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/********************* */
/*! \file tableau.cpp
** \verbatim
** Top contributors (to current version):
** Tim King
** This file is part of the CVC4 project.
** Copyright (c) 2009-2020 by the authors listed in the file AUTHORS
** in the top-level source directory) and their institutional affiliations.
** All rights reserved. See the file COPYING in the top-level source
** directory for licensing information.\endverbatim
**
** \brief [[ Add one-line brief description here ]]
**
** [[ Add lengthier description here ]]
** \todo document this file
**/
#include "base/output.h"
#include "theory/arith/tableau.h"
using namespace std;
namespace CVC4 {
namespace theory {
namespace arith {
void Tableau::pivot(ArithVar oldBasic, ArithVar newBasic, CoefficientChangeCallback& cb){
Assert(isBasic(oldBasic));
Assert(!isBasic(newBasic));
Assert(d_mergeBuffer.empty());
Debug("tableau") << "Tableau::pivot(" << oldBasic <<", " << newBasic <<")" << endl;
RowIndex ridx = basicToRowIndex(oldBasic);
rowPivot(oldBasic, newBasic, cb);
Assert(ridx == basicToRowIndex(newBasic));
loadRowIntoBuffer(ridx);
ColIterator colIter = colIterator(newBasic);
while(!colIter.atEnd()){
EntryID id = colIter.getID();
Entry& entry = d_entries.get(id);
++colIter; //needs to be incremented before the variable is removed
if(entry.getRowIndex() == ridx){ continue; }
RowIndex to = entry.getRowIndex();
Rational coeff = entry.getCoefficient();
if(cb.canUseRow(to)){
rowPlusBufferTimesConstant(to, coeff, cb);
}else{
rowPlusBufferTimesConstant(to, coeff);
}
}
clearBuffer();
//Clear the column for used for this variable
Assert(d_mergeBuffer.empty());
Assert(!isBasic(oldBasic));
Assert(isBasic(newBasic));
Assert(getColLength(newBasic) == 1);
}
/**
* Changes basic to newbasic (a variable on the row).
*/
void Tableau::rowPivot(ArithVar basicOld, ArithVar basicNew, CoefficientChangeCallback& cb){
Assert(isBasic(basicOld));
Assert(!isBasic(basicNew));
RowIndex rid = basicToRowIndex(basicOld);
EntryID newBasicID = findOnRow(rid, basicNew);
Assert(newBasicID != ENTRYID_SENTINEL);
Tableau::Entry& newBasicEntry = d_entries.get(newBasicID);
const Rational& a_rs = newBasicEntry.getCoefficient();
int a_rs_sgn = a_rs.sgn();
Rational negInverseA_rs = -(a_rs.inverse());
for(RowIterator i = basicRowIterator(basicOld); !i.atEnd(); ++i){
EntryID id = i.getID();
Tableau::Entry& entry = d_entries.get(id);
entry.getCoefficient() *= negInverseA_rs;
}
d_basic2RowIndex.remove(basicOld);
d_basic2RowIndex.set(basicNew, rid);
d_rowIndex2basic.set(rid, basicNew);
cb.multiplyRow(rid, -a_rs_sgn);
}
void Tableau::addRow(ArithVar basic,
const std::vector<Rational>& coefficients,
const std::vector<ArithVar>& variables)
{
Assert(basic < getNumColumns());
Assert(debugIsASet(variables));
Assert(coefficients.size() == variables.size());
Assert(!isBasic(basic));
RowIndex newRow = Matrix<Rational>::addRow(coefficients, variables);
addEntry(newRow, basic, Rational(-1));
Assert(!d_basic2RowIndex.isKey(basic));
Assert(!d_rowIndex2basic.isKey(newRow));
d_basic2RowIndex.set(basic, newRow);
d_rowIndex2basic.set(newRow, basic);
if(Debug.isOn("matrix")){ printMatrix(); }
NoEffectCCCB noeffect;
NoEffectCCCB* nep = &noeffect;
CoefficientChangeCallback* cccb = static_cast<CoefficientChangeCallback*>(nep);
vector<Rational>::const_iterator coeffIter = coefficients.begin();
vector<ArithVar>::const_iterator varsIter = variables.begin();
vector<ArithVar>::const_iterator varsEnd = variables.end();
for(; varsIter != varsEnd; ++coeffIter, ++varsIter){
ArithVar var = *varsIter;
if(isBasic(var)){
Rational coeff = *coeffIter;
RowIndex ri = basicToRowIndex(var);
loadRowIntoBuffer(ri);
rowPlusBufferTimesConstant(newRow, coeff, *cccb);
clearBuffer();
}
}
if(Debug.isOn("matrix")) { printMatrix(); }
Assert(debugNoZeroCoefficients(newRow));
Assert(debugMatchingCountsForRow(newRow));
Assert(getColLength(basic) == 1);
}
void Tableau::removeBasicRow(ArithVar basic){
RowIndex rid = basicToRowIndex(basic);
removeRow(rid);
d_basic2RowIndex.remove(basic);
d_rowIndex2basic.remove(rid);
}
void Tableau::substitutePlusTimesConstant(ArithVar to, ArithVar from, const Rational& mult, CoefficientChangeCallback& cb){
if(!mult.isZero()){
RowIndex to_idx = basicToRowIndex(to);
addEntry(to_idx, from, mult); // Add an entry to be cancelled out
RowIndex from_idx = basicToRowIndex(from);
cb.update(to_idx, from, 0, mult.sgn());
loadRowIntoBuffer(from_idx);
rowPlusBufferTimesConstant(to_idx, mult, cb);
clearBuffer();
}
}
uint32_t Tableau::rowComplexity(ArithVar basic) const{
uint32_t complexity = 0;
for(RowIterator i = basicRowIterator(basic); !i.atEnd(); ++i){
const Entry& e = *i;
complexity += e.getCoefficient().complexity();
}
return complexity;
}
double Tableau::avgRowComplexity() const{
double sum = 0;
uint32_t rows = 0;
for(BasicIterator i = beginBasic(), i_end = endBasic(); i != i_end; ++i){
sum += rowComplexity(*i);
rows++;
}
return (rows == 0) ? 0 : (sum/rows);
}
void Tableau::printBasicRow(ArithVar basic, std::ostream& out){
printRow(basicToRowIndex(basic), out);
}
}/* CVC4::theory::arith namespace */
}/* CVC4::theory namespace */
}/* CVC4 namespace */
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