jacobi.h

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/*
 * Copyright (c) 2010-2015:  G-CSC, Goethe University Frankfurt
 * Author: Andreas Vogel
 * 
 * This file is part of UG4.
 * 
 * UG4 is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License version 3 (as published by the
 * Free Software Foundation) with the following additional attribution
 * requirements (according to LGPL/GPL v3 §7):
 * 
 * (1) The following notice must be displayed in the Appropriate Legal Notices
 * of covered and combined works: "Based on UG4 (www.ug4.org/license)".
 * 
 * (2) The following notice must be displayed at a prominent place in the
 * terminal output of covered works: "Based on UG4 (www.ug4.org/license)".
 * 
 * (3) The following bibliography is recommended for citation and must be
 * preserved in all covered files:
 * "Reiter, S., Vogel, A., Heppner, I., Rupp, M., and Wittum, G. A massively
 *   parallel geometric multigrid solver on hierarchically distributed grids.
 *   Computing and visualization in science 16, 4 (2013), 151-164"
 * "Vogel, A., Reiter, S., Rupp, M., Nägel, A., and Wittum, G. UG4 -- a novel
 *   flexible software system for simulating pde based models on high performance
 *   computers. Computing and visualization in science 16, 4 (2013), 165-179"
 * 
 * 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 Lesser General Public License for more details.
 */
 
#ifndef __H__UG__LIB_DISC__OPERATOR__LINEAR_OPERATOR__JACOBI__
#define __H__UG__LIB_DISC__OPERATOR__LINEAR_OPERATOR__JACOBI__
 
#include "lib_algebra/operator/interface/preconditioner.h"
#include "lib_algebra/small_algebra/additional_math.h"
#include "lib_algebra/cpu_algebra/vector.h"
 
#ifdef UG_PARALLEL
  #include "lib_algebra/parallelization/parallelization.h"
#endif
 
namespace ug{
 
 
template <typename TAlgebra>
class Jacobi : public IPreconditioner<TAlgebra>
{
  public:
    typedef TAlgebra algebra_type;
 
    typedef typename TAlgebra::vector_type vector_type;
 
    typedef typename TAlgebra::matrix_type matrix_type;
 
    typedef typename IPreconditioner<TAlgebra>::matrix_operator_type matrix_operator_type;
 
    typedef IPreconditioner<TAlgebra> base_type;
 
  protected:
    using base_type::set_debug;
    using base_type::debug_writer;
    using base_type::write_debug;
    using base_type::damping;
    using base_type::approx_operator;
 
  public:
    Jacobi() {this->set_damp(1.0); m_bBlock = true;};
 
    Jacobi(number damp) {this->set_damp(damp); m_bBlock = true;};
 
    Jacobi( const Jacobi<TAlgebra> &parent )
      : base_type(parent)
    {
      set_block(parent.m_bBlock);
    }
 
    virtual SmartPtr<ILinearIterator<vector_type> > clone()
    {
      return make_sp(new Jacobi<algebra_type>(*this));
    }
 
 
    virtual bool supports_parallel() const {return true;}
 
 
    virtual ~Jacobi()
    {};
 
    void set_block(bool b)
    {
      m_bBlock = b;
    }
 
  protected:
    virtual const char* name() const {return "Jacobi";}
 
    virtual bool preprocess(SmartPtr<MatrixOperator<matrix_type, vector_type> > pOp)
    {
 
      PROFILE_BEGIN_GROUP(Jacobi_preprocess, "algebra Jacobi");
 
      matrix_type &mat = *pOp;
    //  create help vector to apply diagonal
      size_t size = mat.num_rows();
      if(size != mat.num_cols())
      {
        UG_LOG("Square Matrix needed for Jacobi Iteration.\n");
        return false;
      }
 
      //  resize
      m_diagInv.resize(size);
#ifdef UG_PARALLEL
          //  temporary vector for the diagonal
      ParallelVector<Vector< typename matrix_type::value_type > > diag;
      diag.resize(size);
 
    //  copy the layouts+communicator into the vector
      diag.set_layouts(mat.layouts());
 
