Zoltan2_AlgSortedDegree.hpp

Go to the documentation of this file.

// @HEADER
//
// ***********************************************************************
//
//   Zoltan2: A package of combinatorial algorithms for scientific computing
//                  Copyright 2012 Sandia Corporation
//
// Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
// the U.S. Government retains certain rights in this software.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// 3. Neither the name of the Corporation nor the names of the
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY SANDIA CORPORATION "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SANDIA CORPORATION OR THE
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Questions? Contact Karen Devine      (kddevin@sandia.gov)
//                    Erik Boman        (egboman@sandia.gov)
//                    Siva Rajamanickam (srajama@sandia.gov)
//
// ***********************************************************************
//
// @HEADER
#ifndef _ZOLTAN2_SORTEDDEGREE_HPP_
#define _ZOLTAN2_SORTEDDEGREE_HPP_
 
#include <Zoltan2_Algorithm.hpp>
#include <Zoltan2_GraphModel.hpp>
#include <Zoltan2_OrderingSolution.hpp>
#include <Zoltan2_Sort.hpp>
#include <algorithm>
 
 
 
namespace Zoltan2{
 
template <typename Adapter>
class AlgSortedDegree : public Algorithm<Adapter>
{
  private:
 
  const RCP<GraphModel<Adapter> > model;
  const RCP<Teuchos::ParameterList> pl;
  const RCP<const Teuchos::Comm<int> > comm;
 
  public:
 
  typedef typename Adapter::lno_t lno_t;
  typedef typename Adapter::gno_t gno_t;
  typedef typename Adapter::offset_t offset_t;
  typedef typename Adapter::scalar_t scalar_t;
 
  AlgSortedDegree(
    const RCP<GraphModel<Adapter> > &model__,
    const RCP<Teuchos::ParameterList> &pl__,
    const RCP<const Teuchos::Comm<int> > &comm__
  ) : model(model__), pl(pl__), comm(comm__)
  {
  }
 
  int globalOrder(const RCP<GlobalOrderingSolution<gno_t> > &solution)
  {
     throw std::logic_error(
       "AlgSortedDegree does not yet support global ordering.");
  }
 
  int localOrder(const RCP<LocalOrderingSolution<lno_t> > &solution)
  {
    int ierr= 0;
  
    HELLO;
  
    lno_t *perm = solution->getPermutationView();
    if (perm==0){
      // Throw exception
      std::cerr << "perm is NULL" << std::endl;
      ierr = -1;
    }
  
    // Get local graph.
    const size_t nVtx = model->getLocalNumVertices();
    ArrayView<const gno_t> edgeIds;
    ArrayView<const offset_t> offsets;
    ArrayView<StridedData<lno_t, scalar_t> > wgts;
    model->getEdgeList(edgeIds, offsets, wgts);
 
  
    // Store degrees together with index so we can sort.
    Teuchos::Array<std::pair<lno_t, offset_t> >  degrees(nVtx);
    for (lno_t i=0; i<(lno_t)nVtx; i++){
      degrees[i].first = i;
      degrees[i].second  = offsets[i+1] - offsets[i];
    }
  
    // Sort degrees.
    SortPairs<lno_t,offset_t> zort;
    bool inc = true; // TODO: Add user parameter
    zort.sort(degrees, inc);
  
    // Copy permuted indices to perm.
    for (lno_t i=0; i<(lno_t)nVtx; i++){
      perm[i] = degrees[i].first;
    }
  
    solution->setHavePerm(true);
    return ierr;
  }
  
};
}
#endif