Ifpack_UserPartitioner.cpp

00001 /*@HEADER
00002 // ***********************************************************************
00003 //
00004 //       Ifpack: Object-Oriented Algebraic Preconditioner Package
00005 //                 Copyright (2002) Sandia Corporation
00006 //
00007 // Under terms of Contract DE-AC04-94AL85000, there is a non-exclusive
00008 // license for use of this work by or on behalf of the U.S. Government.
00009 //
00010 // This library is free software; you can redistribute it and/or modify
00011 // it under the terms of the GNU Lesser General Public License as
00012 // published by the Free Software Foundation; either version 2.1 of the
00013 // License, or (at your option) any later version.
00014 //
00015 // This library is distributed in the hope that it will be useful, but
00016 // WITHOUT ANY WARRANTY; without even the implied warranty of
00017 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00018 // Lesser General Public License for more details.
00019 //
00020 // You should have received a copy of the GNU Lesser General Public
00021 // License along with this library; if not, write to the Free Software
00022 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
00023 // USA
00024 // Questions? Contact Michael A. Heroux (maherou@sandia.gov)
00025 //
00026 // ***********************************************************************
00027 //@HEADER
00028 */
00029 
00030 #include "Ifpack_ConfigDefs.h"
00031 #include "Ifpack_Partitioner.h"
00032 #include "Ifpack_OverlappingPartitioner.h"
00033 #include "Ifpack_UserPartitioner.h"
00034 #include "Epetra_CrsGraph.h"
00035 
00036 //==============================================================================
00037 int Ifpack_UserPartitioner::ComputePartitions()
00038 {
00039   
00040   if (Map_ == 0)
00041     IFPACK_CHK_ERR(-1);
00042 
00043   // simply copy user's vector
00044   for (int i = 0 ; i < NumMyRows() ; ++i) {
00045     Partition_[i] = Map_[i];
00046   }
00047 
00048   // put together all partitions composed by 1 one vertex
00049   // (if any)
00050   vector<int> singletons(NumLocalParts());
00051   for (unsigned int i = 0 ; i < singletons.size() ; ++i) {
00052     singletons[i] = 0;
00053   }
00054 
00055 #if 0
00056   // may want to uncomment the following to ensure that no
00057   // partitions are in fact singletons
00058   for (int i = 0 ; i < NumMyRows() ; ++i) {
00059     ++singletons[Partition_[i]];
00060   }
00061   
00062   int count = 0;
00063   for (unsigned int i = 0 ; i < singletons.size() ; ++i) {
00064     if (singletons[i] == 1)
00065       ++count;
00066   }
00067 
00068   int index = -1;
00069   for (int i = 0 ; i < NumMyRows() ; ++i) {
00070     int j = Partition_[i];
00071     if (singletons[j] == 1) {
00072       if (index == -1)
00073         index = j;
00074       else
00075         Partition_[i] = index;
00076     }
00077   }
00078 #endif
00079 
00080   return(0);
00081 }

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