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Re: [Bug-gsl]Bug in gsl_integration_qawc and correction
- From: Brian Gough <brian dot gough at network-theory dot co dot uk>
- To: Axel Hutt <hutt at wias-berlin dot de>
- Cc: bug-gsl at gnu dot org, gsl-discuss at sources dot redhat dot com
- Date: Thu, 9 Jan 2003 21:32:33 +0000
- Subject: Re: [Bug-gsl]Bug in gsl_integration_qawc and correction
- References: <3E1C5DE9.4ADFF807@wias-berlin.de>
Axel Hutt writes:
> there is a bug in the quadrature routine for Cauchy principal
> values in gsl_integration_qawc. The problem is, that for a special
> relation of integration interval (a,b) and singularity, the
> bisection routine in $(GSL-ROOT-DIR)/integration/qawc.c might lead
> to integration borders a1=c or b1=c, which yields NaN from
> qc25c(..) for the integral. This is easily resolved by changing
> the check in which subinterval c lies (line 133) from if (c > a1 &&
> c < b1) to if (c >= a1 && c <= b1) (or equivalently for a2 and b2
> in line 138), just add equation signs in qawc.c in line 133.
> Unfortunately, I do not know how to handle patch files, sorry for
> this.
Thanks for the bug report -- can you send a small example program
which demonstrates the problem.
best regards,
--
Brian Gough