// Copyright (c) 1997-2007  ETH Zurich (Switzerland).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
//
// $URL: https://github.com/CGAL/cgal/blob/v5.6.1/QP_solver/include/CGAL/QP_solver/QP_partial_filtered_pricing.h $
// $Id: QP_partial_filtered_pricing.h 0779373 2020-03-26T13:31:46+01:00 Sébastien Loriot
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s)     : Sven Schoenherr
//                 Bernd Gaertner <gaertner@inf.ethz.ch>
//                 Franz Wessendorp
//                 Kaspar Fischer

#ifndef CGAL_QP_PARTIAL_FILTERED_PRICING_H
#define CGAL_QP_PARTIAL_FILTERED_PRICING_H

#include <CGAL/license/QP_solver.h>


// MSVC detection
#include <boost/config.hpp>

// includes
#include <CGAL/QP_solver/QP__partial_base.h>
#include <CGAL/QP_solver/QP__filtered_base.h>


// MSVC complains about inheritance through dominance when only one
// base implements virtual functions from the top of the diamond.
#if defined(BOOST_MSVC)
#  pragma warning(push)
#  pragma warning(disable:4250)
#endif

namespace CGAL {

// =================
// class declaration
// =================
template < typename Q, typename ET, typename Tags, class NT_ = double, class ET2NT_ =
    To_double<ET> >
class QP_partial_filtered_pricing;

// ===============
// class interface
// ===============
template < typename Q, typename ET, typename Tags, class NT_, class ET2NT_ >
class QP_partial_filtered_pricing
    : public QP__partial_base <Q,ET,Tags>,
      public QP__filtered_base<Q,ET,Tags,NT_,ET2NT_> {

    // self
    typedef  QP_pricing_strategy<Q,ET,Tags>          Base;
    typedef  QP__partial_base<Q,ET,Tags>             Partial_base;
    typedef  QP__filtered_base<Q,ET,Tags, NT_, ET2NT_>  Filtered_base;
    typedef  QP_partial_filtered_pricing<Q, ET, Tags, NT_, ET2NT_>  Self;

    // types from the base class
    typedef  typename Tags::Is_nonnegative           Is_nonnegative;
    typedef  typename Partial_base::Index_iterator        Index_iterator;
    typedef  typename Partial_base::Index_const_iterator  Index_const_iterator;

    using Base::price_dantzig;
    using Base::is_improving;

  public:

    // number type
    typedef  NT_                        NT;
    typedef  ET2NT_                     ET2NT;

    // creation
    QP_partial_filtered_pricing( bool     randomize = false,
                                  Random&  random    = get_default_random(),
                                  ET2NT    et2nt     = ET2NT());

    // operations
    int  pricing(int& direction );

    void  init( );
    void  transition( );


    // cleanup
    ~QP_partial_filtered_pricing() {};

  private:
  int pricing_helper(int& direction, Tag_true  /*is_in_standard_form*/);
  int pricing_helper(int& direction, Tag_false /*is_in_standard_form*/);
};

// ----------------------------------------------------------------------------

// =============================
// class implementation (inline)
// =============================

// construction
template < typename Q, typename ET, typename Tags, class NT_, class ET2NT_ >  inline
QP_partial_filtered_pricing<Q,ET,Tags,NT_,ET2NT_>::
QP_partial_filtered_pricing( bool randomize, Random& random, ET2NT et2nt)
    : Base( "partial filtered"),
      Partial_base( randomize, random),
      Filtered_base( et2nt)
{ }

// operations
template < typename Q, typename ET, typename Tags, class NT_, class ET2NT_ >  inline
void  QP_partial_filtered_pricing<Q,ET,Tags,NT_,ET2NT_>::
init( )
{
     Partial_base::init();
    Filtered_base::init();
}

template < typename Q, typename ET, typename Tags, class NT_, class ET2NT_ >  inline
void  QP_partial_filtered_pricing<Q,ET,Tags,NT_,ET2NT_>::
transition( )
{
     Partial_base::transition();
    Filtered_base::transition();
}


template < typename Q, typename ET, typename Tags, class NT_, class ET2NT_ >
int  QP_partial_filtered_pricing<Q,ET,Tags,NT_,ET2NT_>::
pricing(int& direction )
{
  return (pricing_helper(direction, Is_nonnegative()));
}

template < typename Q, typename ET, typename Tags, class NT_, class ET2NT_ >
int  QP_partial_filtered_pricing<Q,ET,Tags,NT_,ET2NT_>::
pricing_helper(int& /*direction*/, Tag_true /*is_in_standard_form*/ )
{
    // initialize filtered computation
    this->init_NT();

