translation_evaluations.hpp

Go to the documentation of this file.

// === AUDIT STATUS ===
// internal:    { status: not started, auditors: [], date: YYYY-MM-DD }
// external_1:  { status: not started, auditors: [], date: YYYY-MM-DD }
// external_2:  { status: not started, auditors: [], date: YYYY-MM-DD }
// =====================
 
#pragma once
#include "barretenberg/common/ref_array.hpp"
#include "barretenberg/constants.hpp"
#include "barretenberg/ecc/curves/bn254/fq.hpp"
#include "barretenberg/ecc/fields/field_conversion.hpp"
 
namespace bb {
template <typename BF> struct TranslationEvaluations_ {
    BF op, Px, Py, z1, z2;
    static size_t size() { return field_conversion::calc_num_bn254_frs<BF>() * NUM_TRANSLATION_EVALUATIONS; }
 
    RefArray<BF, NUM_TRANSLATION_EVALUATIONS> get_all() { return { op, Px, Py, z1, z2 }; }
 
    std::array<std::string, NUM_TRANSLATION_EVALUATIONS> labels = {
        "Translation:op", "Translation:Px", "Translation:Py", "Translation:z1", "Translation:z2"
    };
    ;
 
    MSGPACK_FIELDS(op, Px, Py, z1, z2);
};
 
template <typename FF>
static void shift_translation_masking_term_eval(const FF& evaluation_challenge_x, FF& translation_masking_term_eval)
{
    // This method is only invoked within Goblin, which runs ECCVM with a fixed size.
    static constexpr size_t LOG_MASKING_OFFSET = numeric::get_msb(NUM_DISABLED_ROWS_IN_SUMCHECK);
    static_assert(1UL << LOG_MASKING_OFFSET == NUM_DISABLED_ROWS_IN_SUMCHECK, "MASKING_OFFSET must be a power of 2");
 
    FF x_to_num_disabled_rows = evaluation_challenge_x;
    for (size_t idx = 0; idx < LOG_MASKING_OFFSET; idx++) {
        x_to_num_disabled_rows = x_to_num_disabled_rows.sqr();
    }
 
    FF x_to_circuit_size = x_to_num_disabled_rows;
 
    for (size_t idx = LOG_MASKING_OFFSET; idx < CONST_ECCVM_LOG_N; idx++) {
        x_to_circuit_size = x_to_circuit_size.sqr();
    }
 
    // Update `translation_masking_term_eval`
    translation_masking_term_eval *= x_to_circuit_size;
    translation_masking_term_eval *= x_to_num_disabled_rows.invert();
};
} // namespace bb