Thread: MPI in C

Hi all

I am using MPI and c programming. i want to collect strings from processors to root processor
now i have writen the code as below but does not display the strings. Can anyone help me with this?
The code is as below:

Code:

#include <mpi.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
int main(int argc, char *argv[]){
int numProcs;
int myRank, a, *data, i;
char **DATA;
char *b;
//initialize MPI
MPI_Init(&argc, &argv);
MPI_Comm_rank(MPI_COMM_WORLD,&myRank);
MPI_Comm_size(MPI_COMM_WORLD, &numProcs);
// do some computation and MPI communications
a = 1000+myRank;
 b = "sdfsd";
if (myRank == 1){
data = (int *) malloc(numProcs*sizeof(int));
DATA = (char **) calloc(numProcs, sizeof(char **));
for (i=0;i<numProcs;i++){
data[i] = 0;
DATA[i] = "helloP";
 }
printf("\n contents of data array before gather:\n");
for (i=0;i<numProcs;i++)
printf("%s\n", DATA[i]);

}

MPI_Gather(&b, 5, MPI_CHAR, DATA, 5,  MPI_CHAR,1, MPI_COMM_WORLD);

printf("here are contents %s\n",DATA[1]); 
if (myRank == 1){
printf("\n contents of data array after gather:\n");
for (i=0;i<numProcs;i++){
	printf("%s\n", DATA[i]);
 /*printf("2. DATA[%d] = %s \n",i, DATA[i]);*/}}

//shutdown MPI
MPI_Finalize();
return 0;
}

Thanks matsp for quick response. Actually bellow is the message i receive:

rank 2 in job 8 cslab117-002_50788 caused collective abort of all ranks
exit status of rank 2: killed by signal 11
rank 0 in job 8 cslab117-002_50788 caused collective abort of all ranks
exit status of rank 0: killed by signal 11

well, when i remove the line

Code:

 DATA[i] = "helloP";

i still get the message:
rank 1 in job 11 cslab117-002_50788 caused collective abort of all ranks
exit status of rank 1: killed by signal 11
Clear allocation of memory is not a problem here. so im wondering exactly what i need to change. If you look at line:

Code:

 MPI_Gather(&b, 5, MPI_CHAR, DATA, 5,  MPI_CHAR,1, MPI_COMM_WORLD);

, can you pick something that might be causing this error, because i suspect that the error is there