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/****************************************************************************** |
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* Top contributors (to current version): |
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* Tim King, Morgan Deters |
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* |
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* This file is part of the cvc5 project. |
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* |
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* Copyright (c) 2009-2021 by the authors listed in the file AUTHORS |
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* in the top-level source directory and their institutional affiliations. |
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* All rights reserved. See the file COPYING in the top-level source |
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* directory for licensing information. |
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* **************************************************************************** |
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* |
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* [[ Add one-line brief description here ]] |
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* |
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* [[ Add lengthier description here ]] |
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* \todo document this file |
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*/ |
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#include "cvc5_private.h" |
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#pragma once |
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#include <vector> |
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#include "theory/arith/arithvar.h" |
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#include "theory/arith/matrix.h" |
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#include "util/dense_map.h" |
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#include "util/rational.h" |
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namespace cvc5 { |
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namespace theory { |
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namespace arith { |
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/** |
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* A Tableau is a Rational matrix that keeps its rows in solved form. |
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* Each row has a basic variable with coefficient -1 that is solved. |
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* Tableau is optimized for pivoting. |
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* The tableau should only be updated via pivot calls. |
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*/ |
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19706 |
class Tableau : public Matrix<Rational> { |
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public: |
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private: |
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typedef DenseMap<RowIndex> BasicToRowMap; |
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// Set of all of the basic variables in the tableau. |
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// ArithVarMap<RowIndex> : ArithVar |-> RowIndex |
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BasicToRowMap d_basic2RowIndex; |
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// RowIndex |-> Basic Variable |
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typedef DenseMap<ArithVar> RowIndexToBasicMap; |
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RowIndexToBasicMap d_rowIndex2basic; |
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public: |
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Tableau() : Matrix<Rational>(Rational(0)) {} |
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typedef Matrix<Rational>::ColIterator ColIterator; |
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typedef Matrix<Rational>::RowIterator RowIterator; |
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typedef BasicToRowMap::const_iterator BasicIterator; |
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typedef MatrixEntry<Rational> Entry; |
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bool isBasic(ArithVar v) const{ |
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return d_basic2RowIndex.isKey(v); |
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} |
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void debugPrintIsBasic(ArithVar v) const { |
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if(isBasic(v)){ |
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Warning() << v << " is basic." << std::endl; |
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}else{ |
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Warning() << v << " is non-basic." << std::endl; |
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} |
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} |
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BasicIterator beginBasic() const { |
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return d_basic2RowIndex.begin(); |
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} |
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BasicIterator endBasic() const { |
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return d_basic2RowIndex.end(); |
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} |
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RowIndex basicToRowIndex(ArithVar x) const { |
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return d_basic2RowIndex[x]; |
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} |
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ArithVar rowIndexToBasic(RowIndex rid) const { |
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Assert(d_rowIndex2basic.isKey(rid)); |
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return d_rowIndex2basic[rid]; |
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} |
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ColIterator colIterator(ArithVar x) const { |
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return getColumn(x).begin(); |
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} |
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RowIterator ridRowIterator(RowIndex rid) const { |
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return getRow(rid).begin(); |
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} |
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RowIterator basicRowIterator(ArithVar basic) const { |
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return ridRowIterator(basicToRowIndex(basic)); |
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} |
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const Entry& basicFindEntry(ArithVar basic, ArithVar col) const { |
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return findEntry(basicToRowIndex(basic), col); |
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} |
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/** |
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* Adds a row to the tableau. |
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* The new row is equivalent to: |
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* basicVar = \f$\sum_i\f$ coeffs[i] * variables[i] |
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* preconditions: |
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* basicVar is already declared to be basic |
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* basicVar does not have a row associated with it in the tableau. |
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* |
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* Note: each variables[i] does not have to be non-basic. |
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* Pivoting will be mimicked if it is basic. |
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*/ |
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void addRow(ArithVar basicVar, |
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const std::vector<Rational>& coeffs, |
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const std::vector<ArithVar>& variables); |
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/** |
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* preconditions: |
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* x_r is basic, |
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* x_s is non-basic, and |
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* a_rs != 0. |
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*/ |
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void pivot(ArithVar basicOld, ArithVar basicNew, CoefficientChangeCallback& cb); |
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void removeBasicRow(ArithVar basic); |
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uint32_t basicRowLength(ArithVar basic) const{ |
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RowIndex ridx = basicToRowIndex(basic); |
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return getRowLength(ridx); |
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} |
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/** |
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* to += mult * from |
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* replacing from with its row. |
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*/ |
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void substitutePlusTimesConstant(ArithVar to, ArithVar from, const Rational& mult, CoefficientChangeCallback& cb); |
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void directlyAddToCoefficient(ArithVar rowVar, ArithVar col, const Rational& mult, CoefficientChangeCallback& cb){ |
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RowIndex ridx = basicToRowIndex(rowVar); |
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manipulateRowEntry(ridx, col, mult, cb); |
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} |
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/* Returns the complexity of a row in the tableau. */ |
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uint32_t rowComplexity(ArithVar basic) const; |
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/* Returns the average complexity of the rows in the tableau. */ |
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double avgRowComplexity() const; |
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void printBasicRow(ArithVar basic, std::ostream& out); |
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private: |
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/* Changes the basic variable on the row for basicOld to basicNew. */ |
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void rowPivot(ArithVar basicOld, ArithVar basicNew, CoefficientChangeCallback& cb); |
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};/* class Tableau */ |
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} // namespace arith |
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} // namespace theory |
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} // namespace cvc5 |