Lockless Inc

NAME

MPI_Startall - Starts an array of persistent requests

SYNOPSIS

#include <mpi.h> int MPI_Startall(int count , MPI_Request *rq );

#include <pmpi.h> int PMPI_Startall(int count , MPI_Request *rq );

#include <mpi.h> static void MPI::Prequest::Startall(int count , MPI::Prequest *rq );

INCLUDE 'mpif.h' MPI_STARTALL(count , rq , ierr ) INTEGER count , rq (*), ierr

INPUT PARAMETERS

count - size of array (integer)

rq - array of persistent requests (array of handles)

DESCRIPTION

The MPI_Startall() function is used to start several persistent requests. These requests in the array, rq of size count , must be in a completed (or initialized) state. Once started, the requests will transition into an "active" state until completed via a call to a function similar to MPI_Wait().

The advantage of using requests is that most error-checking is done only once, when they are initially created. This may cut down on overhead, and improve performance.

When persistent requests are no longer needed, they should be freed with MPI_Request_free().

PMPI_Startall() is the profiling version of this function.

ERRORS

All MPI routines except for MPI_Wtime and MPI_Wtick return an error code. The the current MPI error handler is invoked if the return value is not MPI_SUCCESS. The default error handler aborts, but this may be changed with by using the MPI_Errhandler_set() function. The predefined error handler MPI_ERRORS_RETURN may be used to cause error values to be returned instead. Note that MPI does not guarentee that an MPI program can continue past an error. In this implementation, all errors except MPI_ERR_INTERN or MPI_ERR_OTHER should always be recoverable.

In C, the error code is passed as the return value. In FORTRAN, all functions have an parameter ierr which returns the error code. MPI C++ functions do not directly return an error code. However, C++ users may want to use the MPI::ERRORS_THROW_EXCEPTIONS handler. This will throw an MPI::Exception with the corresponding error code. To prevent exceptions from being raised from within C and Fortran code, they will see all error return values as MPI_ERR_PENDING when this handler is chosen. In this implementation, call MPI::throw_exception() to throw the correct exception if this occurs.

MPI_SUCCESS - No error;

MPI_ERR_PENDING - Pending exception;

MPI_ERR_COUNT - Invalid array size;

MPI_ERR_REQUEST - Invalid request;

MPI_ERR_INTERN - Out of Memory.

SEE ALSO

MPI_Start (3) MPI_Wait (3) MPI_Send_init (3) MPI_Bsend_init (3) MPI_Rsend_init (3) MPI_Ssend_init (3) MPI_Recv_init (3) MPI_Request_free (3)

About Us Returns Policy Privacy Policy Send us Feedback
Company Info | Product Index | Category Index | Help | Terms of Use
Copyright © Lockless Inc All Rights Reserved.