Ifpack2 Templated Preconditioning Package Version 1.0
Ifpack2_CreateOverlapGraph.hpp
00001 /*@HEADER
00002 // ***********************************************************************
00003 // 
00004 //       Ifpack2: Tempated Object-Oriented Algebraic Preconditioner Package
00005 //                 Copyright (2009) 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 // 
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00028 */
00029 
00030 #ifndef IFPACK2_CREATEOVERLAPGRAPH_HPP
00031 #define IFPACK2_CREATEOVERLAPGRAPH_HPP
00032 
00033 #include "Ifpack2_ConfigDefs.hpp"
00034 #include "Tpetra_CrsGraph.hpp"
00035 #include "Tpetra_Import.hpp"
00036 #include "Teuchos_RefCountPtr.hpp"
00037 
00038 
00039 namespace Ifpack2 {
00040 
00042 
00045 template<class LocalOrdinal, class GlobalOrdinal, class Node>
00046 Teuchos::RCP<const Tpetra::CrsGraph<LocalOrdinal,GlobalOrdinal,Node> > CreateOverlapGraph(const Teuchos::RCP<const Tpetra::CrsGraph<LocalOrdinal,GlobalOrdinal,Node> >& input_graph, int OverlapLevel)
00047 {
00048   typedef Tpetra::CrsGraph<LocalOrdinal,GlobalOrdinal,Node> GraphType;
00049   typedef Tpetra::Map<LocalOrdinal,GlobalOrdinal,Node> MapType;
00050   typedef Tpetra::Import<LocalOrdinal,GlobalOrdinal,Node> ImportType;
00051 
00052   TEUCHOS_TEST_FOR_EXCEPTION(OverlapLevel < 0, std::runtime_error, "Ifpack2::CreateOverlapGraph: OverlapLevel must be >= 0.");
00053 
00054   Teuchos::RCP<GraphType> OverlapGraph;
00055 
00056   const int numProcs = input_graph->getMap()->getComm()->getSize();
00057   if (OverlapLevel == 0 || numProcs < 2) return input_graph;
00058 
00059   Teuchos::RCP<const MapType> OverlapRowMap = input_graph->getRowMap();
00060 
00061   Teuchos::RCP<const GraphType> OldGraph;
00062   Teuchos::RCP<const MapType> OldRowMap;
00063   const Teuchos::RCP<const MapType> DomainMap = input_graph->getDomainMap();
00064   const Teuchos::RCP<const MapType> RangeMap = input_graph->getRangeMap();
00065 
00066   for (int level=1; level <= OverlapLevel; level++) {
00067     OldGraph = OverlapGraph;
00068     OldRowMap = OverlapRowMap;
00069 
00070     Teuchos::RCP<const ImportType> OverlapImporter = OldGraph->getImporter();
00071     OverlapRowMap = OverlapImporter->getTargetMap();
00072     if (level<OverlapLevel) {
00073       OverlapGraph = Teuchos::rcp( new GraphType(OverlapRowMap, 0) );
00074     }
00075     else {
00076       // On last iteration, we want to filter out all columns except those that
00077       // correspond to rows in the graph.  This assures that our matrix is square
00078       OverlapGraph = Teuchos::rcp( new GraphType(OverlapRowMap, OverlapRowMap, 0) );
00079     }
00080 
00081     OverlapGraph->doImport(*input_graph, *OverlapImporter, Tpetra::INSERT);
00082     OverlapGraph->fillComplete(DomainMap, RangeMap);
00083   }
00084 
00085   return OverlapGraph;
00086 }
00087 
00088 }//namespace Ifpack2
00089 
00090 #endif // IFPACK2_CREATEOVERLAPGRAPH_HPP
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