text: /*
  Copyright (c) 2009-2017, UT-Battelle, LLC
  All rights reserved
  
  [DMRG++, Version 4.]
  [by G.A., Oak Ridge National Laboratory]
  
  UT Battelle Open Source Software License 11242008
  
  OPEN SOURCE LICENSE
  
  Subject to the conditions of this License, each
  contributor to this software hereby grants, free of
  charge, to any person obtaining a copy of this software
  and associated documentation files (the "Software"), a
  perpetual, worldwide, non-exclusive, no-charge,
  royalty-free, irrevocable copyright license to use, copy,
  modify, merge, publish, distribute, and/or sublicense
  copies of the Software.
  
  1. Redistributions of Software must retain the above
  copyright and license notices, this list of conditions,
  and the following disclaimer.  Changes or modifications
  to, or derivative works of, the Software should be noted
  with comments and the contributor and organization's
  name.
  
  2. Neither the names of UT-Battelle, LLC or the
  Department of Energy nor the names of the Software
  contributors may be used to endorse or promote products
  derived from this software without specific prior written
  permission of UT-Battelle.
  
  3. The software and the end-user documentation included
  with the redistribution, with or without modification,
  must include the following acknowledgment:
  
  "This product includes software produced by UT-Battelle,
  LLC under Contract No. DE-AC05-00OR22725  with the
  Department of Energy."
  
  *********************************************************
  DISCLAIMER
  
  THE SOFTWARE IS SUPPLIED BY THE COPYRIGHT HOLDERS AND
  CONTRIBUTORS "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 THE
  COPYRIGHT OWNER, CONTRIBUTORS, UNITED STATES GOVERNMENT,
  OR THE UNITED STATES DEPARTMENT OF ENERGY 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.
  
  NEITHER THE UNITED STATES GOVERNMENT, NOR THE UNITED
  STATES DEPARTMENT OF ENERGY, NOR THE COPYRIGHT OWNER, NOR
  ANY OF THEIR EMPLOYEES, REPRESENTS THAT THE USE OF ANY
  INFORMATION, DATA, APPARATUS, PRODUCT, OR PROCESS
  DISCLOSED WOULD NOT INFRINGE PRIVATELY OWNED RIGHTS.
  
  *********************************************************
  
  */
  /** \ingroup DMRG */
  /*@{*/
  
  /*! \file DensityMatrixBase.h
   *
   *
   *
   */
  #ifndef DENSITY_MATRIX_BASE_H
  #define DENSITY_MATRIX_BASE_H
  
  #include "BlockDiagonalMatrix.h"
  #include "PsimagLite.h"
  
  namespace Dmrg {
  template<typename TargetingType>
  class DensityMatrixBase {
  
  public:
  
  	typedef typename TargetingType::BasisWithOperatorsType BasisWithOperatorsType;
  	typedef typename BasisWithOperatorsType::BasisType BasisType;
  	typedef typename BasisWithOperatorsType::SparseMatrixType SparseMatrixType;
  	typedef typename TargetingType::TargetVectorType::value_type DensityMatrixElementType;
  	typedef typename PsimagLite::Real<DensityMatrixElementType>::Type RealType;
  	typedef typename BasisType::FactorsType FactorsType;
  	typedef typename PsimagLite::Vector<RealType>::Type VectorRealType;
  	typedef PsimagLite::Matrix<DensityMatrixElementType> MatrixType;
  	typedef BlockDiagonalMatrix<MatrixType> BlockDiagonalMatrixType;
  
  	struct Params {
  
  		Params(bool u,
  		       ProgramGlobals::DirectionEnum d,
  		       bool de,
  		       bool enablePersistentSvd_,
  		       bool serialSvd_)
  		    : useSvd(u),
  		      direction(d),
  		      debug(de),
  		      enablePersistentSvd(enablePersistentSvd_),
  		      serialSvd(serialSvd_)
  		{}
  
  		bool useSvd;
  		ProgramGlobals::DirectionEnum direction;
  		bool debug;
  		bool enablePersistentSvd;
  		bool serialSvd;
  	};
  
  	typedef typename BlockDiagonalMatrixType::BuildingBlockType BuildingBlockType;
  
  	virtual ~DensityMatrixBase()
  	{}
  
  	virtual const BlockDiagonalMatrixType& operator()()=0;
  
  	virtual void diag(typename PsimagLite::Vector<RealType>::Type&, char) = 0;
  
  	virtual const typename PsimagLite::Vector<MatrixType>::Type& vts() const
  	{
  		return vtsEmpty_;
  	}
  
  	virtual const typename PsimagLite::Vector<VectorRealType>::Type& s() const
  	{
  		return sEmpty_;
  	}
  
  	virtual const typename BasisWithOperatorsType::VectorQnType& qns() const
  	{
  		return qnsEmpty_;
  	}
  
  private:
  
  	typename PsimagLite::Vector<MatrixType>::Type vtsEmpty_;
  	typename PsimagLite::Vector<VectorRealType>::Type sEmpty_;
  	typename BasisWithOperatorsType::VectorQnType qnsEmpty_;
  
  }; // class DensityMatrixBase
  } // namespace Dmrg
  
  /*@}*/
  #endif
  
  