Re: [Boost-users] mpi all_reduce

On 2010-12-02 23:37:34 +0100, Riccardo Murri said:

Hi Phillip,

On Thu, Dec 2, 2010 at 7:08 PM, Kraus Philipp <philipp.kraus@flashpixx.de> wrote:

...

how can I use the mpi::all_reduce with std::accumulate? I would reduce the values of each process with a sum function

You can use mpi::all_reduce like this::

int local_value = ...; // local computation int global_value = 0; mpi::all_reduce(comm_, local_value, global_value, std::plus<int>()); // now `global_value` holds the sum of `local_value` of all MPI ranks

where `comm_` is an instance of mpi::communicator; other binary operations are available besides std::plus (or you can define your own).

Thank's Phil