clsvar_gamssymbol.cpp

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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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/*                  This file is part of the program                         */
/*          GCG --- Generic Column Generation                                */
/*                  a Dantzig-Wolfe decomposition based extension            */
/*                  of the branch-cut-and-price framework                    */
/*         SCIP --- Solving Constraint Integer Programs                      */
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/* Copyright (C) 2010-2021 Operations Research, RWTH Aachen University       */
/*                         Zuse Institute Berlin (ZIB)                       */
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/**@file    clsvar_gamssymbol.cpp
 * @ingroup CLASSIFIERS
 * @brief   variables which have the same symbol are put into same class
 * @author  Stefanie Koß
 */
 
/*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
 
#include "clsvar_gamssymbol.h"
#include "cons_decomp.h"
#include "cons_decomp.hpp"
#include <vector>
#include <stdio.h>
#include <sstream>
 
#include "class_detprobdata.h"
 
#include "class_varpartition.h"
#include "scip_misc.h"
 
/* classifier properties */
#define DEC_CLASSIFIERNAME        "gamssymbol"              /**< name of classifier */
#define DEC_DESC                  "symbol in gams file"     /**< short description of classification */
#define DEC_PRIORITY              0                         /**< priority of this classifier */
 
#define DEC_ENABLED               TRUE
 
 
/*
 * Data structures
 */
 
/** classifier handler data */
struct DEC_ClassifierData
{
   std::map<std::string, int>*      vartosymbol;            /**< maps variable name to the corresponding symbol index */
};
 
/*
 * Local methods
 */
 
/* put your local methods here, and declare them static */
 
 
/*
 * classifier callback methods
 */
 
/** destructor of classifier to free user data (called when GCG is exiting) */
static
DEC_DECL_FREEVARCLASSIFIER(classifierFree)
{
   assert(scip != NULL);
 
   DEC_CLASSIFIERDATA* classifierdata = DECvarClassifierGetData(classifier);
   assert(classifierdata != NULL);
   assert(strcmp(DECvarClassifierGetName(classifier), DEC_CLASSIFIERNAME) == 0);
 
   delete classifierdata->vartosymbol;
 
   SCIPfreeMemory(scip, &classifierdata);
 
   return SCIP_OKAY;
}
 
static
DEC_DECL_VARCLASSIFY(classifierClassify)
{
   gcg::DETPROBDATA* detprobdata;
   if( transformed )
   {
      detprobdata = GCGconshdlrDecompGetDetprobdataPresolved(scip);
   }
   else
   {
      detprobdata = GCGconshdlrDecompGetDetprobdataOrig(scip);
   }
 
   int nvar = detprobdata->getNVars();
   std::vector<int> nvarsForClass( 0 );         // [i] holds number of variables for class i
   std::vector<int> symbolidxForClass( 0 );     // [i] holds symbol index for class i
   std::vector<int> classForVar( nvar, - 1 );   // [i] holds class index for variable i -> indexing over detection internal variable array!
   int counterClasses = 0;
 
   DEC_VARCLASSIFIER* classifier = DECfindVarClassifier(scip, DEC_CLASSIFIERNAME);
   assert(classifier != NULL);
 
   DEC_CLASSIFIERDATA* classdata = DECvarClassifierGetData(classifier);
   assert(classdata != NULL);
 
   /* firstly, assign all variables to classindices */
   // iterate over variables in detection and lookup in classdata->vartosymbol
   // iterating over classdata->vartosymbol and lookup variables with getIndexForVar fails with assertion if variable is not found -> should return error value?
   for( int varid = 0; varid < detprobdata->getNVars(); ++ varid )
   {
      SCIP_VAR* var = detprobdata->getVar(varid);
      std::string varname = std::string( SCIPvarGetName( var ) );
      auto symbolidxiter = classdata->vartosymbol->find(varname);
      int symbolidx;
      if( symbolidxiter != classdata->vartosymbol->end() )
      {
         symbolidx = symbolidxiter->second;
      }
      else
      {
         symbolidx = -1;
      }
      
      bool classfound = false;
 
      /* check if class for symbol index exists */
      for( size_t classid = 0; classid < symbolidxForClass.size(); ++classid )
      {
         if( symbolidx == symbolidxForClass[classid] )
         {
            classfound = true;
            classForVar[varid] = classid;
            ++nvarsForClass[classid];
            break;
         }
      }
 
      /* if not, create a new class index */
      if( !classfound )
      {
         classForVar[varid] = counterClasses;
         ++counterClasses;
         symbolidxForClass.push_back( symbolidx );
         nvarsForClass.push_back( 1 );
      }
   }
   assert( counterClasses == (int) symbolidxForClass.size() );
 
   /* secondly, use these information to create a ConsPartition */
   gcg::VarPartition* partition = new gcg::VarPartition(scip, "gamssymbols", counterClasses, detprobdata->getNVars() );
 
   /* set class names and descriptions of every class */
   for( int c = 0; c < partition->getNClasses(); ++ c )
   {
      std::stringstream text;
      text << symbolidxForClass[c];
      partition->setClassName( c, text.str().c_str() );
      text.str( "" );
      text.clear();
      text << "This class contains all variables with gams symbol index" << symbolidxForClass[c] << ".";
      partition->setClassDescription( c, text.str().c_str() );
   }
 
   /* copy the constraint assignment information found in first step */
   for( int i = 0; i < partition->getNVars(); ++ i )
   {
      partition->assignVarToClass( i, classForVar[i] );
   }
   SCIPverbMessage(scip, SCIP_VERBLEVEL_HIGH, NULL, " Varclassifier \"%s\" yields a classification with %d  different variable classes \n", partition->getName(), partition->getNClasses() );
 
   detprobdata->addVarPartition(partition);
   return SCIP_OKAY;
}
 
/*
 * classifier specific interface methods
 */
 
// SHOW
/** adds an entry to clsdata->vartosymbol */
SCIP_RETCODE DECvarClassifierGamssymbolAddEntry(
   DEC_VARCLASSIFIER*   classifier,
   SCIP_VAR*            var,
   int                  symbolIdx
)
{
   assert(classifier != NULL);
   DEC_CLASSIFIERDATA* classdata = DECvarClassifierGetData(classifier);
   assert(classdata != NULL);
 
   std::string varname = SCIPvarGetName( var );
   char varnametrans[SCIP_MAXSTRLEN];
   (void) SCIPsnprintf(varnametrans, SCIP_MAXSTRLEN, "t_%s", varname.c_str());
   std::string nametrans(varnametrans);
   classdata->vartosymbol->insert({varname, symbolIdx});
   classdata->vartosymbol->insert({varnametrans, symbolIdx});
 
   return SCIP_OKAY;
}
 
/** creates the handler for gamssymbol classifier and includes it in SCIP */
SCIP_RETCODE SCIPincludeVarClassifierGamssymbol(
   SCIP*                 scip                /**< SCIP data structure */
)
{
   DEC_CLASSIFIERDATA* classifierdata = NULL;
 
   SCIP_CALL( SCIPallocMemory(scip, &classifierdata) );
   assert(classifierdata != NULL);
   classifierdata->vartosymbol = new std::map<std::string, int>();
 
   SCIP_CALL( DECincludeVarClassifier(scip, DEC_CLASSIFIERNAME, DEC_DESC, DEC_PRIORITY, DEC_ENABLED, classifierdata, classifierFree, classifierClassify) );
 
   return SCIP_OKAY;
}