vtkMPIUtilities.h

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// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause
#ifndef vtkMPIUtilities_h
#define vtkMPIUtilities_h
 
#include "vtkMPIController.h"   // For vtkMPIController
#include "vtkStringFormatter.h" // For vtk::print
 
#include <cassert> // For assert
#include <string>  // For std::string
 
namespace vtkMPIUtilities
{
VTK_ABI_NAMESPACE_BEGIN


template <typename... T>
void Print(vtkMPIController* comm, const char* format, T&&... args)
{
  assert(comm != nullptr);
  if (comm->GetLocalProcessId() == 0)
  {
    vtk::print(vtk::runtime(format), std::forward<T>(args)...);
    std::fflush(stdout);
  }
  comm->Barrier();
}



template <typename... T>
void SynchronizedPrint(vtkMPIController* comm, const char* format, T&&... args)
{
  assert(comm != nullptr);
  int rank = comm->GetLocalProcessId();
  int numRanks = comm->GetNumberOfProcesses();
 
  vtkMPICommunicator::Request rqst;
  int* nullmsg = nullptr;
 
  if (rank == 0)
  {
    // STEP 0: print message
    vtk::print("[{:d}]: ", rank);
    std::fflush(stdout);
 
    vtk::print(vtk::runtime(format), std::forward<T>(args)...);
    std::fflush(stdout);
 
    // STEP 1: signal next process (if any) to print
    if (numRanks > 1)
    {
      comm->NoBlockSend(nullmsg, 0, rank + 1, 0, rqst);
    } // END if
  } // END first rank
  else if (rank == numRanks - 1)
  {
    // STEP 0: Block until previous process completes
    comm->Receive(nullmsg, 0, rank - 1, 0);
 
    // STEP 1: print message
    vtk::print("[{:d}]: ", rank);
 
    vtk::print(vtk::runtime(format), std::forward<T>(args)...);
    std::fflush(stdout);
  } // END last rank
  else
  {
    // STEP 0: Block until previous process completes
    comm->Receive(nullmsg, 0, rank - 1, 0);
 
    // STEP 1: print message
    vtk::print("[{:d}]: ", rank);
 
    vtk::print(vtk::runtime(format), std::forward<T>(args)...);
    std::fflush(stdout);
 
    // STEP 2: signal next process to print
    comm->NoBlockSend(nullmsg, 0, rank + 1, 0, rqst);
  }
 
  comm->Barrier();
}

VTK_ABI_NAMESPACE_END
} // END namespace vtkMPIUtilities
 
#endif // vtkMPIUtilities_h
// VTK-HeaderTest-Exclude: vtkMPIUtilities.h