Re: [Help-gsl] Questions about BFGS2 algorithm implemented for the GSL

[Brian Gough]

At Fri, 23 May 2008 11:44:55 -0600,
Sanjay Bhatnagar wrote:
>      if ((a-alpha)*fpa <= GSL_DBL_EPSILON) {
>        /* roundoff prevents progress */
>        fprintf(stderr,"linear min. no prog: %e %e %e
> %e\n",a,alpha,fpa,GSL_DBL_EPSILON);
>        return GSL_ENOPROG;
>      };
> 
> The message printed was:
> 
>     linear min. no prog: 1.498441e-01 1.498441e-01 3.012037e-02 2.220446e-16
> 
> Does anyone know what could be wrong?  

a == alpha (?)  Take a look further up in the code where alpha (the
iterpolated minimum) is computed. Apparently the interpolation is
failing to move away from the point "a".

-- 
Brian Gough

GNU Scientific Library -
http://www.gnu.org/software/gsl/