Question

我对MPI相当陌生，所以我不确定为什么此代码无法按预期运行。这个想法是将一个整数传递给一个随机节点，并将其递减直到达到0。当我尝试运行它时，它会将整数传递两次并停顿。有人可以指出正确的方向吗？谢谢！

if (rank == 0)
{
  potato = rand() % 100 + size; // generate a random number between the number of processors and 100
  sendTo = rand() % (size - 1) + 1; // generate a number (not 0) to represent the process to send the potato to

  MPI_Send(&potato, 1, MPI_INT, sendTo, 0, MPI_COMM_WORLD); // send the potato
}

else // any process other than 0
{

  MPI_Recv(&potato, 1, MPI_INT, MPI_ANY_SOURCE, MPI_ANY_TAG, MPI_COMM_WORLD, MPI_STATUS_IGNORE); //receive potato

  if (potato == -1) // check for termination int
    return;

  --potato; // decrement potato

  if (potato != 0)
  {
    do
    {
      sendTo = rand() % (size - 1) + 1; // send to a process 1 through size - 1
    } while (sendTo == rank || sendTo == 0); // make sure it won't send the potato to itself or 0

    printf("Node %d has the potato, passing to node %d.\n", rank, sendTo);
    MPI_Send(&potato, 1, MPI_INT, sendTo, 0, MPI_COMM_WORLD);

  }

  else // potato == 0
  {
    printf("Node %d is it, game over.\n", rank);

    potato = -1;
    for (int i = 1; i < size; ++rank) // send termination message
      MPI_Send(&potato, 1, MPI_INT, i, 0, MPI_COMM_WORLD);
  }
}

输出：

Potato: 44
Node 3 has the potato, Passing to node 2.
Node 2 has the potato, Passing to node 3.

Answer 1

您的代码缺少某些循环。在您的示例中，要使节点3第二次接收到patato，必须再次调用_config.GetValue("Token:Key")。

MPI_Recv

在两次通过后MPI隐含停滞

1 个答案: