#define MAXLEN 10000
-void main()
+int main( int argc, char *argv[] )
{
- int out[1000000],in[1000000],i,j,k;
+#define N 1000000
+ int *out, *in,i,j,k;
int myself,tasks;
- MPI_Init(0,0);
+ out = malloc(N*sizeof(int));
+ in = malloc(N*sizeof(int));
+ if ((out==NULL) || (in==NULL)) {
+ printf("Error: cannot allocate N bytes for in or out arrays\n");
+ exit(1);
+ }
+ MPI_Init( &argc,&argv );
MPI_Comm_rank(MPI_COMM_WORLD,&myself);
MPI_Comm_size(MPI_COMM_WORLD,&tasks);
for(j=1;j<=MAXLEN;j*=10) {
- for(i=0;i<j*tasks;i++) out[i] = myself;
-
- MPI_Alltoall(out,j,MPI_INT,in,j,MPI_INT,MPI_COMM_WORLD);
-
- for(i=0;i<tasks;i++) {
- for(k=0;k<j;k++) {
- if(in[k+i*j] != i) { printf("bad answer (%d) at index %d of %d (should be %d)\n",in[k+i*j],k+i*j,j*tasks,i); break; }
- }
- }
+ if ( 0 == myself ) {
+ printf("* calling MPI_Alltoall with buffers of %d ints\n",j);
+ }
+ for(i=0;i<j*tasks;i++)
+ out[i] = myself;
+
+ MPI_Alltoall(out,j,MPI_INT,in,j,MPI_INT,MPI_COMM_WORLD);
+
+ for(i=0;i<tasks;i++) {
+ for(k=0;k<j;k++) {
+ if(in[k+i*j] != i) {
+ printf("<%d> bad answer (%d) at index %d of %d (should be %d)\n",myself,in[k+i*j],k+i*j,j*tasks,i);
+ break;
+ }
+ }
+ }
}
MPI_Barrier(MPI_COMM_WORLD);
if(myself==0) printf("TEST COMPLETE\n");