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/********************* */
/*! \file partial_model.h
** \verbatim
** Original author: Tim King <taking@cs.nyu.edu>
** Major contributors: Morgan Deters <mdeters@cs.nyu.edu>
** Minor contributors (to current version): none
** This file is part of the CVC4 project.
** Copyright (c) 2009-2013 New York University and The University of Iowa
** 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 "cvc4_private.h"
#include "expr/node.h"
#include "context/context.h"
#include "context/cdvector.h"
#include "context/cdo.h"
#include "theory/arith/arithvar.h"
#include "theory/arith/delta_rational.h"
#include "theory/arith/constraint_forward.h"
#include <vector>
#ifndef __CVC4__THEORY__ARITH__PARTIAL_MODEL_H
#define __CVC4__THEORY__ARITH__PARTIAL_MODEL_H
namespace CVC4 {
namespace theory {
namespace arith {
class ArithPartialModel {
private:
unsigned d_mapSize;
//Maps from ArithVar -> T
std::vector<bool> d_hasSafeAssignment;
std::vector<DeltaRational> d_assignment;
std::vector<DeltaRational> d_safeAssignment;
context::CDVector<Constraint> d_ubc;
context::CDVector<Constraint> d_lbc;
// This is true when setDelta() is called, until invalidateDelta is called
bool d_deltaIsSafe;
// Cache of a value of delta to ensure a total order.
Rational d_delta;
// Function to call if the value of delta needs to be recomputed.
RationalCallBack& d_deltaComputingFunc;
/**
* List contains all of the variables that have an unsafe assignment.
*/
typedef std::vector<ArithVar> HistoryList;
HistoryList d_history;
public:
ArithPartialModel(context::Context* c, RationalCallBack& deltaComputation);
/**
* This sets the lower bound for a variable in the current context.
* This must be stronger the previous constraint.
*/
void setLowerBoundConstraint(Constraint lb);
/**
* This sets the upper bound for a variable in the current context.
* This must be stronger the previous constraint.
*/
void setUpperBoundConstraint(Constraint ub);
/** Returns the constraint for the upper bound of a variable. */
inline Constraint getUpperBoundConstraint(ArithVar x) const{
return d_ubc[x];
}
/** Returns the constraint for the lower bound of a variable. */
inline Constraint getLowerBoundConstraint(ArithVar x) const{
return d_lbc[x];
}
/**
* This forces the lower bound for a variable to be relaxed in the current context.
* This is done by forcing the lower bound to be NullConstraint.
* This is an expert only operation! (See primal simplex for an example.)
*/
void forceRelaxLowerBound(ArithVar x);
/**
* This forces the upper bound for a variable to be relaxed in the current context.
* This is done by forcing the upper bound to be NullConstraint.
* This is an expert only operation! (See primal simplex for an example.)
*/
void forceRelaxUpperBound(ArithVar x);
/* Initializes a variable to a safe value.*/
void initialize(ArithVar x, const DeltaRational& r);
/* Gets the last assignment to a variable that is known to be consistent. */
const DeltaRational& getSafeAssignment(ArithVar x) const;
const DeltaRational& getAssignment(ArithVar x, bool safe) const;
/* Reverts all variable assignments to their safe values. */
void revertAssignmentChanges();
/* Commits all variables assignments as safe.*/
void commitAssignmentChanges();
inline bool lowerBoundIsZero(ArithVar x){
return hasLowerBound(x) && getLowerBound(x).sgn() == 0;
}
inline bool upperBoundIsZero(ArithVar x){
return hasUpperBound(x) && getUpperBound(x).sgn() == 0;
}
bool boundsAreEqual(ArithVar x) const;
/* Sets an unsafe variable assignment */
void setAssignment(ArithVar x, const DeltaRational& r);
void setAssignment(ArithVar x, const DeltaRational& safe, const DeltaRational& r);
/** Must know that the bound exists before calling this! */
const DeltaRational& getUpperBound(ArithVar x) const;
const DeltaRational& getLowerBound(ArithVar x) const;
const DeltaRational& getAssignment(ArithVar x) const;
bool equalsLowerBound(ArithVar x, const DeltaRational& c);
bool equalsUpperBound(ArithVar x, const DeltaRational& c);
/**
* If lowerbound > - \infty:
* return getAssignment(x).cmp(getLowerBound(x))
* If lowerbound = - \infty:
* return 1
*/
int cmpToLowerBound(ArithVar x, const DeltaRational& c) const;
inline bool strictlyLessThanLowerBound(ArithVar x, const DeltaRational& c) const{
return cmpToLowerBound(x, c) < 0;
}
inline bool lessThanLowerBound(ArithVar x, const DeltaRational& c) const{
return cmpToLowerBound(x, c) <= 0;
}
inline bool strictlyGreaterThanLowerBound(ArithVar x, const DeltaRational& c) const{
return cmpToLowerBound(x, c) > 0;
}
inline bool greaterThanLowerBound(ArithVar x, const DeltaRational& c) const{
return cmpToLowerBound(x, c) >= 0;
}
/**
* If upperbound < \infty:
* return getAssignment(x).cmp(getUpperBound(x))
* If upperbound = \infty:
* return -1
*/
int cmpToUpperBound(ArithVar x, const DeltaRational& c) const;
inline bool strictlyLessThanUpperBound(ArithVar x, const DeltaRational& c) const{
return cmpToUpperBound(x, c) < 0;
}
inline bool lessThanUpperBound(ArithVar x, const DeltaRational& c) const{
return cmpToUpperBound(x, c) <= 0;
}
inline bool strictlyGreaterThanUpperBound(ArithVar x, const DeltaRational& c) const{
return cmpToUpperBound(x, c) > 0;
}
inline bool greaterThanUpperBound(ArithVar x, const DeltaRational& c) const{
return cmpToUpperBound(x, c) >= 0;
}
bool strictlyBelowUpperBound(ArithVar x) const;
bool strictlyAboveLowerBound(ArithVar x) const;
bool assignmentIsConsistent(ArithVar x) const;
void printModel(ArithVar x);
/** returns true iff x has both a lower and upper bound. */
bool hasEitherBound(ArithVar x) const;
inline bool hasLowerBound(ArithVar x) const{
return d_lbc[x] != NullConstraint;
}
inline bool hasUpperBound(ArithVar x) const{
return d_ubc[x] != NullConstraint;
}
const Rational& getDelta();
inline void invalidateDelta() {
d_deltaIsSafe = false;
}
void setDelta(const Rational& d){
d_delta = d;
d_deltaIsSafe = true;
}
private:
/**
* This function implements the mostly identical:
* revertAssignmentChanges() and commitAssignmentChanges().
*/
void clearSafeAssignments(bool revert);
bool equalSizes();
bool inMaps(ArithVar x) const{
return x < d_mapSize;
}
};/* class ArithPartialModel */
}/* CVC4::theory::arith namespace */
}/* CVC4::theory namespace */
}/* CVC4 namespace */
#endif /* __CVC4__THEORY__ARITH__PARTIAL_MODEL_H */
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