lemon/lp_skeleton.cc
author Peter Kovacs <kpeter@inf.elte.hu>
Tue, 15 Mar 2011 19:32:21 +0100
changeset 936 ddd3c0d3d9bf
parent 746 e4554cd6b2bf
child 1063 1782aa72495a
permissions -rw-r--r--
Implement the scaling Price Refinement heuristic in CostScaling (#417)
instead of Early Termination.

These two heuristics are similar, but the newer one is faster
and not only makes it possible to skip some epsilon phases, but
it can improve the performance of the other phases, as well.
     1 /* -*- mode: C++; indent-tabs-mode: nil; -*-
     2  *
     3  * This file is a part of LEMON, a generic C++ optimization library.
     4  *
     5  * Copyright (C) 2003-2010
     6  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
     7  * (Egervary Research Group on Combinatorial Optimization, EGRES).
     8  *
     9  * Permission to use, modify and distribute this software is granted
    10  * provided that this copyright notice appears in all copies. For
    11  * precise terms see the accompanying LICENSE file.
    12  *
    13  * This software is provided "AS IS" with no warranty of any kind,
    14  * express or implied, and with no claim as to its suitability for any
    15  * purpose.
    16  *
    17  */
    18 
    19 #include <lemon/lp_skeleton.h>
    20 
    21 ///\file
    22 ///\brief A skeleton file to implement LP solver interfaces
    23 namespace lemon {
    24 
    25   int SkeletonSolverBase::_addCol()
    26   {
    27     return ++col_num;
    28   }
    29 
    30   int SkeletonSolverBase::_addRow()
    31   {
    32     return ++row_num;
    33   }
    34 
    35   int SkeletonSolverBase::_addRow(Value, ExprIterator, ExprIterator, Value)
    36   {
    37     return ++row_num;
    38   }
    39 
    40   void SkeletonSolverBase::_eraseCol(int) {}
    41   void SkeletonSolverBase::_eraseRow(int) {}
    42 
    43   void SkeletonSolverBase::_getColName(int, std::string &) const {}
    44   void SkeletonSolverBase::_setColName(int, const std::string &) {}
    45   int SkeletonSolverBase::_colByName(const std::string&) const { return -1; }
    46 
    47   void SkeletonSolverBase::_getRowName(int, std::string &) const {}
    48   void SkeletonSolverBase::_setRowName(int, const std::string &) {}
    49   int SkeletonSolverBase::_rowByName(const std::string&) const { return -1; }
    50 
    51   void SkeletonSolverBase::_setRowCoeffs(int, ExprIterator, ExprIterator) {}
    52   void SkeletonSolverBase::_getRowCoeffs(int, InsertIterator) const {}
    53 
    54   void SkeletonSolverBase::_setColCoeffs(int, ExprIterator, ExprIterator) {}
    55   void SkeletonSolverBase::_getColCoeffs(int, InsertIterator) const {}
    56 
    57   void SkeletonSolverBase::_setCoeff(int, int, Value) {}
    58   SkeletonSolverBase::Value SkeletonSolverBase::_getCoeff(int, int) const
    59   { return 0; }
    60 
    61   void SkeletonSolverBase::_setColLowerBound(int, Value) {}
    62   SkeletonSolverBase::Value SkeletonSolverBase::_getColLowerBound(int) const
    63   {  return 0; }
    64 
    65   void SkeletonSolverBase::_setColUpperBound(int, Value) {}
    66   SkeletonSolverBase::Value SkeletonSolverBase::_getColUpperBound(int) const
    67   {  return 0; }
    68 
    69   void SkeletonSolverBase::_setRowLowerBound(int, Value) {}
    70   SkeletonSolverBase::Value SkeletonSolverBase::_getRowLowerBound(int) const
    71   {  return 0; }
    72 
    73   void SkeletonSolverBase::_setRowUpperBound(int, Value) {}
    74   SkeletonSolverBase::Value SkeletonSolverBase::_getRowUpperBound(int) const
    75   {  return 0; }
    76 
    77   void SkeletonSolverBase::_setObjCoeffs(ExprIterator, ExprIterator) {}
    78   void SkeletonSolverBase::_getObjCoeffs(InsertIterator) const {};
    79 
    80   void SkeletonSolverBase::_setObjCoeff(int, Value) {}
    81   SkeletonSolverBase::Value SkeletonSolverBase::_getObjCoeff(int) const
    82   {  return 0; }
    83 
    84   void SkeletonSolverBase::_setSense(Sense) {}
    85   SkeletonSolverBase::Sense SkeletonSolverBase::_getSense() const
    86   { return MIN; }
    87 
    88   void SkeletonSolverBase::_clear() {
    89     row_num = col_num = 0;
    90   }
    91 
    92   void SkeletonSolverBase::_messageLevel(MessageLevel) {}
    93 
    94   LpSkeleton::SolveExitStatus LpSkeleton::_solve() { return SOLVED; }
    95 
    96   LpSkeleton::Value LpSkeleton::_getPrimal(int) const { return 0; }
    97   LpSkeleton::Value LpSkeleton::_getDual(int) const { return 0; }
    98   LpSkeleton::Value LpSkeleton::_getPrimalValue() const { return 0; }
    99 
   100   LpSkeleton::Value LpSkeleton::_getPrimalRay(int) const { return 0; }
   101   LpSkeleton::Value LpSkeleton::_getDualRay(int) const { return 0; }
   102 
   103   LpSkeleton::ProblemType LpSkeleton::_getPrimalType() const
   104   { return UNDEFINED; }
   105 
   106   LpSkeleton::ProblemType LpSkeleton::_getDualType() const
   107   { return UNDEFINED; }
   108 
   109   LpSkeleton::VarStatus LpSkeleton::_getColStatus(int) const
   110   { return BASIC; }
   111 
   112   LpSkeleton::VarStatus LpSkeleton::_getRowStatus(int) const
   113   { return BASIC; }
   114 
   115   LpSkeleton* LpSkeleton::newSolver() const
   116   { return static_cast<LpSkeleton*>(0); }
   117 
   118   LpSkeleton* LpSkeleton::cloneSolver() const
   119   { return static_cast<LpSkeleton*>(0); }
   120 
   121   const char* LpSkeleton::_solverName() const { return "LpSkeleton"; }
   122 
   123   MipSkeleton::SolveExitStatus MipSkeleton::_solve()
   124   { return SOLVED; }
   125 
   126   MipSkeleton::Value MipSkeleton::_getSol(int) const { return 0; }
   127   MipSkeleton::Value MipSkeleton::_getSolValue() const { return 0; }
   128 
   129   MipSkeleton::ProblemType MipSkeleton::_getType() const
   130   { return UNDEFINED; }
   131 
   132   MipSkeleton* MipSkeleton::newSolver() const
   133   { return static_cast<MipSkeleton*>(0); }
   134 
   135   MipSkeleton* MipSkeleton::cloneSolver() const
   136   { return static_cast<MipSkeleton*>(0); }
   137 
   138   const char* MipSkeleton::_solverName() const { return "MipSkeleton"; }
   139 
   140 } //namespace lemon
   141