RhodeCode

    messageLevel(MESSAGE_NO_OUTPUT);

  }

  ClpLp::ClpLp(const ClpLp& other) {

    _prob = new ClpSimplex(*other._prob);

    rows = other.rows;

    cols = other.cols;

    _init_temporals();

    messageLevel(MESSAGE_NO_OUTPUT);

  }

  ClpLp::~ClpLp() {

    delete _prob;

    _clear_temporals();

  }

  void ClpLp::_init_temporals() {

    _primal_ray = 0;

    _dual_ray = 0;

  }

  void ClpLp::_clear_temporals() {

    if (_primal_ray) {

      delete[] _primal_ray;

      _primal_ray = 0;

    }

    if (_dual_ray) {

      delete[] _dual_ray;

      _dual_ray = 0;

    }

  }

    ClpLp* newlp = new ClpLp;

    return newlp;

  }

    ClpLp* copylp = new ClpLp(*this);

    return copylp;

  }

  const char* ClpLp::_solverName() const { return "ClpLp"; }

  int ClpLp::_addCol() {

    _prob->addColumn(0, 0, 0, -COIN_DBL_MAX, COIN_DBL_MAX, 0.0);

    return _prob->numberColumns() - 1;

  }

  int ClpLp::_addRow() {

    _prob->addRow(0, 0, 0, -COIN_DBL_MAX, COIN_DBL_MAX);

    return _prob->numberRows() - 1;

  }

  void ClpLp::_eraseCol(int c) {

    _col_names_ref.erase(_prob->getColumnName(c));

    _prob->deleteColumns(1, &c);

  }

  void ClpLp::_eraseRow(int r) {

    _row_names_ref.erase(_prob->getRowName(r));

    _prob->deleteRows(1, &r);

  }

  void ClpLp::_eraseColId(int i) {

    cols.eraseIndex(i);

    cols.shiftIndices(i);

  }

#include <lemon/lp_base.h>

class ClpSimplex;

namespace lemon {

  /// \ingroup lp_group

  ///

  /// \brief Interface for the CLP solver

  ///

  /// This class implements an interface for the Clp LP solver.  The

  /// Clp library is an object oriented lp solver library developed at

  /// the IBM. The CLP is part of the COIN-OR package and it can be

  /// used with Common Public License.

  class ClpLp : public LpSolver {

  protected:

    ClpSimplex* _prob;

    std::map<std::string, int> _col_names_ref;

    std::map<std::string, int> _row_names_ref;

  public:

    /// \e

    ClpLp();

    /// \e

    ClpLp(const ClpLp&);

    /// \e

    ~ClpLp();

  protected:

    mutable double* _primal_ray;

    mutable double* _dual_ray;

    void _init_temporals();

    void _clear_temporals();

  protected:

    virtual const char* _solverName() const;

    virtual int _addCol();

    virtual int _addRow();

    virtual void _eraseCol(int i);

    virtual void _eraseRow(int i);

    virtual void _eraseColId(int i);

    virtual void _eraseRowId(int i);

    virtual void _getColName(int col, std::string& name) const;

    virtual void _setColName(int col, const std::string& name);

    virtual int _colByName(const std::string& name) const;

    virtual void _getRowName(int row, std::string& name) const;

    virtual void _setRowName(int row, const std::string& name);

    virtual int _rowByName(const std::string& name) const;

    virtual void _setRowCoeffs(int i, ExprIterator b, ExprIterator e);

    virtual void _getRowCoeffs(int i, InsertIterator b) const;

    virtual void _setColCoeffs(int i, ExprIterator b, ExprIterator e);

    virtual void _getColCoeffs(int i, InsertIterator b) const;

    virtual void _setCoeff(int row, int col, Value value);

    virtual Value _getCoeff(int row, int col) const;

    virtual void _setColLowerBound(int i, Value value);

    virtual Value _getColLowerBound(int i) const;

    virtual void _setColUpperBound(int i, Value value);

    virtual Value _getColUpperBound(int i) const;

    switch (CPXgetobjsen(cplexEnv(), _prob)) {

    case CPX_MIN:

      return MIN;

    case CPX_MAX:

      return MAX;

    default:

      LEMON_ASSERT(false, "Invalid sense");

      return CplexBase::Sense();

    }

  }

  void CplexBase::_clear() {

    CPXfreeprob(cplexEnv(),&_prob);

    int status;

    _prob = CPXcreateprob(cplexEnv(), &status, "Cplex problem");

    rows.clear();

    cols.clear();

  }

  // CplexLp members

  CplexLp::CplexLp()

    : LpBase(), CplexBase(), LpSolver() {}

  CplexLp::CplexLp(const CplexEnv& env)

    : LpBase(), CplexBase(env), LpSolver() {}

  CplexLp::CplexLp(const CplexLp& other)

    : LpBase(), CplexBase(other), LpSolver() {}

  CplexLp::~CplexLp() {}

  const char* CplexLp::_solverName() const { return "CplexLp"; }

  void CplexLp::_clear_temporals() {

    _col_status.clear();

    _row_status.clear();

    _primal_ray.clear();

    _dual_ray.clear();

  }

  // The routine returns zero unless an error occurred during the

  // optimization. Examples of errors include exhausting available

  // memory (CPXERR_NO_MEMORY) or encountering invalid data in the

  // CPLEX problem object (CPXERR_NO_PROBLEM). Exceeding a

  // user-specified CPLEX limit, or proving the model infeasible or

  // unbounded, are not considered errors. Note that a zero return

  // value does not necessarily mean that a solution exists. Use query

  // routines CPXsolninfo, CPXgetstat, and CPXsolution to obtain

  // further information about the status of the optimization.

  CplexLp::SolveExitStatus CplexLp::convertStatus(int status) {

#if CPX_VERSION >= 800

    if (status == 0) {

      switch (CPXgetstat(cplexEnv(), _prob)) {

      case CPX_STAT_OPTIMAL:

      case CPX_STAT_INFEASIBLE:

      case CPX_STAT_UNBOUNDED:

        return SOLVED;

      default:

        return UNSOLVED;

      }

    } else {

      return UNSOLVED;

    }

#endif

  }

  // CplexMip members

  CplexMip::CplexMip()

    : LpBase(), CplexBase(), MipSolver() {

#if CPX_VERSION < 800

    CPXchgprobtype(cplexEnv(),  _prob, CPXPROB_MIP);

#else

    CPXchgprobtype(cplexEnv(),  _prob, CPXPROB_MILP);

#endif

  }

  CplexMip::CplexMip(const CplexEnv& env)

    : LpBase(), CplexBase(env), MipSolver() {

#if CPX_VERSION < 800

    CPXchgprobtype(cplexEnv(),  _prob, CPXPROB_MIP);

#else

    CPXchgprobtype(cplexEnv(),  _prob, CPXPROB_MILP);

#endif

  }

  CplexMip::CplexMip(const CplexMip& other)

    : LpBase(), CplexBase(other), MipSolver() {}

  CplexMip::~CplexMip() {}

  const char* CplexMip::_solverName() const { return "CplexMip"; }

  void CplexMip::_setColType(int i, CplexMip::ColTypes col_type) {

    // Note If a variable is to be changed to binary, a call to CPXchgbds

    // should also be made to change the bounds to 0 and 1.

    switch (col_type){

    case INTEGER: {

      const char t = 'I';

      CPXchgctype (cplexEnv(), _prob, 1, &i, &t);

    } break;

    case REAL: {

      const char t = 'C';

      CPXchgctype (cplexEnv(), _prob, 1, &i, &t);

    } break;

    default:

      break;

    }

  }

  CplexMip::ColTypes CplexMip::_getColType(int i) const {

    char t;

    CPXgetctype (cplexEnv(), _prob, &t, i, i);

    switch (t) {

    case 'I':

      return INTEGER;

    case 'C':

      return REAL;

    default:

