blocked_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
 *
 *  add.h
 *  April 24, 2012
 *
 */
 
#ifndef TILEDARRAY_PMAP_BLOCKED_PMAP_H__INCLUDED
#define TILEDARRAY_PMAP_BLOCKED_PMAP_H__INCLUDED
 
#include <TiledArray/pmap/pmap.h>
 
namespace TiledArray {
namespace detail {
 
 
class BlockedPmap : public Pmap {
 protected:
  // Import Pmap protected variables
  using Pmap::procs_;  
  using Pmap::rank_;   
  using Pmap::size_;   
 
 private:
  const size_type block_size_;         
  const size_type remainder_;          
  const size_type block_size_plus_1_;  
  const size_type block_size_plus_1_times_remainder_;  
  const size_type local_first_;  
  const size_type local_last_;   
 
 public:
  typedef Pmap::size_type size_type;  
 
 
  BlockedPmap(World& world, size_type size)
      : Pmap(world, size),
        block_size_(size_ / procs_),
        remainder_(size_ % procs_),
        block_size_plus_1_(block_size_ + 1),
        block_size_plus_1_times_remainder_(remainder_ * block_size_plus_1_),
        local_first_(rank_ * block_size_ +
                     std::min<size_type>(rank_, remainder_)),
        local_last_((rank_ + 1) * block_size_ +
                    std::min<size_type>((rank_ + 1), remainder_)) {
    this->local_size_ = local_last_ - local_first_;
  }
 
  virtual ~BlockedPmap() {}
 
 
  virtual size_type owner(const size_type tile) const {
    TA_ASSERT(tile < size_);
    return (tile < block_size_plus_1_times_remainder_
                ? tile / block_size_plus_1_
                : ((tile - block_size_plus_1_times_remainder_) / block_size_) +
                      remainder_);
  }
 
 
  virtual bool is_local(const size_type tile) const {
    return ((tile >= local_first_) && (tile < local_last_));
  }
 
  virtual const_iterator begin() const {
    return Iterator(*this, local_first_, local_last_, local_first_, false);
  }
  virtual const_iterator end() const {
    return Iterator(*this, local_first_, local_last_, local_last_, false);
  }
 
};  // class BlockedPmap
 
}  // namespace detail
}  // namespace TiledArray
 
#endif  // TILEDARRAY_PMAP_BLOCKED_PMAP_H__INCLUDED