/* -*- 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 "mpitestconf.h"

#ifdef HAVE_IOSTREAM

// Not all C++ compilers have iostream instead of iostream.h

#include <iostream>

#ifdef HAVE_NAMESPACE_STD

// Those that do often need the std namespace; otherwise, a bare "cout"

// is likely to fail to compile

using namespace std;

#endif

#else

#include <iostream.h>

#endif

#include "mpitestcxx.h"

#include <assert.h>

static char MTEST_Descrip[] = "Test MPI_Allreduce with non-commutative user-defined operations";

/* We make the error count global so that we can easily control the output

   of error information (in particular, limiting it after the first 10

   errors */

int errs = 0;

/* This implements a simple matrix-matrix multiply.  This is an associative

   but not commutative operation.  The matrix size is set in matSize;

   the number of matrices is the count argument. The matrix is stored

   in C order, so that

     c(i,j) is cin[j+i*matSize]

 */

#define MAXCOL 256

static int matSize = 0;         /* Must be < MAXCOL */

static int max_offset = 0;

void uop(const void *cinPtr, void *coutPtr, int count, const MPI::Datatype & dtype)

{

    const int *cin = (const int *) cinPtr;

    int *cout = (int *) coutPtr;

    int i, j, k, nmat;

    int tempcol[MAXCOL];

    int offset1, offset2;

    int matsize2 = matSize * matSize;

    for (nmat = 0; nmat < count; nmat++) {

        for (j = 0; j < matSize; j++) {

            for (i = 0; i < matSize; i++) {

                tempcol[i] = 0;

                for (k = 0; k < matSize; k++) {

                    /* col[i] += cin(i,k) * cout(k,j) */

                    offset1 = k + i * matSize;

                    offset2 = j + k * matSize;

                    assert(offset1 < max_offset);

                    assert(offset2 < max_offset);

                    tempcol[i] += cin[offset1] * cout[offset2];

                }

            }

            for (i = 0; i < matSize; i++) {

                offset1 = j + i * matSize;

                assert(offset1 < max_offset);

                cout[offset1] = tempcol[i];

            }

        }

        cin += matsize2;

        cout += matsize2;

    }

}

/* Initialize the integer matrix as a permutation of rank with rank+1.

   If we call this matrix P_r, we know that product of P_0 P_1 ... P_{size-2}

   is the the matrix representing the permutation that shifts left by one.

   As the final matrix (in the size-1 position), we use the matrix that

   shifts RIGHT by one

*/

static void initMat(MPI::Intracomm comm, int mat[])

{

    int i, j, size, rank;

    int offset;

    rank = comm.Get_rank();

    size = comm.Get_size();

    for (i = 0; i < size * size; i++) {

        assert(i < max_offset);

        mat[i] = 0;

    }

    if (rank < size - 1) {

        /* Create the permutation matrix that exchanges r with r+1 */

        for (i = 0; i < size; i++) {

            if (i == rank) {

                offset = ((i + 1) % size) + i * size;

                assert(offset < max_offset);

                mat[offset] = 1;

            } else if (i == ((rank + 1) % size)) {

                offset = ((i + size - 1) % size) + i * size;

                assert(offset < max_offset);

                mat[offset] = 1;

            } else {

                offset = i + i * size;

                assert(offset < max_offset);

                mat[offset] = 1;

            }

        }

    } else {

        /* Create the permutation matrix that shifts right by one */

        for (i = 0; i < size; i++) {

            for (j = 0; j < size; j++) {

                offset = j + i * size;  /* location of c(i,j) */

                mat[offset] = 0;

                if (((j - i + size) % size) == 1)

                    mat[offset] = 1;

            }

        }

    }

}

/* Compare a matrix with the identity matrix */

static int isIdentity(MPI::Intracomm comm, int mat[])

{

    int i, j, size, rank, lerrs = 0;

    int offset;

    rank = comm.Get_rank();

    size = comm.Get_size();

    for (i = 0; i < size; i++) {

        for (j = 0; j < size; j++) {

            if (i == j) {

                offset = j + i * size;

                assert(offset < max_offset);

                if (mat[offset] != 1) {

                    lerrs++;

                    if (errs + lerrs < 10) {

                        cerr << "[" << rank << "] mat[" << i << "," << j << "] = " << mat[offset] <<

                            ", expected 1 for comm " << MTestGetIntracommName() << endl;

                    }

                }

            } else {

                offset = j + i * size;

                assert(offset < max_offset);

                if (mat[offset] != 0) {

                    lerrs++;

                    if (errs + lerrs < 10) {

                        cerr << "[" << rank << "] mat[" << i << "," << j << "] = " << mat[offset] <<

                            ", expected 0 for comm " << MTestGetIntracommName() << endl;

                    }

                }

            }

        }

    }

    return lerrs;

}

int main(int argc, char *argv[])

{

    int size;

    int minsize = 2, count;

    MPI::Intracomm comm;

    int *buf, *bufout;

    MPI::Op op;

    MPI::Datatype mattype;

    MTest_Init();

    op.Init(uop, false);

    while (MTestGetIntracommGeneral(comm, minsize, 1)) {

        if ((MPI::Intracomm) comm == (MPI::Intracomm) MPI_COMM_NULL) {

            continue;

        }

        size = comm.Get_size();

        matSize = size;

        /* Only one matrix for now */

        count = 1;

        /* A single matrix, the size of the communicator */

        mattype = MPI::INT.Create_contiguous(size * size);

        mattype.Commit();

        max_offset = count * size * size;

        buf = new int[max_offset];

        if (!buf) {

            MPI::COMM_WORLD.Abort(1);

        }

        bufout = new int[max_offset];

        if (!bufout) {

            MPI::COMM_WORLD.Abort(1);

        }

        initMat(comm, buf);

        comm.Allreduce(buf, bufout, count, mattype, op);

        errs += isIdentity(comm, bufout);

        /* Try the same test, but using MPI_IN_PLACE */

        initMat(comm, bufout);

        comm.Allreduce(MPI_IN_PLACE, bufout, count, mattype, op);

        errs += isIdentity(comm, bufout);

        delete[]buf;

        delete[]bufout;

        mattype.Free();

        MTestFreeComm(comm);

    }

    op.Free();

    MTest_Finalize(errs);

    return 0;

}