      LEMON_ASSERT(false, "Invalid column type");

    virtual Value _getRowLowerBound(int i) const;

    virtual void _setRowUpperBound(int i, Value value);

    virtual Value _getRowUpperBound(int i) const;

    virtual void _setObjCoeffs(ExprIterator b, ExprIterator e);

    virtual void _getObjCoeffs(InsertIterator b) const;

    virtual void _setObjCoeff(int i, Value obj_coef);

    virtual Value _getObjCoeff(int i) const;

    virtual void _setSense(Sense sense);

    virtual Sense _getSense() const;

    virtual void _clear();

  public:

    /// Returns the used \c CplexEnv instance

    const CplexEnv& env() const { return _env; }

    ///

    const cpxenv* cplexEnv() const { return _env.cplexEnv(); }

    cpxlp* cplexLp() { return _prob; }

    const cpxlp* cplexLp() const { return _prob; }

  };

  /// \brief Interface for the CPLEX LP solver

  ///

  /// This class implements an interface for the CPLEX LP solver.

  ///\ingroup lp_group

  public:

    /// \e

    CplexLp();

    /// \e

    CplexLp(const CplexEnv&);

    /// \e

    CplexLp(const CplexLp&);

    /// \e

    virtual ~CplexLp();

  private:

    // these values cannot retrieved element by element

    mutable std::vector<int> _col_status;

    mutable std::vector<int> _row_status;

    mutable std::vector<Value> _primal_ray;

    mutable std::vector<Value> _dual_ray;

    void _clear_temporals();

    SolveExitStatus convertStatus(int status);

  protected:

    virtual const char* _solverName() const;

    virtual SolveExitStatus _solve();

    virtual Value _getPrimal(int i) const;

    virtual Value _getDual(int i) const;

    virtual Value _getPrimalValue() const;

    virtual VarStatus _getColStatus(int i) const;

    virtual VarStatus _getRowStatus(int i) const;

    virtual Value _getPrimalRay(int i) const;

    virtual Value _getDualRay(int i) const;

    virtual ProblemType _getPrimalType() const;

    virtual ProblemType _getDualType() const;

  public:

    /// Solve with primal simplex method

    SolveExitStatus solvePrimal();

    /// Solve with dual simplex method

    SolveExitStatus solveDual();

    /// Solve with barrier method

    SolveExitStatus solveBarrier();

  };

  /// \brief Interface for the CPLEX MIP solver

  ///

  /// This class implements an interface for the CPLEX MIP solver.

  ///\ingroup lp_group

  public:

    /// \e

    CplexMip();

    /// \e

    CplexMip(const CplexEnv&);

    /// \e

    CplexMip(const CplexMip&);

    /// \e

    virtual ~CplexMip();

  protected:

    virtual CplexMip* _cloneSolver() const;

    virtual CplexMip* _newSolver() const;

    virtual const char* _solverName() const;

    virtual ColTypes _getColType(int col) const;

    virtual void _setColType(int col, ColTypes col_type);

    virtual SolveExitStatus _solve();

    virtual ProblemType _getType() const;

    virtual Value _getSol(int i) const;

    virtual Value _getSolValue() const;

  };

} //END OF NAMESPACE LEMON

#endif //LEMON_CPLEX_H

  }

  GlpkBase::Sense GlpkBase::_getSense() const {

    switch(glp_get_obj_dir(lp)) {

    case GLP_MIN:

      return MIN;

    case GLP_MAX:

      return MAX;

    default:

      LEMON_ASSERT(false, "Wrong sense");

      return GlpkBase::Sense();

    }

  }

  void GlpkBase::_clear() {

    glp_erase_prob(lp);

    rows.clear();

    cols.clear();

  }

  // GlpkLp members

  GlpkLp::GlpkLp()

    : LpBase(), GlpkBase(), LpSolver() {

    messageLevel(MESSAGE_NO_OUTPUT);

  }

  GlpkLp::GlpkLp(const GlpkLp& other)

    : LpBase(other), GlpkBase(other), LpSolver(other) {

    messageLevel(MESSAGE_NO_OUTPUT);

