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/********************* */
/*! \file bounded_integers.h
** \verbatim
** Top contributors (to current version):
** Andrew Reynolds, Mathias Preiner
** This file is part of the CVC4 project.
** Copyright (c) 2009-2018 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
**
** [[ Add lengthier description here ]]
** \todo document this file
**/
#include "cvc4_private.h"
#ifndef __CVC4__BOUNDED_INTEGERS_H
#define __CVC4__BOUNDED_INTEGERS_H
#include "theory/quantifiers_engine.h"
#include "context/context.h"
#include "context/context_mm.h"
namespace CVC4 {
namespace theory {
class RepSetIterator;
namespace quantifiers {
class BoundedIntegers : public QuantifiersModule
{
typedef context::CDHashMap<Node, bool, NodeHashFunction> NodeBoolMap;
typedef context::CDHashMap<Node, int, NodeHashFunction> NodeIntMap;
typedef context::CDHashMap<Node, Node, NodeHashFunction> NodeNodeMap;
typedef context::CDHashMap<int, bool> IntBoolMap;
public:
enum {
BOUND_FINITE,
BOUND_INT_RANGE,
BOUND_SET_MEMBER,
BOUND_FIXED_SET,
BOUND_NONE
};
private:
//for determining bounds
bool isBound( Node f, Node v );
bool hasNonBoundVar( Node f, Node b, std::map< Node, bool >& visited );
bool hasNonBoundVar( Node f, Node b );
//bound type
std::map< Node, std::map< Node, unsigned > > d_bound_type;
std::map< Node, std::vector< Node > > d_set;
std::map< Node, std::map< Node, int > > d_set_nums;
std::map< Node, std::map< Node, Node > > d_range;
std::map< Node, std::map< Node, Node > > d_nground_range;
//integer lower/upper bounds
std::map< Node, std::map< Node, Node > > d_bounds[2];
//set membership range
std::map< Node, std::map< Node, Node > > d_setm_range;
std::map< Node, std::map< Node, Node > > d_setm_range_lit;
/** set membership element choice functions
*
* For each set S and integer n, d_setm_choice[S][n] is the canonical
* representation for the (n+1)^th member of set S. It is of the form:
* choice x. (|S| <= n OR ( x in S AND
* distinct( x, d_setm_choice[S][0], ..., d_setm_choice[S][n-1] ) ) )
*/
std::map<Node, std::vector<Node> > d_setm_choice;
//fixed finite set range
std::map< Node, std::map< Node, std::vector< Node > > > d_fixed_set_gr_range;
std::map< Node, std::map< Node, std::vector< Node > > > d_fixed_set_ngr_range;
void process( Node q, Node n, bool pol,
std::map< Node, unsigned >& bound_lit_type_map,
std::map< int, std::map< Node, Node > >& bound_lit_map,
std::map< int, std::map< Node, bool > >& bound_lit_pol_map,
std::map< int, std::map< Node, Node > >& bound_int_range_term,
std::map< Node, std::vector< Node > >& bound_fixed_set );
bool processEqDisjunct( Node q, Node n, Node& v, std::vector< Node >& v_cases );
void processMatchBoundVars( Node q, Node n, std::vector< Node >& bvs, std::map< Node, bool >& visited );
std::vector< Node > d_bound_quants;
private:
/**
* This decision strategy is used for minimizing the value of an integer
* arithmetic term t. It decides positively on literals of the form
* t < 0, t <= 0, t <= 1, t <=2, and so on.
*/
class IntRangeDecisionHeuristic : public DecisionStrategyFmf
{
public:
IntRangeDecisionHeuristic(Node r,
context::Context* c,
context::Context* u,
Valuation valuation,
bool isProxy);
/** make the n^th literal of this strategy */
Node mkLiteral(unsigned n) override;
/** identify */
std::string identify() const override
{
return std::string("bound_int_range");
}
/** Returns the current proxy lemma if one exists (see below). */
Node proxyCurrentRangeLemma();
private:
/** The range we are minimizing */
Node d_range;
/** a proxy of the range
*
* When option::fmfBoundLazy is enabled, this class uses a lazy strategy
* for enforcing the bounds on term t by using a fresh variable x of type
* integer. The point of this variable is to serve as a proxy for t, so
* that we can decide on literals of the form x <= c instead of t <= c. The
* advantage of this is that we avoid unfairness, say, if t is constrained
* to be strictly greater c. Then, at full effort check, we add "proxy
* lemmas" of the form: (t <= c) <=> (x <= c) for the current minimal
* upper bound c for x.
*/
Node d_proxy_range;
/** ranges that have been proxied
*
* This is a user-context-dependent cache that stores which value we have
* added proxy lemmas for.
*/
IntBoolMap d_ranges_proxied;
};
private:
//information for minimizing ranges
std::vector< Node > d_ranges;
/** Decision heuristics for each integer range */
std::map<Node, std::unique_ptr<IntRangeDecisionHeuristic>> d_rms;
private:
//class to store whether bounding lemmas have been added
class BoundInstTrie
{
public:
std::map< Node, BoundInstTrie > d_children;
bool hasInstantiated( std::vector< Node > & vals, int index = 0, bool madeNew = false ){
if( index>=(int)vals.size() ){
return !madeNew;
}else{
Node n = vals[index];
if( d_children.find(n)==d_children.end() ){
madeNew = true;
}
return d_children[n].hasInstantiated(vals,index+1,madeNew);
}
}
};
std::map< Node, std::map< Node, BoundInstTrie > > d_bnd_it;
private:
void setBoundedVar( Node f, Node v, unsigned bound_type );
public:
BoundedIntegers( context::Context* c, QuantifiersEngine* qe );
virtual ~BoundedIntegers();
void presolve() override;
bool needsCheck(Theory::Effort e) override;
void check(Theory::Effort e, QEffort quant_e) override;
void checkOwnership(Node q) override;
bool isBoundVar( Node q, Node v ) { return std::find( d_set[q].begin(), d_set[q].end(), v )!=d_set[q].end(); }
unsigned getBoundVarType( Node q, Node v );
unsigned getNumBoundVars( Node q ) { return d_set[q].size(); }
Node getBoundVar( Node q, int i ) { return d_set[q][i]; }
private:
//for integer range
Node getLowerBound( Node q, Node v ){ return d_bounds[0][q][v]; }
Node getUpperBound( Node q, Node v ){ return d_bounds[1][q][v]; }
void getBounds( Node f, Node v, RepSetIterator * rsi, Node & l, Node & u );
void getBoundValues( Node f, Node v, RepSetIterator * rsi, Node & l, Node & u );
bool isGroundRange(Node f, Node v);
//for set range
Node getSetRange( Node q, Node v, RepSetIterator * rsi );
Node getSetRangeValue( Node q, Node v, RepSetIterator * rsi );
Node matchBoundVar( Node v, Node t, Node e );
bool getRsiSubsitution( Node q, Node v, std::vector< Node >& vars, std::vector< Node >& subs, RepSetIterator * rsi );
public:
bool getBoundElements( RepSetIterator * rsi, bool initial, Node q, Node v, std::vector< Node >& elements );
/** Identify this module */
std::string identify() const override { return "BoundedIntegers"; }
};
}
}
}
#endif
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