Zoltan2_MatrixPartitioningSolution.hpp

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// @HEADER
// *****************************************************************************
//   Zoltan2: A package of combinatorial algorithms for scientific computing
//
// Copyright 2012 NTESS and the Zoltan2 contributors.
// SPDX-License-Identifier: BSD-3-Clause
// *****************************************************************************
// @HEADER

#ifndef _ZOLTAN2_MATRIXPARTITIONINGSOLUTION_HPP_
#define _ZOLTAN2_MATRIXPARTITIONINGSOLUTION_HPP_

// namespace Zoltan2 {
// template <typename Adapter>
// class PartitioningSolution;
// }

// #include <Zoltan2_Environment.hpp>
// #include <Zoltan2_Solution.hpp>
// #include <Zoltan2_GreedyMWM.hpp>
// #include <Zoltan2_Algorithm.hpp>
// #include <Zoltan2_CoordinatePartitioningGraph.hpp>
// #include <cmath>
// #include <algorithm>
// #include <vector>
// #include <limits>


namespace Zoltan2 {

template <typename Adapter>
  class MatrixPartitioningSolution : public Solution
{
public:

#ifndef DOXYGEN_SHOULD_SKIP_THIS
  typedef typename Adapter::gno_t gno_t;
  typedef typename Adapter::scalar_t scalar_t;
  typedef typename Adapter::lno_t lno_t;
  typedef typename Adapter::part_t part_t;
  typedef typename Adapter::user_t user_t;
#endif

  MatrixPartitioningSolution( const RCP<const Environment> &env,
    const RCP<const Comm<int> > &comm,
    const RCP<Algorithm<Adapter> > &algorithm = Teuchos::null);


  // Information that the algorithm may wish to query.

  // Method used by the algorithm to set results.

  void setIDLists(ArrayRCP<part_t> &rowIDs,ArrayRCP<part_t> &colIDs, 
      ArrayRCP<part_t> &domainIDs, ArrayRCP<part_t> &rangeIDs);


  // TODO: Figure out if I want to do this
  // 
  // /*! \brief Remap a new partition for maximum overlap with an input partition.
  //  *
  //  * Assumptions for this version:
  //  * input part assignment == processor rank for every local object.
  //  * assuming nGlobalParts <= num ranks
  //  * TODO:  Write a version that takes the input part number as input;
  //  *        this change requires input parts in adapters to be provided in
  //  *        the Adapter.
  //  * TODO:  For repartitioning, compare to old remapping results; see Zoltan1.
  //  */

  // void RemapParts();

  // ////////////////////////////////////////////////////////////////////
  // /* Return the weight of objects staying with a given remap.
  //  * If remap is NULL, compute weight of objects staying with given partition
  //  */
  // long measure_stays(part_t *remap, int *idx, part_t *adj, long *wgt,
  //                    part_t nrhs, part_t nlhs)
  // {
  //   long staying = 0;
  //   for (part_t i = 0; i < nrhs; i++) { 
  //     part_t k = (remap ? remap[i] : i);
  //     for (part_t j = idx[k]; j < idx[k+1]; j++) { 
  //       if (i == (adj[j]-nlhs)) {
  //         staying += wgt[j];
  //         break;
  //       }
  //     }
  //   }
  //   return staying;
  // }

  // Results that may be queried by the user, by migration methods,
  // or by metric calculation methods.
  // We return raw pointers so users don't have to learn about our
  // pointer wrappers.

  inline const RCP<const Comm<int> > &getCommunicator() const { return comm_;}

  inline const RCP<const Environment> &getEnvironment() const { return env_;}


  const gno_t *getRowIdsView() const
  {  
    if (rowIDs_.size() > 0) 
      return rowIDs_.getRawPtr();
    else                   
      return NULL;
  }


  const gno_t *getColIdsView() const
  {  
    if (colIDs_.size() > 0) 
      return colIDs_.getRawPtr();
    else                   
      return NULL;
  }


  // /*! \brief Returns the process list corresponding to the global ID list.
  //     \return The return value is a NULL pointer if part IDs are
  //               synonomous with process IDs.
  //  */
  // const int *getProcListView() const {
  //   if (procs_.size() > 0) return procs_.getRawPtr();
  //   else                   return NULL;
  // }


