Hi all,
I need you help in self-defined datatype. I have written the following
code
#include <mpi.h>
#include <stdio.h>
#define FIVE
#define NCOLS 4
#define NROWS 4
#ifdef FIVE
typedef struct
{
double r, c, d, v, f;
} Grid;
#else
typedef struct
{
double r, c, v, d;
} Grid;
#endif
Grid data[NROWS][NCOLS];
int myrank, NODENUM;
int SIZE;
MPI_Datatype GRID;
MPI_Datatype ROW;
void initialize(int argc, char **argv)
{ int errcode, i, j;
#ifndef FIVE
int S=4;
MPI_Datatype type[4] = { MPI_DOUBLE, MPI_DOUBLE, MPI_DOUBLE,
MPI_DOUBLE};
int blocklen[4] = { 1, 1, 1, 1 };
MPI_Aint disp[4] = { 0, sizeof(double), sizeof(double),
sizeof(double)};
#else
int S=5;
MPI_Datatype type[5] = { MPI_DOUBLE, MPI_DOUBLE, MPI_DOUBLE,
MPI_DOUBLE, MPI_DOUBLE};
int blocklen[5] = { 1, 1, 1, 1, 1 };
MPI_Aint disp[5] = { 0, sizeof(double), sizeof(double),
sizeof(double), sizeof(double)};
#endif
errcode = MPI_Init(&argc, &argv);
if (errcode == MPI_SUCCESS)
{
MPI_Comm_rank( MPI_COMM_WORLD, &myrank );
MPI_Comm_size( MPI_COMM_WORLD, &NODENUM );
SIZE = NROWS/NODENUM;
MPI_Type_struct( S, blocklen, disp, type, &GRID );
MPI_Type_commit( &GRID );
MPI_Type_vector( NCOLS, 1, 1, GRID, &ROW );
MPI_Type_commit( &ROW );
for (i=0; i<NROWS; i++)
{
for (j=0; j<NCOLS; j++)
{
data[i][j].r = (double)(i+1);
data[i][j].c = (double)(j+1);
data[i][j].d = 1.0;
data[i][j].v = (double)(i*NCOLS + j + 1);
#ifdef FIVE
data[i][j].f = 2.0;
#endif
}
}
}
}
void finalize(void)
{
MPI_Type_free(&GRID);
MPI_Type_free(&ROW);
MPI_Finalize();
}
int main(int argc, char *argv[])
{
initialize(argc, argv);
MPI_Barrier( MPI_COMM_WORLD );
/* show data here */
if (myrank==0)
{
MPI_Send( &data[0][0], 1, ROW, 1, 22, MPI_COMM_WORLD );
}
else MPI_Recv( &data[SIZE][0], 1, ROW, 0, 22, MPI_COMM_WORLD,
MPI_STATUS_IGNORE );
MPI_Barrier( MPI_COMM_WORLD );
/* show data here */
finalize();
return 0;
}
The program is running over two computers. At the beginning, each
computer holds all the data stored in 'data' array. I am going to define
a new datatype for a row and send the first row of the array from node 0
to node 1. However, the result is not that I wanted. I print the whole
array at node 1
The original array is
1 2 3 4
5 6 7 8
9 10 11 12
13 14 15 16
if macro 'FIVE' is defined, i.e. five data defined in the struct, I got
1 2 3 4
5 6 7 8
1 10 11 12
13 14 15 16
if macro 'FIVE' is undefine, i.e. only four data defined in the struct,
I got
1 2 3 4
5 6 7 8
1 2 11 12
13 14 15 16
But I an intending to get
1 2 3 4
5 6 7 8
1 2 3 4 <----- a row received from the first row on node 0
13 14 15 16
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