hash_pmap.h

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/*
 *  This file is a part of TiledArray.
 *  Copyright (C) 2013  Virginia Tech
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *  Justus Calvin
 *  Department of Chemistry, Virginia Tech
 *
 *  hash_pmap.h
 *  May 4, 2012
 *
 */
 
#ifndef TILEDARRAY_PMAP_HASH_PMAP_H__INCLUDED
#define TILEDARRAY_PMAP_HASH_PMAP_H__INCLUDED
 
#include <TiledArray/pmap/pmap.h>
 
namespace TiledArray {
namespace detail {
 
class HashPmap : public Pmap {
 protected:
  // Import Pmap protected variables
  using Pmap::procs_;  
  using Pmap::rank_;   
  using Pmap::size_;   
 
 private:
  const madness::hashT seed_;  
 
 public:
  typedef Pmap::size_type size_type;  
 
 
  HashPmap(World& world, const size_type size, madness::hashT seed = 0ul)
      : Pmap(world, size), seed_(seed) {}
 
  virtual ~HashPmap() {}
 
 
  virtual size_type owner(const size_type tile) const {
    TA_ASSERT(tile < size_);
    madness::hashT seed = seed_;
    madness::hash_combine(seed, tile);
    return (seed % procs_);
  }
 
 
  virtual bool is_local(const size_type tile) const {
    return HashPmap::owner(tile) == rank_;
  }
 
  virtual bool known_local_size() const { return false; }
 
};  // class HashPmap
 
}  // namespace detail
}  // namespace TiledArray
 
#endif  // TILEDARRAY_PMAP_HASH_PMAP_H__INCLUDED