  }

  const char* GlpkLp::_solverName() const { return "GlpkLp"; }

  void GlpkLp::_clear_temporals() {

    _primal_ray.clear();

    _dual_ray.clear();

  }

  GlpkLp::SolveExitStatus GlpkLp::_solve() {

    return solvePrimal();

  }

  GlpkLp::SolveExitStatus GlpkLp::solvePrimal() {

    _clear_temporals();

    glp_smcp smcp;

    glp_init_smcp(&smcp);

    switch (_message_level) {

    case MESSAGE_NO_OUTPUT:

      smcp.msg_lev = GLP_MSG_OFF;

      break;

    case MESSAGE_ERROR_MESSAGE:

      smcp.msg_lev = GLP_MSG_ERR;

      break;

    case MESSAGE_NORMAL_OUTPUT:

      smcp.msg_lev = GLP_MSG_ON;

      break;

    case MESSAGE_FULL_OUTPUT:

      smcp.msg_lev = GLP_MSG_ALL;

      break;

    }

        return INFEASIBLE;

      case GLP_FEAS:

        return FEASIBLE;

      case GLP_OPT:

        return OPTIMAL;

      default:

        LEMON_ASSERT(false, "Wrong problem type.");

        return GlpkMip::ProblemType();

      }

    case GLP_NOFEAS:

      return INFEASIBLE;

    case GLP_INFEAS:

    case GLP_FEAS:

      if (glp_get_dual_stat(lp) == GLP_NOFEAS) {

        return UNBOUNDED;

      } else {

        return UNDEFINED;

      }

    default:

      LEMON_ASSERT(false, "Wrong problem type.");

      return GlpkMip::ProblemType();

    }

  }

  GlpkMip::Value GlpkMip::_getSol(int i) const {

    return glp_mip_col_val(lp, i);

  }

  GlpkMip::Value GlpkMip::_getSolValue() const {

    return glp_mip_obj_val(lp);

  }

  const char* GlpkMip::_solverName() const { return "GlpkMip"; }

  void GlpkMip::messageLevel(MessageLevel m) {

    _message_level = m;

  }

} //END OF NAMESPACE LEMON

    virtual Value _getRowUpperBound(int i) const;

    virtual void _setObjCoeffs(ExprIterator b, ExprIterator e);

    virtual void _getObjCoeffs(InsertIterator b) const;

    virtual void _setObjCoeff(int i, Value obj_coef);

    virtual Value _getObjCoeff(int i) const;

    virtual void _setSense(Sense);

    virtual Sense _getSense() const;

    virtual void _clear();

  public:

    ///Pointer to the underlying GLPK data structure.

    LPX *lpx() {return lp;}

    ///Const pointer to the underlying GLPK data structure.

    const LPX *lpx() const {return lp;}

    ///Returns the constraint identifier understood by GLPK.

    int lpxRow(Row r) const { return rows(id(r)); }

    ///Returns the variable identifier understood by GLPK.

    int lpxCol(Col c) const { return cols(id(c)); }

  };

  /// \brief Interface for the GLPK LP solver

  ///

  /// This class implements an interface for the GLPK LP solver.

  ///\ingroup lp_group

  public:

    ///\e

    GlpkLp();

    ///\e

    GlpkLp(const GlpkLp&);

  private:

    mutable std::vector<double> _primal_ray;

    mutable std::vector<double> _dual_ray;

    void _clear_temporals();

  protected:

    virtual const char* _solverName() const;

    virtual SolveExitStatus _solve();

    virtual Value _getPrimal(int i) const;

    virtual Value _getDual(int i) const;

    virtual Value _getPrimalValue() const;

    virtual VarStatus _getColStatus(int i) const;

    virtual VarStatus _getRowStatus(int i) const;

    virtual Value _getPrimalRay(int i) const;

    virtual Value _getDualRay(int i) const;

    ///\todo It should be clarified

    ///

    virtual ProblemType _getPrimalType() const;

    virtual ProblemType _getDualType() const;

  public:

    ///Solve with primal simplex

    SolveExitStatus solvePrimal();

