get_count.c

mpi并行计算的c++代码 可用vc或gcc编译通过 可以用来搭建并行计算试验环境

/* -*- Mode: C; c-basic-offset:4 ; -*- */
/*  $Id: get_count.c,v 1.7 2005/11/01 20:32:01 rross Exp $
 *
 *  (C) 2001 by Argonne National Laboratory.
 *      See COPYRIGHT in top-level directory.
 */

#include "mpiimpl.h"

/* -- Begin Profiling Symbol Block for routine MPI_Get_count */
#if defined(HAVE_PRAGMA_WEAK)
#pragma weak MPI_Get_count = PMPI_Get_count
#elif defined(HAVE_PRAGMA_HP_SEC_DEF)
#pragma _HP_SECONDARY_DEF PMPI_Get_count  MPI_Get_count
#elif defined(HAVE_PRAGMA_CRI_DUP)
#pragma _CRI duplicate MPI_Get_count as PMPI_Get_count
#endif
/* -- End Profiling Symbol Block */

/* Define MPICH_MPI_FROM_PMPI if weak symbols are not supported to build
   the MPI routines */
#ifndef MPICH_MPI_FROM_PMPI
#define MPI_Get_count PMPI_Get_count
#endif

#undef FUNCNAME
#define FUNCNAME MPI_Get_count

/*@
  MPI_Get_count - Gets the number of "top level" elements

Input Parameters:
+ status - return status of receive operation (Status) 
- datatype - datatype of each receive buffer element (handle) 

Output Parameter:
. count - number of received elements (integer) 
Notes:
If the size of the datatype is zero, this routine will return a count of
zero.  If the amount of data in 'status' is not an exact multiple of the 
size of 'datatype' (so that 'count' would not be integral), a 'count' of
'MPI_UNDEFINED' is returned instead.

.N fortran

.N Errors
.N MPI_SUCCESS
.N MPI_ERR_TYPE
@*/
int MPI_Get_count( MPI_Status *status, 	MPI_Datatype datatype, int *count )
{
    static const char FCNAME[] = "MPI_Get_count";
    int mpi_errno = MPI_SUCCESS;
    int size;
    MPID_MPI_STATE_DECL(MPID_STATE_MPI_GET_COUNT);

    MPIR_ERRTEST_INITIALIZED_ORDIE();
    
    MPID_CS_ENTER();
    MPID_MPI_FUNC_ENTER(MPID_STATE_MPI_GET_COUNT);

#   ifdef HAVE_ERROR_CHECKING
    {
        MPID_BEGIN_ERROR_CHECKS;
        {
	    MPID_Datatype *datatype_ptr = NULL;

	    MPIR_ERRTEST_ARGNULL(status, "status", mpi_errno);
	    MPIR_ERRTEST_ARGNULL(count, "count", mpi_errno);
	    MPIR_ERRTEST_DATATYPE(datatype, "datatype", mpi_errno);
            if (mpi_errno) goto fn_fail;

            /* Validate datatype_ptr */
	    if (HANDLE_GET_KIND(datatype) != HANDLE_KIND_BUILTIN) {
		MPID_Datatype_get_ptr(datatype, datatype_ptr);
		MPID_Datatype_valid_ptr(datatype_ptr, mpi_errno);
		/* Q: Must the type be committed to be used with this function? */
	    }
            if (mpi_errno) goto fn_fail;
        }
        MPID_END_ERROR_CHECKS;
    }
#   endif /* HAVE_ERROR_CHECKING */

    /* ... body of routine ...  */
    
    /* Check for correct number of bytes */
    MPID_Datatype_get_size_macro(datatype, size);
    if (size != 0) {
	if ((status->count % size) != 0)
	    (*count) = MPI_UNDEFINED;
	else
	    (*count) = status->count / size;
    }
    else {
	if (status->count > 0)
	{
	    /* --BEGIN ERROR HANDLING-- */

	    /* case where datatype size is 0 and count is > 0 should
	     * never occur.
	     */

	    (*count) = MPI_UNDEFINED;
	    /* --END ERROR HANDLING-- */
	}
	else {
	    /* This is ambiguous.  However, discussions on MPI Forum
	       reached a consensus that this is the correct return 
	       value
	    */
	    (*count) = 0;
	}
    }
    
    /* ... end of body of routine ... */

  fn_exit:
    MPID_MPI_FUNC_EXIT(MPID_STATE_MPI_GET_COUNT);
    MPID_CS_EXIT();
    return mpi_errno;
    
  fn_fail:
    /* --BEGIN ERROR HANDLING-- */
#   ifdef HAVE_ERROR_CHECKING
    {
	mpi_errno = MPIR_Err_create_code(
	    mpi_errno, MPIR_ERR_RECOVERABLE, FCNAME, __LINE__, MPI_ERR_OTHER, "**mpi_get_count",
	    "**mpi_get_count %p %D %p", status, datatype, count);
    }
#   endif
    mpi_errno = MPIR_Err_return_comm( 0, FCNAME, mpi_errno );
    goto fn_exit;
    /* --END ERROR HANDLING-- */
}