src/theory/arith/tableau.cpp

   1 /*********************                                                        */
   2 /*! \file tableau.cpp
   3  ** \verbatim
   4  ** Original author: taking
   5  ** Major contributors: none
   6  ** Minor contributors (to current version): none
   7  ** This file is part of the CVC4 prototype.
   8  ** Copyright (c) 2009, 2010  The Analysis of Computer Systems Group (ACSys)
   9  ** Courant Institute of Mathematical Sciences
  10  ** New York University
  11  ** See the file COPYING in the top-level source directory for licensing
  12  ** information.\endverbatim
  13  **
  14  ** \brief [[ Add one-line brief description here ]]
  15  **
  16  ** [[ Add lengthier description here ]]
  17  ** \todo document this file
  18  **/
  19
  20
  21 #include "theory/arith/tableau.h"
  22
  23 using namespace CVC4;
  24 using namespace CVC4::theory;
  25 using namespace CVC4::theory::arith;
  26
  27 void Tableau::addRow(ArithVar basicVar,
  28                      const std::vector<Rational>& coeffs,
  29                      const std::vector<ArithVar>& variables){
  30
  31   Assert(coeffs.size() == variables.size());
  32   Assert(d_basicManager.isMember(basicVar));
  33
  34   //The new basic variable cannot already be a basic variable
  35   Assert(!d_activeBasicVars.isMember(basicVar));
  36   d_activeBasicVars.add(basicVar);
  37   ReducedRowVector* row_current = new ReducedRowVector(basicVar,variables, coeffs,d_rowCount);
  38   d_rowsTable[basicVar] = row_current;
  39
  40   //A variable in the row may have been made non-basic already.
  41   //If this is the case we fake pivoting this variable
  42   vector<ArithVar>::const_iterator varsIter = variables.begin();
  43   vector<ArithVar>::const_iterator varsEnd = variables.end();
  44
  45   for( ; varsIter != varsEnd; ++varsIter){
  46     ArithVar var = *varsIter;
  47
  48     if(d_basicManager.isMember(var)){
  49       /*
  50       if(!isActiveBasicVariable(var)){
  51         reinjectBasic(var);
  52       }
  53       Assert(isActiveBasicVariable(var));
  54       */
  55       Assert(d_activeBasicVars.isMember(var));
  56
  57       ReducedRowVector& row_var = lookup(var);
  58       row_current->substitute(row_var);
  59     }
  60   }
  61 }
  62
  63 ReducedRowVector* Tableau::removeRow(ArithVar basic){
  64   Assert(d_basicManager.isMember(basic));
  65   Assert(d_activeBasicVars.isMember(basic));
  66
  67   ReducedRowVector* row = d_rowsTable[basic];
  68
  69   d_activeBasicVars.remove(basic);
  70   d_rowsTable[basic] = NULL;
  71
  72   return row;
  73 }
  74
  75 void Tableau::pivot(ArithVar x_r, ArithVar x_s){
  76   Assert(d_basicManager.isMember(x_r));
  77   Assert(!d_basicManager.isMember(x_s));
  78
  79   Debug("tableau") << "Tableau::pivot(" <<  x_r <<", " <<x_s <<")"  << endl;
  80
  81   ReducedRowVector* row_s = d_rowsTable[x_r];
  82   Assert(row_s != NULL);
  83   Assert(row_s->has(x_s));
  84
  85   //Swap x_r and x_s in d_activeRows
  86   d_rowsTable[x_s] = row_s;
  87   d_rowsTable[x_r] = NULL;
  88
  89   d_activeBasicVars.remove(x_r);
  90   d_basicManager.remove(x_r);
  91
  92   d_activeBasicVars.add(x_s);
  93   d_basicManager.add(x_s);
  94
  95   row_s->pivot(x_s);
  96
  97   for(ArithVarSet::iterator basicIter = begin(), endIter = end();
  98       basicIter != endIter; ++basicIter){
  99     ArithVar basic = *basicIter;
 100     if(basic == x_s) continue;
 101
 102     ReducedRowVector& row_k = lookup(basic);
 103     if(row_k.has(x_s)){
 104       d_activityMonitor[basic] += 30;
 105       row_k.substitute(*row_s);
 106     }
 107   }
 108 }
 109 void Tableau::printTableau(){
 110   Debug("tableau") << "Tableau::d_activeRows"  << endl;
 111
 112   typedef RowsTable::iterator table_iter;
 113   for(table_iter rowIter = d_rowsTable.begin(), end = d_rowsTable.end();
 114       rowIter != end; ++rowIter){
 115     ReducedRowVector* row_k = *rowIter;
 116     if(row_k != NULL){
 117       row_k->printRow();
 118     }
 119   }
 120 }
 121
 122
 123 /*
 124 void Tableau::updateRow(ReducedRowVector* row){
 125   ArithVar basic = row->basic();
 126   for(ReducedRowVector::NonZeroIterator i=row->beginNonZero(), endIter = row->endNonZero(); i != endIter; ){
 127     ArithVar var = i->first;
 128     ++i;
 129     if(var != basic && d_basicManager.isMember(var)){
 130       ReducedRowVector* row_var = isActiveBasicVariable(var) ? lookup(var) : lookupEjected(var);
 131
 132       Assert(row_var != row);
 133       row->substitute(*row_var);
 134
 135       i = row->beginNonZero();
 136       endIter = row->endNonZero();
 137     }
 138   }
 139 }
 140 */