    ///Solve with dual simplex

    SolveExitStatus solveDual();

    ///Turns on or off the presolver

    ///Turns on (\c b is \c true) or off (\c b is \c false) the presolver

    ///

    ///The presolver is off by default.

    void presolver(bool b);

    ///Enum for \c messageLevel() parameter

    enum MessageLevel {

      /// no output (default value)

      MESSAGE_NO_OUTPUT = 0,

      /// error messages only

      MESSAGE_ERROR_MESSAGE = 1,

      /// normal output

      MESSAGE_NORMAL_OUTPUT = 2,

      /// full output (includes informational messages)

      MESSAGE_FULL_OUTPUT = 3

    };

  private:

    MessageLevel _message_level;

  public:

    ///Set the verbosity of the messages

    ///Set the verbosity of the messages

    ///

    ///\param m is the level of the messages output by the solver routines.

    void messageLevel(MessageLevel m);

  };

  /// \brief Interface for the GLPK MIP solver

  ///

  /// This class implements an interface for the GLPK MIP solver.

  ///\ingroup lp_group

  public:

    ///\e

    GlpkMip();

    ///\e

    GlpkMip(const GlpkMip&);

  protected:

    virtual const char* _solverName() const;

    virtual ColTypes _getColType(int col) const;

    virtual void _setColType(int col, ColTypes col_type);

    virtual SolveExitStatus _solve();

    virtual ProblemType _getType() const;

    virtual Value _getSol(int i) const;

    virtual Value _getSolValue() const;

    ///Enum for \c messageLevel() parameter

    enum MessageLevel {

      /// no output (default value)

      MESSAGE_NO_OUTPUT = 0,

      /// error messages only

      MESSAGE_ERROR_MESSAGE = 1,

      /// normal output

      MESSAGE_NORMAL_OUTPUT = 2,

      /// full output (includes informational messages)

      MESSAGE_FULL_OUTPUT = 3

    };

  private:

    MessageLevel _message_level;

  public:

    ///Set the verbosity of the messages

    ///Set the verbosity of the messages

    ///

      reference operator*() {

        return std::make_pair(_index(_host_it->first), _host_it->second);

      }

      pointer operator->() {

        return pointer(operator*());

      }

      ExprIterator& operator++() { ++_host_it; return *this; }

      ExprIterator operator++(int) {

        ExprIterator tmp(*this); ++_host_it; return tmp;

      }

      ExprIterator& operator--() { --_host_it; return *this; }

      ExprIterator operator--(int) {

        ExprIterator tmp(*this); --_host_it; return tmp;

      }

      bool operator==(const ExprIterator& it) const {

        return _host_it == it._host_it;

      }

      bool operator!=(const ExprIterator& it) const {

        return _host_it != it._host_it;

      }

    };

  protected:

    //Abstract virtual functions

    virtual int _addColId(int col) { return cols.addIndex(col); }

    virtual int _addRowId(int row) { return rows.addIndex(row); }

    virtual void _eraseColId(int col) { cols.eraseIndex(col); }

    virtual void _eraseRowId(int row) { rows.eraseIndex(row); }

    virtual int _addCol() = 0;

    virtual int _addRow() = 0;

    virtual void _eraseCol(int col) = 0;

    virtual void _eraseRow(int row) = 0;

    virtual void _getColName(int col, std::string& name) const = 0;

    virtual void _setColName(int col, const std::string& name) = 0;

    virtual int _colByName(const std::string& name) const = 0;

    virtual void _getRowName(int row, std::string& name) const = 0;

    virtual void _setRowName(int row, const std::string& name) = 0;

    virtual int _rowByName(const std::string& name) const = 0;

    virtual void _setRowCoeffs(int i, ExprIterator b, ExprIterator e) = 0;

    virtual void _getRowCoeffs(int i, InsertIterator b) const = 0;

    virtual void _setColCoeffs(int i, ExprIterator b, ExprIterator e) = 0;

    virtual void _getColCoeffs(int i, InsertIterator b) const = 0;

