Hello,

I am not sure, if my code is correct according to Open MPI(v1.6). the code is given as follows, I am doing MPI one-sided communication inside a function - data_transfer. this function is being called inside a fence epoch. inside data_transfer, I am allocating memory for non-contiguous data, creating derived data type, using this datatype in MPI_Accumulate, and after calling MPI_Accumulate, freeing the indexed data type and also freeing the memory containing indices for indexed data type. is it okay that I am freeing memory for derived datatype before the closing fence?

I am getting segmentation fault with this code. if I comment out the MPI_Accumulate call, then no seg-fault occurs.

void data_transfer(void *data, int *sources_disp, int *targets_disp, int *target, int size, int *blength, int func, MPI_Op op, MPI_Win win, MPI_Datatype dtype){

int i,j, index;

int tmp_target;

int *flag;

int *source_disp;

int *target_disp;

MPI_Datatype source_type, target_type;

MPI_Alloc_mem( size*sizeof(int), MPI_INFO_NULL, &source_disp);

MPI_Alloc_mem( size*sizeof(int), MPI_INFO_NULL, &target_disp);

MPI_Alloc_mem( size*sizeof(int), MPI_INFO_NULL, &flag );

memset(flag, 0, size*sizeof(int));

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

if(flag[i]==0){

tmp_target = target[i];

index = 0;

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

if(flag[j]==0 && tmp_target == target[j] ){

source_disp[index] = sources_disp[j];

target_disp[index] = targets_disp[j];

//printf("src, target disp %d %d\n", j, disp[j]);

index++;

flag[j] = 1;

}

MPI_Type_indexed(index, blength , source_disp, dtype, &source_type);

MPI_Type_commit(&source_type);

MPI_Type_indexed(index, blength , target_disp, dtype, &target_type);

MPI_Type_commit(&target_type);

MPI_Accumulate( data, 1, source_type, tmp_target, 0, 1, target_type , op, win);

MPI_Type_free(&source_type);

MPI_Type_free(&target_type);

}

MPI_Free_mem(source_disp);

MPI_Free_mem(target_disp);

MPI_Free_mem(flag);

}

void main(){

int i;

while(i<N){

MPI_Win_fence(MPI_MODE_NOPRECEDE, queue2_win);

data_transfer();

MPI_Win_fence(MPI_MODE_NOSUCCEED, queue2_win);

}

}

thanks,
Ziaul