r1cs.hpp

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#ifndef R1CS_HPP_
#define R1CS_HPP_
 
#include <cstdlib>
#include <iostream>
#include <libsnark/relations/variable.hpp>
#include <map>
#include <string>
#include <vector>
 
namespace libsnark
{
 
/************************* R1CS constraint ***********************************/
 
template<typename FieldT> class r1cs_constraint;
 
template<typename FieldT>
std::ostream &operator<<(std::ostream &out, const r1cs_constraint<FieldT> &c);
 
template<typename FieldT>
std::istream &operator>>(std::istream &in, r1cs_constraint<FieldT> &c);
 
template<typename FieldT> class r1cs_constraint
{
public:
    linear_combination<FieldT> a, b, c;
 
    r1cs_constraint(){};
    r1cs_constraint(
        const linear_combination<FieldT> &a,
        const linear_combination<FieldT> &b,
        const linear_combination<FieldT> &c);
 
    r1cs_constraint(
        const std::initializer_list<linear_combination<FieldT>> &A,
        const std::initializer_list<linear_combination<FieldT>> &B,
        const std::initializer_list<linear_combination<FieldT>> &C);
 
    bool operator==(const r1cs_constraint<FieldT> &other) const;
 
    friend std::ostream &operator<<<FieldT>(
        std::ostream &out, const r1cs_constraint<FieldT> &c);
    friend std::istream &operator>>
        <FieldT>(std::istream &in, r1cs_constraint<FieldT> &c);
};
 
/************************* R1CS variable assignment **************************/
 
/* TODO: specify that it does *NOT* include the constant 1 */
template<typename FieldT> using r1cs_primary_input = std::vector<FieldT>;
 
template<typename FieldT> using r1cs_auxiliary_input = std::vector<FieldT>;
 
template<typename FieldT>
using r1cs_variable_assignment =
    std::vector<FieldT>; /* note the changed name! (TODO: remove this comment
                            after primary_input transition is complete) */
 
/************************* R1CS constraint system ****************************/
 
template<typename FieldT> class r1cs_constraint_system;
 
template<typename FieldT>
std::ostream &operator<<(
    std::ostream &out, const r1cs_constraint_system<FieldT> &cs);
 
template<typename FieldT>
std::istream &operator>>(std::istream &in, r1cs_constraint_system<FieldT> &cs);
 
template<typename FieldT> class r1cs_constraint_system
{
public:
    size_t primary_input_size;
    size_t auxiliary_input_size;
 
    std::vector<r1cs_constraint<FieldT>> constraints;
 
    r1cs_constraint_system() : primary_input_size(0), auxiliary_input_size(0) {}
 
    size_t num_inputs() const;
    size_t num_variables() const;
    size_t num_constraints() const;
 
#ifdef DEBUG
    std::map<size_t, std::string> constraint_annotations;
    std::map<size_t, std::string> variable_annotations;
#endif
 
    bool is_valid() const;
    bool is_satisfied(
        const r1cs_primary_input<FieldT> &primary_input,
        const r1cs_auxiliary_input<FieldT> &auxiliary_input) const;
 
    void add_constraint(const r1cs_constraint<FieldT> &c);
    void add_constraint(
        const r1cs_constraint<FieldT> &c, const std::string &annotation);
 
    void swap_AB_if_beneficial();
 
    bool operator==(const r1cs_constraint_system<FieldT> &other) const;
 
    friend std::ostream &operator<<<FieldT>(
        std::ostream &out, const r1cs_constraint_system<FieldT> &cs);
    friend std::istream &operator>>
        <FieldT>(std::istream &in, r1cs_constraint_system<FieldT> &cs);
 
    void report_linear_constraint_statistics() const;
};
 
} // namespace libsnark
 
#include <libsnark/relations/constraint_satisfaction_problems/r1cs/r1cs.tcc>
 
#endif // R1CS_HPP_