    virtual void _setCoeff(int row, int col, Value value) = 0;

    virtual Value _getCoeff(int row, int col) const = 0;

    virtual void _setColLowerBound(int i, Value value) = 0;

    virtual Value _getColLowerBound(int i) const = 0;

    virtual void _setRowLowerBound(int i, Value value) = 0;

    virtual Value _getRowLowerBound(int i) const = 0;

    virtual void _setRowUpperBound(int i, Value value) = 0;

    virtual Value _getRowUpperBound(int i) const = 0;

    virtual void _setObjCoeffs(ExprIterator b, ExprIterator e) = 0;

    virtual void _getObjCoeffs(InsertIterator b) const = 0;

    virtual void _setObjCoeff(int i, Value obj_coef) = 0;

    virtual Value _getObjCoeff(int i) const = 0;

    virtual void _setSense(Sense) = 0;

    virtual Sense _getSense() const = 0;

    virtual void _clear() = 0;

    virtual const char* _solverName() const = 0;

    //Own protected stuff

    //Constant component of the objective function

    Value obj_const_comp;

    LpBase() : rows(), cols(), obj_const_comp(0) {}

  public:

    /// Virtual destructor

    virtual ~LpBase() {}

    ///Gives back the name of the solver.

    const char* solverName() const {return _solverName();}

    ///\name Build up and modify the LP

    ///@{

    ///Add a new empty column (i.e a new variable) to the LP

    Col addCol() { Col c; c._id = _addColId(_addCol()); return c;}

    ///\brief Adds several new columns (i.e variables) at once

    ///

    ///This magic function takes a container as its argument and fills

    ///its elements with new columns (i.e. variables)

    ///\param t can be

    ///- a standard STL compatible iterable container with

    ///\ref Col as its \c values_type like

    ///\code

    ///std::vector<LpBase::Col>

    ///std::list<LpBase::Col>

    ///\endcode

    ///- a standard STL compatible iterable container with

    ///\ref Col as its \c mapped_type like

    ///\code

    ///std::map<AnyType,LpBase::Col>

    ///\endcode

    ///- an iterable lemon \ref concepts::WriteMap "write map" like

    ///\code

    ///ListGraph::NodeMap<LpBase::Col>

    ///ListGraph::ArcMap<LpBase::Col>

    ///\endcode

    ///\return The number of the created column.

      /// The variable is in the basis

      BASIC, 

      /// The variable is free, but not basic

      FREE,

      /// The variable has active lower bound 

      LOWER,

      /// The variable has active upper bound

      UPPER,

      /// The variable is non-basic and fixed

      FIXED

    };

  protected:

    virtual SolveExitStatus _solve() = 0;

    virtual Value _getPrimal(int i) const = 0;

    virtual Value _getDual(int i) const = 0;

    virtual Value _getPrimalRay(int i) const = 0;

    virtual Value _getDualRay(int i) const = 0;

    virtual Value _getPrimalValue() const = 0;

    virtual VarStatus _getColStatus(int i) const = 0;

    virtual VarStatus _getRowStatus(int i) const = 0;

    virtual ProblemType _getPrimalType() const = 0;

    virtual ProblemType _getDualType() const = 0;

  public:

    ///\name Solve the LP

    ///@{

    ///\e Solve the LP problem at hand

    ///

    ///\return The result of the optimization procedure. Possible

    ///values and their meanings can be found in the documentation of

    ///\ref SolveExitStatus.

    SolveExitStatus solve() { return _solve(); }

    ///@}

    ///\name Obtain the solution

    ///@{

    /// The type of the primal problem

    ProblemType primalType() const {

      return _getPrimalType();

    }

    /// The type of the dual problem

    ProblemType dualType() const {

      return _getDualType();

    }

    /// Return the primal value of the column

    /// Return the primal value of the column.

    /// \pre The problem is solved.

    Value primal(Col c) const { return _getPrimal(cols(id(c))); }

    /// we change each finite bound to 0 (i.e. the objective function

    /// coefficients in the primal problem), and we looking for a

    /// ositive objective value. If there is such solution, that

    /// proofs the unsolvability of the primal problem, and if a

    /// feasible dual solution exists, then the unboundness of

    /// dual problem.

