Re: [Boost-mpi] Fwd: mpi: MPI_MAX_LOC

Subject: Re: [Boost-mpi] Fwd: mpi: MPI_MAX_LOC
From: Matthias Troyer (troyer_at_[hidden])
Date: 2013-10-14 05:39:56

Look at the documentation of MPI_MAX_LOC. The datatype of to be reduced needs to be a pair, consisting of value and index. You can do the same with your custom function.

On 14 Oct 2013, at 11:02, MM <finjulhich_at_[hidden]> wrote:

> That will give me the optimum value of  f(x1, ..., xn) but not _which_ (x1,....xn) gives that optimum evaluation of f.
> 
> MM
> 
> 
> On 14 October 2013 09:57, Matthias Troyer <troyer_at_[hidden]> wrote:
> 
> On 14 Oct 2013, at 10:53, MM <finjulhich_at_[hidden]> wrote:
> 
>> Hello
>> In a problem of getting the maximum of a multi-variable function, I would use mpi::reduce and provide it with a function object that compares the evaluations of this function.
>> 
>> Each process evaluates a part of the space, ie a number of n-tuples of the n-dimension space.
>> 
>> How do I get the n-tuple that yields the max of f(), given that MPI_MAXLOC is not available in boost mpi?
>> 
>> Thanks
>> 
>> MM
> 
> 
> Hi MM,
> 
> you can just provide your own function object to the boost::mpi::reduce function
> 
> Matthias
> 
> 
> _______________________________________________
> Boost-mpi mailing list
> Boost-mpi_at_[hidden]
> http://lists.boost.org/mailman/listinfo.cgi/boost-mpi
> 
> 
> _______________________________________________
> Boost-mpi mailing list
> Boost-mpi_at_[hidden]
> http://lists.boost.org/mailman/listinfo.cgi/boost-mpi