integration.cpp

Go to the documentation of this file.

 
#include <libsnark/gadgetlib2/adapters.hpp>
#include <libsnark/gadgetlib2/integration.hpp>
 
namespace libsnark
{
 
linear_combination<libff::Fr<libff::default_ec_pp>>
convert_gadgetlib2_linear_combination(
    const gadgetlib2::GadgetLibAdapter::linear_combination_t &lc)
{
    typedef libff::Fr<libff::default_ec_pp> FieldT;
    typedef gadgetlib2::GadgetLibAdapter GLA;
 
    linear_combination<FieldT> result = lc.second * variable<FieldT>(0);
    for (const GLA::linear_term_t &lt : lc.first) {
        result = result + lt.second * variable<FieldT>(lt.first + 1);
    }
 
    return result;
}
 
r1cs_constraint_system<libff::Fr<libff::default_ec_pp>>
get_constraint_system_from_gadgetlib2(const gadgetlib2::Protoboard &pb)
{
    typedef libff::Fr<libff::default_ec_pp> FieldT;
    typedef gadgetlib2::GadgetLibAdapter GLA;
 
    r1cs_constraint_system<FieldT> result;
    const GLA adapter;
 
    GLA::protoboard_t converted_pb = adapter.convert(pb);
    for (const GLA::constraint_t &constr : converted_pb.first) {
        result.constraints.emplace_back(r1cs_constraint<FieldT>(
            convert_gadgetlib2_linear_combination(std::get<0>(constr)),
            convert_gadgetlib2_linear_combination(std::get<1>(constr)),
            convert_gadgetlib2_linear_combination(std::get<2>(constr))));
    }
    // The number of variables is the highest index created.
    // TODO: If there are multiple protoboards, or variables not assigned to a
    // protoboard, then getNextFreeIndex() is *not* the number of variables! See
    // also in get_variable_assignment_from_gadgetlib2.
    const size_t num_variables = GLA::getNextFreeIndex();
    result.primary_input_size = pb.numInputs();
    result.auxiliary_input_size = num_variables - pb.numInputs();
    return result;
}
 
r1cs_variable_assignment<libff::Fr<libff::default_ec_pp>>
get_variable_assignment_from_gadgetlib2(const gadgetlib2::Protoboard &pb)
{
    typedef libff::Fr<libff::default_ec_pp> FieldT;
    typedef gadgetlib2::GadgetLibAdapter GLA;
 
    // The number of variables is the highest index created. This is also the
    // required size for the assignment vector.
    // TODO: If there are multiple protoboards, or variables not assigned to a
    // protoboard, then getNextFreeIndex() is *not* the number of variables! See
    // also in get_constraint_system_from_gadgetlib2.
    const size_t num_vars = GLA::getNextFreeIndex();
    const GLA adapter;
    r1cs_variable_assignment<FieldT> result(num_vars, FieldT::zero());
    VariableAssignment assignment = pb.assignment();
 
    // Go over all assigned values of the protoboard, from every variable-value
    // pair, put the value in the variable.index place of the new assignment.
    for (VariableAssignment::iterator iter = assignment.begin();
         iter != assignment.end();
         ++iter) {
        result[GLA::getVariableIndex(iter->first)] =
            adapter.convert(iter->second);
    }
 
    return result;
}
 
} // namespace libsnark