TbbTsqr_UnCacheBlockTask.hpp

// @HEADER
// ***********************************************************************
//
//                 Anasazi: Block Eigensolvers Package
//                 Copyright (2010) Sandia Corporation
//
// Under terms of Contract DE-AC04-94AL85000, there is a non-exclusive
// license for use of this work by or on behalf of the U.S. Government.
//
// This library is free software; you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; either version 2.1 of the
// License, or (at your option) any later version.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
// USA
// Questions? Contact Michael A. Heroux (maherou@sandia.gov)
//
// ***********************************************************************
// @HEADER

#ifndef __TSQR_TBB_UnCacheBlockTask_hpp
#define __TSQR_TBB_UnCacheBlockTask_hpp

#include <tbb/task.h>
#include <TbbTsqr_Partitioner.hpp>
#include <Tsqr_SequentialTsqr.hpp>


namespace TSQR {
  namespace TBB {
    
    template< class LocalOrdinal, class Scalar >
    class UnCacheBlockTask : public tbb::task {
    public:
      typedef MatView< LocalOrdinal, Scalar > mat_view;
      typedef ConstMatView< LocalOrdinal, Scalar > const_mat_view;
      typedef std::pair< mat_view, mat_view > split_t;
      typedef std::pair< const_mat_view, const_mat_view > const_split_t;

      UnCacheBlockTask (const size_t P_first__, 
      const size_t P_last__,
      mat_view& A_out,
      const_mat_view& A_in,
      const SequentialTsqr< LocalOrdinal, Scalar >& seq) :
  P_first_ (P_first__), 
  P_last_ (P_last__), 
  A_out_ (A_out), 
  A_in_ (A_in), 
  seq_ (seq)
      {}

      tbb::task* execute () {
  using tbb::task;

  if (P_first_ > P_last_ || A_out_.empty() || A_in_.empty())
    return NULL;
  else if (P_first_ == P_last_)
    {
      seq_.un_cache_block (A_out_.nrows(), A_out_.ncols(), 
         A_out_.get(), A_out_.lda(), A_in_.get());
      return NULL;
    }
  else
    {
      // "c": continuation task
      tbb::empty_task& c = *new( allocate_continuation() ) tbb::empty_task;

      // Recurse on two intervals: [P_first, P_mid] and [P_mid+1, P_last]
      const size_t P_mid = (P_first_ + P_last_) / 2;
      split_t out_split = 
        partitioner_.split (A_out_, P_first_, P_mid, P_last_, false);
      const_split_t in_split = 
        partitioner_.split (A_in_, P_first_, P_mid, P_last_, true);

      UnCacheBlockTask& topTask = *new( c.allocate_child() )
        UnCacheBlockTask (P_first_, P_mid, out_split.first, 
            in_split.first, seq_);
      UnCacheBlockTask& botTask = *new( c.allocate_child() )
        UnCacheBlockTask (P_mid+1, P_last_, out_split.second, 
            in_split.second, seq_);
      // Set reference count of parent (in this case, the
      // continuation task) to 2 (since 2 children -- no
      // additional task since no waiting).
      c.set_ref_count (2);
      c.spawn (botTask);
      return &topTask; // scheduler bypass optimization
    }
      }

    private:
      size_t P_first_, P_last_;
      mat_view A_out_;
      const_mat_view A_in_;
      SequentialTsqr< LocalOrdinal, Scalar > seq_;
      Partitioner< LocalOrdinal, Scalar > partitioner_;
    };

  } // namespace TBB
} // namespace TSQR


#endif // __TSQR_TBB_UnCacheBlockTask_hpp