/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */
/*
 *
 *  (C) 2003 by Argonne National Laboratory.
 *      See COPYRIGHT in top-level directory.
 */
#include "mpi.h"
#include <stdio.h>
#include <stdlib.h>
#include "mpitest.h"

#ifndef MAX_INT
#define MAX_INT 0x7fffffff
#endif

/*
static char MTEST_Descrip[] = "Test MPI_Accumulate with fence";
*/

int main( int argc, char *argv[] )
{
    int errs = 0;
    int rank, size, source, dest;
    int minsize = 2, count, i; 
    MPI_Comm      comm;
    MPI_Win       win;
    MPI_Datatype  datatype;
    int           *winbuf, *sbuf;

    MTest_Init( &argc, &argv );

    /* The following illustrates the use of the routines to 
       run through a selection of communicators and datatypes.
       Use subsets of these for tests that do not involve combinations 
       of communicators, datatypes, and counts of datatypes */
    while (MTestGetIntracommGeneral( &comm, minsize, 1 )) {
	if (comm == MPI_COMM_NULL) continue;
	/* Determine the sender and receiver */
	MPI_Comm_rank( comm, &rank );
	MPI_Comm_size( comm, &size );
	source = 0;
	dest   = size - 1;
	
	for (count = 1; count < 65000; count = count * 2) {
	    datatype = MPI_INT;
	    /* We compare with an integer value that can be as large as
	       size * (count * count + (1/2)*(size-1))
	       For large machines (size large), this can exceed the 
	       maximum integer for some large values of count.  We check
	       that in advance and break this loop if the above value 
	       would exceed MAX_INT.  Specifically,

	       size*count*count + (1/2)*size*(size-1) > MAX_INT
	       count*count > (MAX_INT/size - (1/2)*(size-1))
	    */
	    if (count * count > (MAX_INT/size - (size-1)/2)) break;
	    winbuf = (int *)malloc( count * sizeof(int) );
	    sbuf   = (int *)malloc( count * sizeof(int) );

	    for (i=0; i<count; i++) winbuf[i] = 0;
	    for (i=0; i<count; i++) sbuf[i] = rank + i * count;
	    MPI_Win_create( winbuf, count * sizeof(int), sizeof(int),
			    MPI_INFO_NULL, comm, &win );
	    MPI_Win_fence( 0, win );
	    MPI_Accumulate( sbuf, count, MPI_INT, source, 0, count, MPI_INT,
				MPI_SUM, win );
	    MPI_Win_fence( 0, win );
	    if (rank == source) {
		/* Check the results */
		for (i=0; i<count; i++) {
		    int result = i * count * size + (size*(size-1))/2;
		    if (winbuf[i] != result) {
			if (errs < 10) {
			    fprintf( stderr, "Winbuf[%d] = %d, expected %d (count = %d, size = %d)\n",
				     i, winbuf[i], result, count, size );
			}
			errs++;
		    }
		}
	    }
	    free( winbuf );
	    free( sbuf );
	    MPI_Win_free( &win );
	}
        MTestFreeComm(&comm);
    }

    MTest_Finalize( errs );
    MPI_Finalize();
    return 0;
}
