使用MPI优雅退出

Question

如果Rdinput返回错误，我会尝试优雅地退出我的程序。

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

#define MASTER 0
#define Abort(x) MPI_Abort(MPI_COMM_WORLD, x)
#define Bcast(send_data, count, type) MPI_Bcast(send_data, count, type, MASTER, GROUP) //root --> MASTER
#define Finalize() MPI_Finalize()

int main(int argc, char **argv){

  //Code

  if( rank == MASTER ) {
    time (&start);
    printf("Initialized at %s\n", ctime (&start) );      
    //Read file
    error = RdInput();
  }

  Bcast(&error, 1, INT); Wait();

  if( error = 1 ) MPI_Abort(1);

  //Code

  Finalize();
}

程序输出：

mpirun -np 2 code.x 
--------------------------------------------------------------------------
MPI_ABORT was invoked on rank 0 in communicator MPI_COMM_WORLD 
with errorcode 1.

NOTE: invoking MPI_ABORT causes Open MPI to kill all MPI processes.
You may or may not see output from other processes, depending on
exactly when Open MPI kills them.
--------------------------------------------------------------------------
Initialized at Wed May 30 11:34:46 2012
Error [RdInput]: The file "input.mga" is not available!
--------------------------------------------------------------------------
mpirun has exited due to process rank 0 with PID 7369 on
node einstein exiting improperly. There are two reasons this could occur:

//More error message.

如何才能在不打印此巨大错误消息的情况下优雅地退出MPI程序？

Answer 1

如果你的代码中有这样的逻辑：

Bcast(&error, 1, INT);
if( error = 1 ) MPI_Abort(1); 

然后你就快完成了(尽管在广播之后你不需要任何形式的等待)。正如您已经发现的，诀窍在于MPI_Abort()并不“优雅”；它基本上是在发生严重错误时以任何可能的方式关闭程序。

在这种情况下，现在每个人都同意广播后的错误代码，所以只需优雅地结束您的程序：

   MPI_Bcast(&error, 1, MPI_INT, MASTER, MPI_COMM_WORLD);
   if (error != 0) {
       if (rank == 0) {
           fprintf(stderr, "Error: Program terminated with error code %d\n", error);
       }
       MPI_Finalize();
       exit(error);
   } 

调用MPI_Finalize()并继续使用更多的MPI内容是错误的，但这不是您在这里要做的，所以您很好。