    // loop over all active non-basic variables
    CGAL_qpe_debug {
        this->vout() << "active variables:" << std::endl;
    }

    Index_const_iterator  it, min_it;
    NT                            mu, min_mu = this->nt0;
    for ( it = this->active_set_begin(); it != this->active_set_end(); ++it) {

        // don't price artificial variables
        if (this->solver().is_artificial( *it) ||
            this->solver().is_basic( *it))  // added by kf
          continue;

        // compute mu_j
        mu = this->mu_j_NT( *it);

        CGAL_qpe_debug {
            this->vout() << "  mu_" << *it << " [NT]: " << mu << std::endl;
        }

        // new minimum?
        if ( mu < min_mu) { min_it = it; min_mu = mu; }
    }

    // exact check of entering variable
    if ( min_mu < this->nt0) {
        if ( this->mu_j( *min_it) >= this->et0) {

            // exact check failed!
            CGAL_qpe_debug {
                this->vout() << "--> exact check of entering variable failed!"
                       << std::endl;
            }

            // reject entering variable
            min_mu = this->nt0;
        }
    } else {
        CGAL_qpe_debug {
            this->vout() << "--> no entering variable found yet" << std::endl;
        }
    }

    // no entering variable found so far?
    if ( ( min_mu == this->nt0) &&
         ( this->inactive_set_begin() < this->inactive_set_end())) {

        // loop over all inactive non-basic variables
        CGAL_qpe_debug {
            this->vout() << "inactive variables:" << std::endl;
        }
        Index_const_iterator  active_it;
        for ( it = this->inactive_set_begin(); it != this->inactive_set_end(); ++it) {

            // don't price artificial variables
            if (this->solver().is_artificial( *it)) continue;

            // compute mu_j
            mu = this->mu_j_NT( *it);

            CGAL_qpe_debug {
                this->vout() << "  mu_" << *it << " [NT]: " << mu << std::endl;
            }

            // candidate for entering?
            if ( mu < this->nt0) {

                // make variable active
                active_it = it;
                this->activating( active_it);

                // new minimum?
                if ( mu < min_mu) { min_it = active_it; min_mu = mu; }
            }
        }

        // exact check of entering variable
        if ( min_mu < this->nt0) {
            if ( this->mu_j( *min_it) >= this->et0) {

                // exact check failed!
                CGAL_qpe_debug {
                    this->vout() << "--> exact check of entering variable failed!"
                           << std::endl;
                }

                // reject entering variable
                min_mu = this->nt0;
            }
        } else {
            CGAL_qpe_debug {
                this->vout() << "--> still no entering variable found" << std::endl;
            }
        }
    }

    // certify non-existence of entering variable, if necessary
    if ( min_mu == this->nt0) {

        // update row and column maxima
        this->update_maxima();

        // loop over all non-basic variables again
        for ( it = this->active_set_begin(); it != this->inactive_set_end(); ++it) {

            // don't price artificial variables
            if (this->solver().is_artificial( *it)) continue;

            // certify 'mu_j >= 0'
            if ( ! this->certify_mu_j_NT( *it)) {

                // entering variable missed by inexact arithmetic
                min_it = it;
                break;
            }
        }
    }
    CGAL_qpe_debug {
      this->vout() << std::endl;
    }

    // return index of entering variable, if any
    if ( min_mu < this->nt0) {
        int  j = *min_it;
        this->entering_basis( min_it);
        return j;
    }

