vtkMPIPixelView.h

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/*=========================================================================
 
  Program:   Visualization Toolkit
  Module:    vtkMPIPixelView.h
 
  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
 
     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.
 
=========================================================================*/
#ifndef vtkMPIPixelView_h
#define vtkMPIPixelView_h
 
#include "vtkPixelExtent.h" // for pixel extent
#include "vtkMPI.h" // for mpi
#include "vtkMPIPixelTT.h" // for type traits
#include <iostream> // for cerr
 
//-----------------------------------------------------------------------------
template<typename T>
int vtkMPIPixelViewNew(
      const vtkPixelExtent &domain,
      const vtkPixelExtent &decomp,
      int nComps,
      MPI_Datatype &view)
{
  #ifndef NDEBUG
  int mpiOk=0;
  MPI_Initialized(&mpiOk);
  if (!mpiOk)
    {
    std::cerr << "This class requires the MPI runtime." << std::endl;
    return -1;
    }
  #endif
 
  int iErr;
 
  MPI_Datatype nativeType;
  iErr=MPI_Type_contiguous(
        nComps,
        vtkMPIPixelTT<T>::MPIType,
        &nativeType);
  if (iErr)
    {
    return -2;
    }
 
  int domainDims[2];
  domain.Size(domainDims);
 
  int domainStart[2];
  domain.GetStartIndex(domainStart);
 
  int decompDims[2];
  decomp.Size(decompDims);
 
  int decompStart[2];
  decomp.GetStartIndex(decompStart, domainStart);
 
  // use a contiguous type when possible.
  if (domain==decomp)
    {
    unsigned long long nCells=decomp.Size();
    iErr=MPI_Type_contiguous((int)nCells, nativeType, &view);
    if (iErr)
      {
      MPI_Type_free(&nativeType);
      return -3;
      }
    }
  else
    {
    iErr=MPI_Type_create_subarray(
        2,
        domainDims,
        decompDims,
        decompStart,
        MPI_ORDER_FORTRAN,
        nativeType,
        &view);
    if (iErr)
      {
      MPI_Type_free(&nativeType);
      return -4;
      }
    }
  iErr=MPI_Type_commit(&view);
  if (iErr)
    {
    MPI_Type_free(&nativeType);
    return -5;
    }
 
  MPI_Type_free(&nativeType);
 
  return 0;
}
 
#endif
// VTK-HeaderTest-Exclude: vtkMPIPixelView.h