    ///

    /// \pre The problem is solved and the primal problem is infeasible.

    /// \note Some solvers does not provide dual ray calculation

    /// functions.

    Value dualRay(Row r) const { return _getDualRay(rows(id(r))); }

    /// Return the basis status of the column

    /// \see VarStatus

    VarStatus colStatus(Col c) const { return _getColStatus(cols(id(c))); }

    /// Return the basis status of the row

    /// \see VarStatus

    VarStatus rowStatus(Row r) const { return _getRowStatus(rows(id(r))); }

    ///The value of the objective function

    ///\return

    ///- \ref INF or -\ref INF means either infeasibility or unboundedness

    /// of the primal problem, depending on whether we minimize or maximize.

    ///- \ref NaN if no primal solution is found.

    ///- The (finite) objective value if an optimal solution is found.

    Value primal() const { return _getPrimalValue()+obj_const_comp;}

    ///@}

  protected:

  };

  /// \ingroup lp_group

  ///

  /// \brief Common base class for MIP solvers

  ///

  /// This class is an abstract base class for MIP solvers. This class

  /// provides a full interface for set and modify an MIP problem,

  /// solve it and retrieve the solution. You can use one of the

  /// descendants as a concrete implementation, or the \c Lp

  /// default MIP solver. However, if you would like to handle MIP

  /// solvers as reference or pointer in a generic way, you can use

  /// this class directly.

  class MipSolver : virtual public LpBase {

  public:

    /// The problem types for MIP problems

    enum ProblemType {

      ///Feasible solution hasn't been found (but may exist).

      UNDEFINED = 0,

      ///The problem has no feasible solution

      INFEASIBLE = 1,

      ///Feasible solution found

      FEASIBLE = 2,

      ///Optimal solution exists and found

      OPTIMAL = 3,

      ///The cost function is unbounded

      ///

      ///The Mip or at least the relaxed problem is unbounded

      UNBOUNDED = 4

    };

    ///\name Solve the MIP

    ///@{

    /// Solve the MIP problem at hand

    ///

    ///\return The result of the optimization procedure. Possible

    ///values and their meanings can be found in the documentation of

    ///\ref SolveExitStatus.

    SolveExitStatus solve() { return _solve(); }

    ///@}

    ///\name Setting column type

    ///@{

    ///Possible variable (column) types (e.g. real, integer, binary etc.)

    enum ColTypes {

      ///Continuous variable (default)

      REAL = 0,

      ///Integer variable

      INTEGER = 1

    };

    ///Sets the type of the given column to the given type

    ///Sets the type of the given column to the given type.

    ///

    void colType(Col c, ColTypes col_type) {

      _setColType(cols(id(c)),col_type);

    }

    /// Return the value of the expression in the solution

    /// Return the value of the expression in the solution, i.e. the

    /// dot product of the solution and the expression.

    /// \pre The problem is solved.

    Value sol(const Expr& e) const {

      double res = *e;

      for (Expr::ConstCoeffIt c(e); c != INVALID; ++c) {

        res += *c * sol(c);

      }

      return res;

    }

    ///The value of the objective function

    ///\return

    ///- \ref INF or -\ref INF means either infeasibility or unboundedness

    /// of the problem, depending on whether we minimize or maximize.

    ///- \ref NaN if no primal solution is found.

    ///- The (finite) objective value if an optimal solution is found.

    Value solValue() const { return _getSolValue()+obj_const_comp;}

    ///@}

  protected:

    virtual SolveExitStatus _solve() = 0;

    virtual ColTypes _getColType(int col) const = 0;

    virtual void _setColType(int col, ColTypes col_type) = 0;

    virtual ProblemType _getType() const = 0;

    virtual Value _getSol(int i) const = 0;

    virtual Value _getSolValue() const = 0;

  };

} //namespace lemon

#endif //LEMON_LP_BASE_H