    // no entering variable found
    return -1;
}
template < typename Q, typename ET, typename Tags, class NT_, class ET2NT_ >
int  QP_partial_filtered_pricing<Q,ET,Tags,NT_,ET2NT_>::
pricing_helper(int& direction, Tag_false /*is_in_standard_form*/ )
{
    // initialize filtered computation
    this->init_NT();

    // loop over all active non-basic variables
    CGAL_qpe_debug {
        this->vout() << "active variables:" << std::endl;
    }

    Index_const_iterator  it, min_it;
    int min_j = -1;
    NT  mu, min_mu = this->nt0;
    for ( it = this->active_set_begin(); it != this->active_set_end(); ++it) {

        // don't price artificial variables
        if (this->solver().is_artificial( *it) ||
            this->solver().is_basic( *it))  // added by kf
          continue;

        // compute mu_j
        mu = this->mu_j_NT( *it);

        if (price_dantzig (*it, mu, this->nt0, min_j, min_mu, direction))
          min_it = it;
    }

    if ( min_j >= 0 ) {
        // exact check; do we really have an entering variable
        if ( !this->is_improving(min_j, this->mu_j( min_j), this->et0)) {

            // exact check failed!
            CGAL_qpe_debug {
                this->vout() << "--> exact check of entering variable failed!"
                       << std::endl;
            }

            // reject entering variable
            min_j = -1;
            min_mu = this->nt0;
        }
    } else {
        CGAL_qpe_debug {
            this->vout() << "--> no entering variable found yet" << std::endl;
        }
    }

    // no entering variable found so far?
    if ( ( min_j == -1) &&
         ( this->inactive_set_begin() < this->inactive_set_end())) {

        // loop over all inactive non-basic variables
        CGAL_qpe_debug {
            this->vout() << "inactive variables:" << std::endl;
        }
        Index_const_iterator  active_it;
        for ( it = this->inactive_set_begin();
              it != this->inactive_set_end(); ++it) {

            // don't price artificial variables
            if (this->solver().is_artificial( *it)) continue;

            // compute mu_j
            mu = this->mu_j_NT( *it);

            CGAL_qpe_debug {
                this->vout() << "  mu_" << *it << " [NT]: " << mu << std::endl;
            }

            // candidate for entering?
            if (is_improving(*it, mu, this->nt0)) {

                // make variable active
                active_it = it;
                this->activating( active_it);

                // new minimum
                if (price_dantzig (*active_it, mu, this->nt0,
                                    min_j, min_mu, direction))
                  min_it = active_it;
            }
        }

        if ( min_j >= 0) {
            // exact check of entering variable
            if (!this->is_improving(min_j, this->mu_j( min_j), this->et0)) {

                // exact check failed!
                CGAL_qpe_debug {
                    this->vout() <<
                      "--> exact check of entering variable failed!"
                      << std::endl;
                }

                // reject entering variable
                min_j = -1;
                min_mu = this->nt0;
            }
        } else {
            CGAL_qpe_debug {
                this->vout() <<
                  "--> still no entering variable found"
                  << std::endl;
            }
        }
    }

    // certify non-existence of entering variable, if necessary
    if ( min_j == -1) {

        // update row and column maxima
        this->update_maxima();

        // loop over all non-basic variables again
        for ( it = this->active_set_begin();
              it != this->inactive_set_end(); ++it) {

            // don't price artificial variables
            if (this->solver().is_artificial( *it)) continue;

            if ( ! this->certify_mu_j_NT( *it)) {

                // entering variable missed by inexact arithmetic
              min_j = *it;
              min_it = it;
              break;
            }
        }
    }
    CGAL_qpe_debug {
      this->vout() << std::endl;
    }

    // return index of entering variable, if any
    if ( min_j >= 0) {
      CGAL_qpe_assertion(min_j == *min_it);
      this->entering_basis( min_it);
      return min_j;
    }

    // no entering variable found
    return -1;
}

} //namespace CGAL

#if defined(BOOST_MSVC)
#  pragma warning(pop)
#endif

#endif // CGAL_QP_PARTIAL_FILTERED_PRICING_H

// ===== EOF ==================================================================

