Re: [Help-gsl] gsl_integration_qawf

[Patrick Alken]

Hello,

  A return code of 0 is equivalent to GSL_SUCCESS, so yes that is good.
I'm not sure what you mean by inner/outer integration - can you provide
a minimal working source code to demonstrate the problem you're having?

  The adaptive integration routines in GSL are based on QUADPACK - you
can find further documentation on QAWF here:
http://www.netlib.org/quadpack/doc.
There is also an example calling program for QAWF on that page (in
fortran), perhaps it will help you.

  Thanks for the whitespace issue - I have fixed it on the git.

Patrick

On 01/15/2018 01:35 AM, Richard Hartmann wrote:
> Hi
>
> I'm struggling with the numeric Fourier integration, in particular
> with the error handling of the 'gsl_integration_qawf' routine.
>
> As of the nested integration and if the error handling is default, my
> test aborts since the inner integration reports a roundoff error.
> (current Git 3bbe65ad5a07362e82103b311feda55d4355a2fe, qawf.c l. 133)
>
> So far so good, however, if the error handling is off, the outer
> integration seem to run through. The overall return code is 0,
> indicating success. Is that intensional?
>
> I tried to answer the question my self, but I could not understand
> what the 'gsl_integration_qawf' routine was doing.
>
>
> Secondly and very minor, there is a 'space' missing in the error
> message at qawo.c l. 104
>
>       GSL_ERROR ("cannot reach tolerance because of roundoff error"
>                  "on first attempt", GSL_EROUND);
>
> should be
>       GSL_ERROR ("cannot reach tolerance because of roundoff error "
>                  "on first attempt", GSL_EROUND);
>
>
> Thanks for this great library and thanks for you help.
> Richard
>