Question

所以我尝试使用MPI实现一个在C中执行并行向量向量加法的函数。

不幸的是，当我尝试运行它时，我收到一个很大的错误，表明存在分段错误。

这是系统内存回溯后的输出。

===================================================================================
=   BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES
=   PID 12581 RUNNING AT hbaum-pc
=   EXIT CODE: 6
=   CLEANING UP REMAINING PROCESSES
=   YOU CAN IGNORE THE BELOW CLEANUP MESSAGES
===================================================================================
YOUR APPLICATION TERMINATED WITH THE EXIT STRING: Aborted (signal 6)
This typically refers to a problem with your application.

这是我的函数代码：

double* vector_vector_addition_parallel(double* a, double* b, int length)
{
  int rank, size, error;
  double* result = (double*)malloc(sizeof(double)*length);

  error = MPI_Init(NULL,NULL);
  error = MPI_Comm_size(MPI_COMM_WORLD,&size);
  error = MPI_Comm_rank(MPI_COMM_WORLD,&rank);

  int sublist_length = (int)(length/size);

  double* sub_a = (double*)malloc(sizeof(double) * sublist_length);
  double* sub_b = (double*)malloc(sizeof(double) * sublist_length);


  error = MPI_Scatter(a, sublist_length, MPI_DOUBLE, sub_a, sublist_length, MPI_DOUBLE, 0, MPI_COMM_WORLD);
  error = MPI_Scatter(b, sublist_length, MPI_DOUBLE, sub_b, sublist_length, MPI_DOUBLE, 0, MPI_COMM_WORLD);

  double* buffer = (double*)malloc(sizeof(double)*sublist_length);
  for(int i = 0; i < sublist_length; i++)
  {
    buffer[i] = sub_a[i] + sub_b[i];
  }

  error = MPI_Gather(buffer,sublist_length,MPI_DOUBLE,result,length,MPI_DOUBLE,0,MPI_COMM_WORLD);

  error = MPI_Finalize();

  return result;
}

以下是我的代码：

int main(int argc, char** argv)
{
  double a[8] = {1.0,3.0,5.0,7.0,9.0,11.0,13.0,15.0};
  double b[8] = {2.0,4.0,6.0,8.0,10.0,12.0,14.0,16.0};
  double* vec = vector_vector_addition_parallel(a,b,8);
  return 0;
}

我发现问题在于MPI_Gather调用，因为当我发表评论时，没有错误。但是，我显然需要使用MPI_Gather函数。

我也尝试使用gdb调试代码，但gdb完全没有看错。当我在gdb上运行它并使用printf（）输出结果向量时，它会输出正确的结果！

我该怎么做才能阻止错误发生？

提前致谢

MPI终止不良

0 个答案: