On 7 September 2010 17:08, Allen Zhao <a.z...@gtisoft.com> wrote: > Hi, All, > > A newbie question: > > Suppose that I have a main executable (a non-MPI code, which just > dynamically loaded a named share library), and I do compile the shared > library with mpi-gcc. This way, when the main executable loads the shared > library, what is going to happen? >
Should work just fine. This is the way I use many MPI-based libs and MPI itself from Python. However, make sure you dlopen() libmpi.so with mode RTLD_GLOBAL, or things can co bad (this is the case with OpenMPI). > Can I parallel this application without calling MPI_Init() inside the main > code, instead, I call MPI_Init() when the shared library is loaded by the > main executable? Of course. > Will it then be able to run in parallel? Unlikely. But you could use MPI_Comm_spawn() to spawn a new application, then your main sequential code "chats" to the child parallel app using MPI calls. > If this scenario > is possible, when should I call MPI_Finalize()? > When you know you will not use MPI any more. Perhaps you could register a finalizer using atexit()... -- Lisandro Dalcin --------------- CIMEC (INTEC/CONICET-UNL) Predio CONICET-Santa Fe Colectora RN 168 Km 472, Paraje El Pozo Tel: +54-342-4511594 (ext 1011) Tel/Fax: +54-342-4511169
