constraint.hpp

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#ifndef LIBSNARK_GADGETLIB2_INCLUDE_GADGETLIB2_CONSTRAINT_HPP_
#define LIBSNARK_GADGETLIB2_INCLUDE_GADGETLIB2_CONSTRAINT_HPP_
 
#include <libsnark/gadgetlib2/variable.hpp>
#include <string>
#include <vector>
 
namespace gadgetlib2
{
 
enum class PrintOptions {
    DBG_PRINT_IF_NOT_SATISFIED,
    DBG_PRINT_IF_TRUE,
    DBG_PRINT_IF_FALSE,
    NO_DBG_PRINT
};
 
/*************************************************************************************************/
/*************************************************************************************************/
/******************* ******************/
/*******************                    class Constraint ******************/
/******************* ******************/
/*************************************************************************************************/
/*************************************************************************************************/
 
class Constraint
{
public:
    explicit Constraint(
        const ::std::string &name); // casting disallowed by 'explicit'
    ::std::string name() const; 
 
    virtual bool isSatisfied(
        const VariableAssignment &assignment,
        const PrintOptions &printOnFail) const = 0;
    virtual ::std::string annotation() const = 0;
    virtual const Variable::set getUsedVariables() const = 0;
    virtual Polynomial asPolynomial() const = 0;
 
protected:
#ifdef DEBUG
    ::std::string name_;
#endif
 
}; // class Constraint
 
/***********************************/
/***   END OF CLASS DEFINITION   ***/
/***********************************/
 
/*************************************************************************************************/
/*************************************************************************************************/
/******************* ******************/
/*******************                 class Rank1Constraint ******************/
/******************* ******************/
/*************************************************************************************************/
/*************************************************************************************************/
class Rank1Constraint : public Constraint
{
private:
    LinearCombination a_, b_, c_; // <a,x> * <b,x> = <c,x>
public:
    Rank1Constraint(
        const LinearCombination &a,
        const LinearCombination &b,
        const LinearCombination &c,
        const ::std::string &name);
 
    LinearCombination a() const;
    LinearCombination b() const;
    LinearCombination c() const;
 
    virtual bool isSatisfied(
        const VariableAssignment &assignment,
        const PrintOptions &printOnFail = PrintOptions::NO_DBG_PRINT) const;
    virtual ::std::string annotation() const;
    virtual const Variable::set getUsedVariables()
        const; 
    virtual Polynomial asPolynomial() const { return a_ * b_ - c_; }
}; // class Rank1Constraint
 
/***********************************/
/***   END OF CLASS DEFINITION   ***/
/***********************************/
 
/*************************************************************************************************/
/*************************************************************************************************/
/******************* ******************/
/*******************                 class PolynomialConstraint
 * ******************/
/******************* ******************/
/*************************************************************************************************/
/*************************************************************************************************/
 
class PolynomialConstraint : public Constraint
{
private:
    Polynomial a_, b_;
 
public:
    PolynomialConstraint(
        const Polynomial &a, const Polynomial &b, const ::std::string &name);
 
    bool isSatisfied(
        const VariableAssignment &assignment,
        const PrintOptions &printOnFail = PrintOptions::NO_DBG_PRINT) const;
    ::std::string annotation() const;
    virtual const Variable::set getUsedVariables()
        const; 
    virtual Polynomial asPolynomial() const { return a_ - b_; }
}; // class PolynomialConstraint
 
/***********************************/
/***   END OF CLASS DEFINITION   ***/
/***********************************/
 
/*************************************************************************************************/
/*************************************************************************************************/
/******************* ******************/
/*******************                   class ConstraintSystem
 * ******************/
/******************* ******************/
/*************************************************************************************************/
/*************************************************************************************************/
 
class ConstraintSystem
{
protected:
    typedef ::std::shared_ptr<Constraint> ConstraintPtr;
    ::std::vector<ConstraintPtr> constraintsPtrs_;
 
public:
    ConstraintSystem() : constraintsPtrs_(){};
 
    bool isSatisfied(
        const VariableAssignment &assignment,
        const PrintOptions &printOnFail = PrintOptions::NO_DBG_PRINT) const;
    void addConstraint(const Rank1Constraint &c);
    void addConstraint(const PolynomialConstraint &c);
    ::std::string annotation() const;
    Variable::set getUsedVariables() const;
 
    typedef ::std::set<::std::unique_ptr<Polynomial>> PolyPtrSet;
    PolyPtrSet getConstraintPolynomials() const
    {
        PolyPtrSet retset;
        for (const auto &pConstraint : constraintsPtrs_) {
            retset.insert(::std::unique_ptr<Polynomial>(
                new Polynomial(pConstraint->asPolynomial())));
        }
        return retset;
    }
    size_t getNumberOfConstraints() { return constraintsPtrs_.size(); }
    ConstraintPtr getConstraint(size_t idx) { return constraintsPtrs_[idx]; }
    friend class GadgetLibAdapter;
}; // class ConstraintSystem
 
/***********************************/
/***   END OF CLASS DEFINITION   ***/
/***********************************/
 
} // namespace gadgetlib2
 
#endif // LIBSNARK_GADGETLIB2_INCLUDE_GADGETLIB2_CONSTRAINT_HPP_