticaly solvable QM potential model for the plasma-
ion-electron innteraction and basicaly I am using some nonsofisticated root 
finding algorhytm of my own for the analitical solution numericaly.

As soon as I publish some paper from this work I might send it ti You if You 
would like.

Thank You for the fast response.
Thank You once again for a nice work on GSL library

Sincerely Yours

Nenad Sakan

-----------------
Institute of Physics, Belgrade
http://www.phy.bg.ac.yu/


---------- Original Message -----------
From: Brian Gough <address@hidden>
To: "Nenad Sakan" <address@hidden>
Cc: address@hidden
Sent: Thu, 31 May 2007 11:02:24 +0100
Subject: Re: [Bug-gsl] UNEXPECTED BUG in gsl_sf_lngamma_sgn_e !

> At Wed, 30 May 2007 14:45:43 +0200,
> Nenad Sakan wrote:
> > 
> > I had some problem with the hypergeometric functions that I use.
> > when I debug the program an run backtrace the error occures at the
> > point before call to lngamma_sgn_sing (gamma.c: leatle before
> > 1240). By all possible logic eps SHOULD NOT BE 0 at this point
> > (x=0.0001139406357036744).
> 
> Hello,
> 
> Please can you send a small example program that demonstrates the
> problem, and details of your operating system, compiler and version 
> of GSL. Thank you.
> 
> -- 
> Brian Gough
> 
> Network Theory Ltd,
> Publishing Free Software Manuals --- http://www.network-theory.co.uk/
------- End of Original Message -------