#include "mpi.h"
#include <stdio.h>

/*****************************************************************************

 * Function: bcast_linear

 * Return: int

 * Inputs:
    buff: send input buffer
    count: number of elements to send
    data_type: data type of elements being sent
    root: source of data
    comm: communicator

 * Descrp: broadcasts using a linear scheme (root loops sending to all nodes)

 * Auther: LAM, but modified by Ahmad Faraj

 ****************************************************************************/
int
bcast_flattree(void * buff, int count, MPI_Datatype data_type, int root, 
	     MPI_Comm comm)
{
  MPI_Request * req_ptr;
  MPI_Request * reqs;

  int i, rank, num_procs;
  int tag = 1;
  int success = 0;
  int failure = 1;
  
  MPI_Comm_rank(comm, &rank);
  MPI_Comm_size(comm, &num_procs);

  if (rank != root)
    {
      MPIC_Recv(buff, count, data_type, root, tag, comm,
		MPI_STATUS_IGNORE);
      return success;
    }

  reqs = (MPI_Request *) malloc((num_procs - 1) * sizeof(MPI_Request));
  if (!reqs)
    {
      printf("allgather-gather-bcast:66: cannot allocate memory\n");
      MPI_Finalize();
      exit(failure);
    }

  req_ptr = reqs;
  
  // Root sends data to all others
  for (i = 0; i < num_procs; i++)
    {
      if (i == rank)
	continue;
      MPIC_Isend(buff, count, data_type, i, tag, comm, req_ptr++);
    }
  
  // wait on all requests
  MPI_Waitall(num_procs - 1, reqs, MPI_STATUSES_IGNORE);
  
  free(reqs);
  return success;
}