#include <stdio.h>
/* Prototypes for picky compilers */
-void SetData ( double *, double *, int, int, int, int, int, int );
-int CheckData ( double *, int, int, int, int, int, int );
+void SetData(double *, double *, int, int, int, int, int, int);
+int CheckData(double *, int, int, int, int, int, int);
/*
This is an example of using scatterv to send a matrix from one
process to all others, with the matrix stored in Fortran order.
*/
-void SetData( double *sendbuf, double *recvbuf, int nx, int ny,
- int myrow, int mycol, int nrow, int ncol )
+void SetData(double *sendbuf, double *recvbuf, int nx, int ny,
+ int myrow, int mycol, int nrow, int ncol)
{
int coldim, i, j, m, k;
double *p;
if (myrow == 0 && mycol == 0) {
coldim = nx * nrow;
- for (j=0; j<ncol; j++) {
- for (i=0; i<nrow; i++) {
+ for (j = 0; j < ncol; j++) {
+ for (i = 0; i < nrow; i++) {
p = sendbuf + i * nx + j * (ny * coldim);
- for (m=0; m<ny; m++) {
- for (k=0; k<nx; k++) {
+ for (m = 0; m < ny; m++) {
+ for (k = 0; k < nx; k++) {
p[k] = 1000 * j + 100 * i + m * nx + k;
}
p += coldim;
}
}
}
- for (i=0; i<nx*ny; i++)
+ for (i = 0; i < nx * ny; i++)
recvbuf[i] = -1.0;
}
-int CheckData( double *recvbuf,
- int nx, int ny, int myrow, int mycol, int nrow,
- int expect_no_value )
+int CheckData(double *recvbuf, int nx, int ny, int myrow, int mycol, int nrow, int expect_no_value)
{
int coldim, m, k;
double *p, val;
int errs = 0;
coldim = nx;
- p = recvbuf;
- for (m=0; m<ny; m++) {
- for (k=0; k<nx; k++) {
+ p = recvbuf;
+ for (m = 0; m < ny; m++) {
+ for (k = 0; k < nx; k++) {
/* If expect_no_value is true then we assume that the pre-scatterv
* value should remain in the recvbuf for our portion of the array.
* This is the case for the root process when using MPI_IN_PLACE. */
errs++;
if (errs < 10) {
printf("Error in (%d,%d) [%d,%d] location, got %f expected %f\n",
- m, k, myrow, mycol, p[k], val );
+ m, k, myrow, mycol, p[k], val);
}
else if (errs == 10) {
- printf( "Too many errors; suppressing printing\n" );
+ printf("Too many errors; suppressing printing\n");
}
}
}
return errs;
}
-int main( int argc, char **argv )
+int main(int argc, char **argv)
{
int rank, size, myrow, mycol, nx, ny, stride, cnt, i, j, errs, errs_in_place, tot_errs;
- double *sendbuf, *recvbuf;
+ double *sendbuf, *recvbuf;
MPI_Datatype vec, block, types[2];
MPI_Aint displs[2];
- int *scdispls;
- int blens[2];
+ int *scdispls;
+ int blens[2];
MPI_Comm comm2d;
int dims[2], periods[2], coords[2], lcoords[2];
int *sendcounts;
- MPI_Init( &argc, &argv );
- MPI_Comm_rank( MPI_COMM_WORLD, &rank );
- MPI_Comm_size( MPI_COMM_WORLD, &size );
+ MPI_Init(&argc, &argv);
+ MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+ MPI_Comm_size(MPI_COMM_WORLD, &size);
/* Get a 2-d decomposition of the processes */
- dims[0] = 0; dims[1] = 0;
- MPI_Dims_create( size, 2, dims );
- periods[0] = 0; periods[1] = 0;
- MPI_Cart_create( MPI_COMM_WORLD, 2, dims, periods, 0, &comm2d );
- MPI_Cart_get( comm2d, 2, dims, periods, coords );
+ dims[0] = 0;
+ dims[1] = 0;
+ MPI_Dims_create(size, 2, dims);
+ periods[0] = 0;
+ periods[1] = 0;
+ MPI_Cart_create(MPI_COMM_WORLD, 2, dims, periods, 0, &comm2d);
+ MPI_Cart_get(comm2d, 2, dims, periods, coords);
myrow = coords[0];
mycol = coords[1];
/*
if (rank == 0)
- printf( "Decomposition is [%d x %d]\n", dims[0], dims[1] );
+ printf("Decomposition is [%d x %d]\n", dims[0], dims[1]);
*/
/* Get the size of the matrix */
ny = 8;
stride = nx * dims[0];
- recvbuf = (double *)malloc( nx * ny * sizeof(double) );
+ recvbuf = (double *) malloc(nx * ny * sizeof(double));
if (!recvbuf) {
- MPI_Abort( MPI_COMM_WORLD, 1 );
- exit(1);
+ MPI_Abort(MPI_COMM_WORLD, 1);
}
sendbuf = 0;
if (myrow == 0 && mycol == 0) {
