How do I define a global shared memory in LAM. I am having a problem
in running a program on more than 1 processor.
void indNodes(graph_t *G, int *vtxmap, MPI_Comm comm)
{
int *xadj, *adjncy, *deg, *checksum, *checksum1, *tmp;
int nvtx, u, v, i, istart, istop, j, jstart, jstop;
int my_rank, p, ivert, count, vstart, vend, size, ierr; //t, devide;
nvtx = G->nvtx;
xadj = G->xadj;
adjncy = G->adjncy;
MPI_Comm_rank(comm, &my_rank);
MPI_Comm_size(comm, &p);
/* -------------------------
set up the working arrays
------------------------- */
mymalloc(checksum, nvtx, int);
mymalloc(checksum1, nvtx, int);
/* -------------------------------------------------
compute for each vertex u its degree and checksum
------------------------------------------------- */
count = 0; vstart = (int)(my_rank*(nvtx / p));
if(my_rank == p-1)
vend = nvtx;
else
vend = (int)((my_rank + 1) * (nvtx / p));
size = vend - vstart;
for(ivert = vstart; ivert < vend ; ivert ++)
{
istart = xadj[ivert];
istop = xadj[ivert+1];
checksum[ivert] = ivert + 1;
for (i = istart; i < istop; i++)
checksum[ivert] += (adjncy[i]+1);
}
MPI_Allgather(checksum ,size ,MPI_INT ,checksum1 ,size ,MPI_INT ,comm);
printf("checksums are %d %d %d %d\n", my_rank, checksum1[0],
checksum1[88], checksum1[200]);
free(deg); free(checksum); free(tmp);
}
Now after executing this on three computer(Because I have given
201 vertex for the size to be similar, I get the checksum1 is same for
all the three processor but that result is obtained by only rank 0
processor. Thats why I need to knpw whether i can have the global
shared memory or someone can give me the solution of this problem.
Peeyush
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