Re: [Boost-users] mpi non-blocking communication

Subject: Re: [Boost-users] mpi non-blocking communication
From: Hicham Mouline (hicham_at_[hidden])
Date: 2010-12-06 05:58:08

> (1) You must initialize MPI with MPI_Init_thread() instead of 
>MPI_Init().  The boost::mpi::communicator ctor uses MPI_Init(), so you 
>must run the initialization yourself and *then* create the 
>communicator object. Â For instance::Â 
>Â  Â  Â  MPI_Init_thread(&argc, &argv, MPI_THREAD_SERIALIZED)Â 
>      // ... 
>Â  Â  Â  mpi::communicator world;Â 

Riccardo,

I have the following code in my main: 

int main(int argc, char* argv[])
{
  boost::mpi::environment env(argc, argv);
  const int mpi_thread_support = MPI::Init_thread(argc, argv, MPI_THREAD_SERIALIZED );
  if (mpi_thread_support != MPI_THREAD_SERIALIZED)
  {
    std::cerr<< "MPI implementation does not support threads" <<std::endl;
    return 1;
  }
  boost::mpi::communicator world;
...
}

This prints an error however:

Calling MPI_Init or MPI_Init_thread twice is erroneous.

How does 1 avoid that the mpi::communicator constructor calling MPI_INIT twice?

Perhaps it's the environment constructor that calls MPI_INIT?

rds,