- sendbuf = (double *)malloc( nx * ny * size * sizeof(double) );
+ sendbuf = (double *) malloc(nx * ny * size * sizeof(double));
if (!sendbuf) {
- MPI_Abort( MPI_COMM_WORLD, 1 );
- exit(1);
+ MPI_Abort(MPI_COMM_WORLD, 1);
}
}
- sendcounts = (int *) malloc( size * sizeof(int) );
- scdispls = (int *)malloc( size * sizeof(int) );
+ sendcounts = (int *) malloc(size * sizeof(int));
+ scdispls = (int *) malloc(size * sizeof(int));
- MPI_Type_vector( ny, nx, stride, MPI_DOUBLE, &vec );
- blens[0] = 1; blens[1] = 1;
- types[0] = vec; types[1] = MPI_UB;
- displs[0] = 0; displs[1] = nx * sizeof(double);
+ MPI_Type_vector(ny, nx, stride, MPI_DOUBLE, &vec);
+ blens[0] = 1;
+ blens[1] = 1;
+ types[0] = vec;
+ types[1] = MPI_UB;
+ displs[0] = 0;
+ displs[1] = nx * sizeof(double);
- MPI_Type_struct( 2, blens, displs, types, &block );
- MPI_Type_free( &vec );
- MPI_Type_commit( &block );
+ MPI_Type_struct(2, blens, displs, types, &block);
+ MPI_Type_free(&vec);
+ MPI_Type_commit(&block);
/* Set up the transfer */
- cnt = 0;
- for (i=0; i<dims[1]; i++) {
- for (j=0; j<dims[0]; j++) {
+ cnt = 0;
+ for (i = 0; i < dims[1]; i++) {
+ for (j = 0; j < dims[0]; j++) {
sendcounts[cnt] = 1;
/* Using Cart_coords makes sure that ranks (used by
- sendrecv) matches the cartesian coordinates (used to
- set data in the matrix) */
- MPI_Cart_coords( comm2d, cnt, 2, lcoords );
+ * sendrecv) matches the cartesian coordinates (used to
+ * set data in the matrix) */
+ MPI_Cart_coords(comm2d, cnt, 2, lcoords);
scdispls[cnt++] = lcoords[0] + lcoords[1] * (dims[0] * ny);
}
}
- SetData( sendbuf, recvbuf, nx, ny, myrow, mycol, dims[0], dims[1] );
- MPI_Scatterv( sendbuf, sendcounts, scdispls, block,
- recvbuf, nx * ny, MPI_DOUBLE, 0, comm2d );
- if((errs = CheckData( recvbuf, nx, ny, myrow, mycol, dims[0], 0 ))) {
- fprintf( stdout, "Failed to transfer data\n" );
+ SetData(sendbuf, recvbuf, nx, ny, myrow, mycol, dims[0], dims[1]);
+ MPI_Scatterv(sendbuf, sendcounts, scdispls, block, recvbuf, nx * ny, MPI_DOUBLE, 0, comm2d);
+ if ((errs = CheckData(recvbuf, nx, ny, myrow, mycol, dims[0], 0))) {
+ fprintf(stdout, "Failed to transfer data\n");
}
/* once more, but this time passing MPI_IN_PLACE for the root */
- SetData( sendbuf, recvbuf, nx, ny, myrow, mycol, dims[0], dims[1] );
- MPI_Scatterv( sendbuf, sendcounts, scdispls, block,
- (rank == 0 ? MPI_IN_PLACE : recvbuf), nx * ny, MPI_DOUBLE, 0, comm2d );
- errs_in_place = CheckData( recvbuf, nx, ny, myrow, mycol, dims[0], (rank == 0) );
- if(errs_in_place) {
- fprintf( stdout, "Failed to transfer data (MPI_IN_PLACE)\n" );
+ SetData(sendbuf, recvbuf, nx, ny, myrow, mycol, dims[0], dims[1]);
+ MPI_Scatterv(sendbuf, sendcounts, scdispls, block,
+ (rank == 0 ? MPI_IN_PLACE : recvbuf), nx * ny, MPI_DOUBLE, 0, comm2d);
+ errs_in_place = CheckData(recvbuf, nx, ny, myrow, mycol, dims[0], (rank == 0));
+ if (errs_in_place) {
+ fprintf(stdout, "Failed to transfer data (MPI_IN_PLACE)\n");
}
errs += errs_in_place;
- MPI_Allreduce( &errs, &tot_errs, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD );
+ MPI_Allreduce(&errs, &tot_errs, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD);
if (rank == 0) {
if (tot_errs == 0)
- printf( " No Errors\n" );
+ printf(" No Errors\n");
else
- printf( "%d errors in use of MPI_SCATTERV\n", tot_errs );
+ printf("%d errors in use of MPI_SCATTERV\n", tot_errs);
}
- if (sendbuf) free( sendbuf );
- free( recvbuf );
- free( sendcounts );
- free( scdispls );
- MPI_Type_free( &block );
- MPI_Comm_free( &comm2d );
+ if (sendbuf)
+ free(sendbuf);
+ free(recvbuf);
+ free(sendcounts);
+ free(scdispls);
+ MPI_Type_free(&block);
+ MPI_Comm_free(&comm2d);
MPI_Finalize();
return errs;
}
-
-
