Example : Collect.C

Classes/Techniques Demonstrated :

• Threads
• Barrier
• Barrier

Collect.C

class MyThread : public HPCxx_Thread {
  HPCxx_Collective<int> &coll;
  int *infoAr, *newAr;
  int totalThreads, myId, count, myCollectKey;
  
public:
  MyThread(int n, int id, HPCxx_Collective<int> &_coll):
    totalThreads(n), myId(id), coll(_coll), HPCxx_Thread()
  {
      myCollectKey=coll.acquireKey();
  }
  
  void run() {
    int size=10;
    int total=0;
    infoAr=new int[10];
    
    srand48((int)infoAr);
    cout << "Thread " << myId << " generating array values..." << endl;
 
    for(count=0; count<10; count++) {
      infoAr[count]=(int)(1000*drand48());
    }
    
    cout << "Thread " << myId << " passing to collection..." << endl;

    newAr=coll.gather(myCollectKey, infoAr, size);

    for(count=0; count<totalThreads*10+1; count++) {
      if(myId==0) {
	cout << "newAr[" << count << "] = " << newAr[count] << endl;
      }
      total+=newAr[count];
    }
    
    cout << "Thread " << myId << "computed sum " << total << "  Size returned was " << size << endl;
  } 
};

int foo(int n, HPCxx_Barrier barrier, HPCxx_Collective<int> coll){
  MyThread *t[100];
  int total=0, count=0, collectKey0;
  int dummy=0;
  int size=1, *infoAr;
  
  for(int i = 0; i < n; i++){
    t[i] = new MyThread(n, i, coll);
    t[i]->start();
  }  

  cout << "DONE" << endl << flush;
  return 0;
}


int main(int argc, char **argv)
{
  HPCxx_Group *g;
  int n;

  hpcxx_init(argc, argv, g);

  cout << "INPUT" << endl << flush;
  cout << "Number of threads : " << endl << flush;
  cin >> n;
  g->setNumThreads(n);
  HPCxx_Barrier barrier(*g);
  HPCxx_Collective<int> coll(g);
  foo(n, barrier, coll);
  return hpcxx_exit(g);
}