simple_example.tcc

Go to the documentation of this file.

/** @file
 *****************************************************************************
 * @author     This file is part of libsnark, developed by SCIPR Lab
 *             and contributors (see AUTHORS).
 * @copyright  MIT license (see LICENSE file)
 *****************************************************************************/
 
#ifndef SIMPLE_EXAMPLE_TCC_
#define SIMPLE_EXAMPLE_TCC_
 
#include <libsnark/gadgetlib1/gadgets/basic_gadgets.hpp>
 
namespace libsnark
{
 
/* NOTE: all examples here actually generate one constraint less to account for
 * soundness constraint in QAP */
 
template<typename FieldT>
r1cs_example<FieldT> gen_r1cs_example_from_protoboard(
    const size_t num_constraints)
{
    const size_t new_num_constraints = num_constraints - 1;
 
    /* construct dummy example: inner products of two vectors */
    protoboard<FieldT> pb;
    pb_variable_array<FieldT> A;
    pb_variable_array<FieldT> B;
    pb_variable<FieldT> res;
 
    // the variables on the protoboard are (ONE (constant 1 term), res, A[0],
    // ..., A[num_constraints-1], B[0], ..., B[num_constraints-1])
    res.allocate(pb, "res");
    A.allocate(pb, new_num_constraints, "A");
    B.allocate(pb, new_num_constraints, "B");
 
    inner_product_gadget<FieldT> compute_inner_product(
        pb, A, B, res, "compute_inner_product");
    compute_inner_product.generate_r1cs_constraints();
 
    /* fill in random example */
    for (size_t i = 0; i < new_num_constraints; ++i) {
        pb.val(A[i]) = FieldT::random_element();
        pb.val(B[i]) = FieldT::random_element();
    }
 
    compute_inner_product.generate_r1cs_witness();
    return r1cs_example<FieldT>(
        pb.get_constraint_system(), pb.primary_input(), pb.auxiliary_input());
}
 
} // namespace libsnark
#endif // R1CS_EXAMPLES_TCC_