int PassTokenComm(const MPI_Comm comm, int *send_message, int *recv_message ) {
int rank, size;
MPI_Comm_rank (comm, &rank);
MPI_Comm_size (comm, &size);
int tag = 0;
MPI_Status status;
int retval;
int recv_neigh = (rank - 1 < 0) ? size - 1 : rank - 1;
int send_neigh = (rank + 1) % size;
if (rank == 0) {
if ((retval = MPI_Send(send_message, 1, MPI_INT, send_neigh, tag, comm)) != MPI_SUCCESS)
mpi_error(retval);
if ((retval = MPI_Recv(recv_message, 1, MPI_INT, recv_neigh, tag, comm, &status)) != MPI_SUCCESS)
mpi_error(retval);
} else {
if ((retval = MPI_Recv(recv_message, 1, MPI_INT, recv_neigh, tag, comm, &status)) != MPI_SUCCESS)
mpi_error(retval);
if ((retval = MPI_Send(send_message, 1, MPI_INT, send_neigh, tag, comm)) != MPI_SUCCESS)
mpi_error(retval);
}
//printf("Node %d recieved message from Node %d: %d\n", rank, recv_neigh, recieved_message);
return 0;
}
int MPI_Send( void *buf,
int count,
MPI_Datatype datatype,
int dest,
int tag,
MPI_Comm comm )
{
mpi_error();
return( MPI_ERR_OTHER );
}
/* m - number of rows of processors
n - number of columns of processors
m*n = total number of processors
*/
int CreateGemmCommGroups(const int m, const int n, const MPI_Comm comm, MPI_Comm *comm_row, MPI_Comm *comm_col) {
int retval;
int rank, size;
MPI_Comm_rank (comm, &rank);
MPI_Comm_size (comm, &size);
assert(size == m*n);
// Create row communication group
if ((retval = MPI_Comm_split(comm, rank % m, rank / m, comm_row)) != MPI_SUCCESS)
mpi_error(retval);
// Create column communication group
if ((retval = MPI_Comm_split(comm, rank / m, rank % m, comm_col)) != MPI_SUCCESS)
mpi_error(retval);
return 0;
}
int MPI_Recv( void *buf,
int count,
MPI_Datatype datatype,
int source,
int tag,
MPI_Comm comm,
MPI_Status *status )
{
mpi_error();
return( MPI_ERR_OTHER );
}
int MPI_Irecv( void *buf,
int count,
MPI_Datatype datatype,
int source,
int tag,
MPI_Comm comm,
MPI_Request *request )
{
mpi_error();
return( MPI_ERR_OTHER );
}
int MPI_Wait( MPI_Request *request,
MPI_Status *status )
{
mpi_error();
return( MPI_ERR_OTHER );
}
int ShiftMPIMatrixLeft(MPI_Comm comm_row, int gm, int gn, int bm, int bn, int p, int q, double *a) {
int rank, size;
MPI_Comm_rank (comm_row, &rank);
MPI_Comm_size (comm_row, &size);
int tag = 0;
MPI_Status status;
int retval;
int recv_neigh = (rank + 1) % size;
int send_neigh = (rank - 1 < 0) ? size - 1 : rank - 1;
double *a_buffer = malloc(sizeof(double) * (gm*gn) / (p*q));
if (a_buffer == NULL) {
fprintf(stderr, "Failed to malloc memory for arrays\n");
exit(1);
}
int
pm = bm / p,
pn = bn / q;
int
m = gm / bm,
n = gn / bn;
int a_offset;
int a_buffer_offset;
int message_size = (pm*pn);
int bi, bj;
if (rank == 0) {
for ( bi=0; bi<m; bi++ )
for ( bj=0; bj<n; bj++ ) {
a_offset = (bi + bj * m) * (pm*pn);
if ((retval = MPI_Send(a + a_offset, message_size, MPI_DOUBLE, send_neigh, tag, comm_row)) != MPI_SUCCESS)
mpi_error(retval);
}
for ( bi=0; bi<m; bi++ )
for ( bj=0; bj<n; bj++ ) {
a_buffer_offset = (bi + bj * m) * (pm*pn);
if ((retval = MPI_Recv(a_buffer + a_buffer_offset, message_size, MPI_DOUBLE, recv_neigh, tag, comm_row, &status)) != MPI_SUCCESS)
mpi_error(retval);
}
} else {
for ( bi=0; bi<m; bi++ )
for ( bj=0; bj<n; bj++ ) {
if (recv_neigh == 0) {
a_buffer_offset = (bi + (bj == 0 ? n-1 : bj-1) * m) * (pm*pn);
} else {
a_buffer_offset = (bi + bj * m) * (pm*pn);
}
if ((retval = MPI_Recv(a_buffer + a_buffer_offset, message_size, MPI_DOUBLE, recv_neigh, tag, comm_row, &status)) != MPI_SUCCESS)
mpi_error(retval);
}
for ( bi=0; bi<m; bi++ )
for ( bj=0; bj<n; bj++ ) {
a_offset = (bi + bj * m) * (pm*pn);
if ((retval = MPI_Send(a + a_offset, message_size, MPI_DOUBLE, send_neigh, tag, comm_row)) != MPI_SUCCESS)
mpi_error(retval);
}
}
// Copy data from buffer to Matrix
int i;
for ( i=0; i<(gm*gn) / (p*q); i++ )
a[i] = a_buffer[i];
free(a_buffer);
return 0;
}