  // /*! \brief Get the processes containing a part.
  //  *  \param partId a part number from 0 to one less than the global number
  //  *                of parts.
  //  *  \param procMin on return will be set to minimum proc number
  //  *  \param procMax on return will be set to maximum proc number
  //  *
  //  * Normally \c procMin and \c procMax are the same value and a part
  //  * is assigned to one process.  But if there are more processes than
  //  * parts, it's possible that a part will be divided across more than
  //  * one process.
  //  */
  // void getProcsForPart(part_t partId, part_t &procMin, part_t &procMax) const
  // {
  //   env_->localInputAssertion(__FILE__, __LINE__, "invalid part id",
  //     partId >= 0 && partId < nGlobalParts_, BASIC_ASSERTION);

  //   partToProcsMap(partId, procMin, procMax);
  // }

private:


  // void setPartDistribution();

  // void setPartSizes(ArrayView<ArrayRCP<part_t> > reqPartIds,
  //   ArrayView<ArrayRCP<scalar_t> > reqPartSizes);

  // void computePartSizes(int widx, ArrayView<part_t> ids,
  //   ArrayView<scalar_t> sizes);

  // void broadcastPartSizes(int widx);


  RCP<const Environment> env_;             // has application communicator
  const RCP<const Comm<int> > comm_;       // the problem communicator

  //  part_t nGlobalParts_;// target global number of parts

  // The algorithm sets these values upon completion.


  // There is a decision to made to decide what to store in the solution.
  // 1. One possibility is to store part numbers for each local id.  This
  //    is what was implemented for PartitioninSolution and this was advantageous
  //    for this case since (unlike 2) an extra communication was not needed
  //    after each process assigned its localids a part.  
  // 2. Alternatively, each process can store the set of ids that it owns.  For 1D
  //    this would require an additional communication step to place the ids to the
  //    correct processor.  This would also complicated the case where number of
  //    parts != number of processes.  This is similar to what is needed to build
  //    row or column epetra/tpetra maps.
  //
  // However, things are more complicated for 2D Cartesian partitioning (maybe all
  // of partitioning).  In this case, we need to assign matrix nonzeros to both
  // a process row and a process column.  This means that extra communication will
  // be needed for option #1 in order to determine both of these, which are needed
  // to determine a part assignment for a given nonzero (or alternatively both the
  // process rows and column assignments for a 2D block of matrix rows and columns,
  // although this may complicated part assignment).
  // This eliminates one of the advantages of method 1 vs. method 2.  

  // For method 2 and 2D, each process would store the set of rowIDs and columnIDs
  // for which it owns the nonzeros. Method 2 still
  // has the disadvantage that it becomes more complicated for #parts != #procs. 
  // However, it would have what is needed to build both the row and column ids.
  // For now, we are going with Method #2.

  // Need a plan to handle #parts != #procs

  ArrayRCP<gno_t> rowIDs_;      // Row Ids assigned to this process
  ArrayRCP<gno_t> colIDs_;      // Col Ids assigned to this process

  ArrayRCP<gno_t> domainIDs_;     // Domain vector Ids assigned to this process
  ArrayRCP<gno_t> rangeIDs_;      // Range vector Ids assigned to this process


  bool haveSolution_;


  // Algorithm used to compute the solution; 
  // Not sure if this is necessary
  const RCP<Algorithm<Adapter> > algorithm_;
};

template <typename Adapter>
MatrixPartitioningSolution<Adapter>::MatrixPartitioningSolution(const RCP<const Environment> &env,
    const RCP<const Comm<int> > &comm, const RCP<Algorithm<Adapter> > &algorithm)
    : env_(env), comm_(comm), rowIDs_(), colIDs_(), haveSolution_(false), 
      algorithm_(algorithm)
{
  env_->memory("After construction of solution");
}

template <typename Adapter>
void MatrixPartitioningSolution<Adapter>::setIDLists(ArrayRCP<part_t> &rowIDs,ArrayRCP<part_t> &colIDs, 
                       ArrayRCP<part_t> &domainIDs, ArrayRCP<part_t> &rangeIDs)
{
  env_->debug(DETAILED_STATUS, "Entering setParts");

  rowIDs_=rowIDs;
  colIDs_=colIDs;
  domainIDs_=domainIDs;
  rangeIDs_=rangeIDs;

  haveSolution_ = true;

  env_->memory("After Solution has processed algorithm's answer");
  env_->debug(DETAILED_STATUS, "Exiting setParts");
}




}  // namespace Zoltan2

#endif