CODEWITHSUNDEEP
c++mpi
Ashmohan
Ashmohan

Reputation: 491

Fatal Error in MPI_Wait

Here is the output for a source code implementation shown below. I am not sure what it means and how i should remedy the code. 

 aborting job:
 Fatal error in MPI_Wait: Invalid MPI_Request, error stack:
 MPI_Wait(139): MPI_Wait(request=0xffffd6a4, status0xffffd690) failed
 MPI_Wait(75) : Invalid MPI_Request
 rank 0 in job 1 <processor #) caused collective abort of all ranks
 exit status of rank 0: return code 13

SOURCE CODE:

 #define Rows 48 
 ...

  double *northedge1 = new double[Rows];
  double *northofnorthedge3 = new double[Rows];
  ...
  ...

  int main (int argc, char *argv[])
  {
  ....
  ....

  MPI_Request send_request, recv_request;
  ...
  ...


  if ((my_rank) == 1)
  {
  MPI_Isend(northedge1, Rows, MPI_DOUBLE, my_rank+2, 0, MPI_COMM_WORLD, &send_request); 
  }

  if ((my_rank) == 3)
  {
  MPI_Irecv(northofnorthedge3, Rows, MPI_DOUBLE, my_rank-2, MPI_ANY_TAG, MPI_COMM_WORLD,   
  &send_request);
  }


  MPI_Wait(&send_request, &status);
  .....
  MPI_Finalize ()

Upvotes: 1

Views: 4672

Answers (1)

Jonathan Dursi
Jonathan Dursi

Reputation: 50927

It looks like you're calling the MPI_Wait() even from rank 0, even though you're only doing nonblocking communications in rank 1 and 3. So there's no valid send_request in rank 0, so the MPI_Wait is invalid. In the above, it looks like you should have

 if ( (my_rank == 1) || (my_rank == 3))   
      MPI_Wait(&send_request, &status);

Upvotes: 2

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