Re: [Help-gsl] gsl_multimin_fminimizer_set fails to return

[Brian Hawkins]

Stephen,

The set routine does little more than call the objective function at the
initial guess x0 and at x0+dx for each dx in the initial step sizes.  Have
you verified that the MPI objective function works with these parameters?
 Is there any diagnostic information besides a missing print output (e.g.,
segfault or backtrace).

As an aside, I see lots of vector alloc calls but none to free.  Are you
using some C++ wrapper for GSL?

Regards,
Brian

On Thu, Aug 30, 2012 at 9:00 AM, <address@hidden> wrote:
>
>
> Hello,
>
> I am working on a project using GSL to minimize a function, where this
> function calls MPI to do the actual computation. I have both an MPI and a
> non-MPI version of the objective function. When I use the non-MPI version,
> everything seems to work. However, when I use the MPI version,
> gsl_multimin_fminimizer_set fails to run ("passed set" never prints)
>
>   cout << "GSL: " << "Starting minimizer" << endl;
>   S = gsl_multimin_fminimizer_alloc(T, MODEL_VALUE_COUNT);
>   cout << "GSL: passed alloc"  << endl;
>   gsl_multimin_fminimizer_set(S, &MinexFunc, StartVec, StepVec);
>   cout << "GSL: passed set" << endl;
>
> The full code is available at https://gist.github.com/3522278
>
> The non-mpi version code from 596 to 613 runs just as I would want it to.
> However, the MPI equivalent (lines 622 to 650) do not. I would really
> appreciate some feedback as to why this isn't working as I would expect. I
> know that the mpi objective function (nll_mpi, which is wrapped by
> SolveEnergy).
>
> Thanks,
> Stephen
>