This is the mail archive of the
gsl-discuss@sources.redhat.com
mailing list for the GSL project.
Re: negative absolute error given by qag?
- From: Francisco J Molina <FJMolina at lbl dot gov>
- To: Brian Gough <bjg at network-theory dot co dot uk>, "gsl-discuss at sources dot redhat dot com" <gsl-discuss at sources dot redhat dot com>
- Date: Wed, 01 May 2002 16:48:48 -0700
- Subject: Re: negative absolute error given by qag?
- Organization: Lawrence Berkeley National Laboratory
- References: <3CCF1B47.3FE2F052@lbl.gov> <15568.21718.699042.48684@debian>
Brian Gough wrote:
>
> Francisco J Molina writes:
> > I am using the function
> > gsl_integration_qag
> > Is it possible that this function returns an absolute error (
> > abserr ) that is negative.
> > I have been reading the code of qag.c and that seems to be the
> > case.
> > Anyone could confirm this?
>
It was my mistake. Negative errors are not occuring when I use qag.
Do you know how I can avoid the error:
roundoff error prevents tolerance from being achieved?
> Hi,
>
> Negative errors shouldn't occur under normal usage, so if you
> encounter any negative errors please send a bug report. Thanks.
>
> > How can I avoid a message of this type:
> > gsl: qag.c:257: ERROR: maximum number of subdivisions reached
> > I am know in the world of C++. Does anyone which is the basic tool
> > in C++ to handle exceptions/errors?
>
> You can use the function gsl_set_error_handler_off() at the beginning
> of your program, and then the return status of gsl functions for
> errors.
>
> regards
> Brian Gough