    //  copy diagonal
      for(size_t i = 0; i < diag.size(); ++i){
        diag[i] = mat(i, i);
      }
 
    //  make diagonal consistent
      diag.set_storage_type(PST_ADDITIVE);
      diag.change_storage_type(PST_CONSISTENT);
 
 
      if(diag.size() > 0)
        if(CheckVectorInvertible(diag) == false)
          return false;
//      UG_ASSERT(CheckVectorInvertible(diag), "Jacobi: A has noninvertible diagonal");
 
#endif
 
//  get damping in constant case to damp at once
      number damp = 1.0;
      if(damping()->constant_damping())
        damp = damping()->damping();
 
      typename matrix_type::value_type m;
    //  invert diagonal and multiply by damping
      for(size_t i = 0; i < mat.num_rows(); ++i)
      {
#ifdef UG_PARALLEL
        typename matrix_type::value_type &d = diag[i];
#else
        typename matrix_type::value_type &d = mat(i,i);
#endif
        if(!m_bBlock)
          GetDiag(m, d);
        else
          m = d;
        m *= 1./damp;
        GetInverse(m_diagInv[i], m);
      }
 
    //  done
      return true;
    }
 
    virtual bool step(SmartPtr<MatrixOperator<matrix_type, vector_type> > pOp, vector_type& c, const vector_type& d)
    {
      PROFILE_BEGIN_GROUP(Jacobi_step, "algebra Jacobi");
 
    //  multiply defect with diagonal, c = damp * D^{-1} * d
    //  note, that the damping is already included in the inverse diagonal
      for(size_t i = 0; i < m_diagInv.size(); ++i)
      {
      //  c[i] = m_diagInv[i] * d[i];
        MatMult(c[i], 1.0, m_diagInv[i], d[i]);
      }
 
#ifdef UG_PARALLEL
 
    //  the computed correction is additive
      c.set_storage_type(PST_ADDITIVE);
 
    //  we make it consistent
      if(!c.change_storage_type(PST_CONSISTENT))
      {
        UG_LOG("ERROR in 'JacobiPreconditioner::apply': "
            "Cannot change parallel status of correction to consistent.\n");
        return false;
      }
#endif
    //  done
      return true;
    }
 
    virtual bool postprocess() {return true;}
 
 
  //  overwrite function in order to specially treat constant damping
    virtual bool apply(vector_type& c, const vector_type& d)
    {
      PROFILE_BEGIN_GROUP(Jacobi_apply, "algebra Jacobi");
    //  Check that operator is initialized
      if(!this->m_bInit)
      {
        UG_LOG("ERROR in '"<<name()<<"::apply': Iterator not initialized.\n");
        return false;
      }
 
    //  Check parallel status
      #ifdef UG_PARALLEL
      if(!d.has_storage_type(PST_ADDITIVE))
        UG_THROW(name() << "::apply: Wrong parallel "
                       "storage format. Defect must be additive.");
      #endif
 
    //  Check sizes
      THROW_IF_NOT_EQUAL_4(c.size(), d.size(), approx_operator()->num_rows(), approx_operator()->num_cols());
 
    //  apply iterator: c = B*d
      if(!step(approx_operator(), c, d))
      {
        UG_LOG("ERROR in '"<<name()<<"::apply': Step Routine failed.\n");
        return false;
      }
 
    //  apply scaling
      if(!damping()->constant_damping()){
        const number kappa = damping()->damping(c, d, approx_operator());
        if(kappa != 1.0){
          c *= kappa;
        }
      }
 
    //  Correction is always consistent
      #ifdef  UG_PARALLEL
      if(!c.change_storage_type(PST_CONSISTENT))
        UG_THROW(name() << "::apply': Cannot change "
            "parallel storage type of correction to consistent.");
      #endif
 
    //  we're done
      return true;
    }
 
  protected:
    typedef typename block_traits<typename matrix_type::value_type>::inverse_type inverse_type;
 
    std::vector<inverse_type> m_diagInv;
    bool m_bBlock;
 
 
};
 
} // end namespace ug
 
//#include "gpujacobi.h"
 
#endif