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Merged
maramihali merged 17 commits into from
Oct 23, 2024
Merged

feat: translator on Shplemini #9329

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5c34ef3
translator flavor tiny cleanup
Oct 2, 2024
d10e181
fix test crashing
Oct 3, 2024
0e0bd86
more cleanup
Oct 3, 2024
68cd5a3
start
Oct 3, 2024
11cf6ba
I have advanced, still not fully working
Oct 8, 2024
8a147c2
still trying
Oct 9, 2024
eb2197e
stuff
Oct 9, 2024
48ab877
it works
Oct 14, 2024
cfb7b98
translator on shplemini
Oct 21, 2024
5491b58
cleanup and explanations
Oct 22, 2024
0ef5992
Merge remote-tracking branch 'origin/master' into mm/translator-on-sh…
Oct 22, 2024
8ea510a
cleanup
Oct 22, 2024
60dd83c
a bit more cleanup
Oct 22, 2024
dca6d62
Merge branch 'master' into mm/translator-on-shplemini
Oct 22, 2024
27f43e6
add some more comments
Oct 23, 2024
7fbefa0
Merge remote-tracking branch 'refs/remotes/origin/mm/translator-on-sh…
Oct 23, 2024
6a0eabe
Merge branch 'master' into mm/translator-on-shplemini
Oct 23, 2024
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161 changes: 90 additions & 71 deletions barretenberg/cpp/src/barretenberg/commitment_schemes/gemini/gemini.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -103,19 +103,25 @@ template <typename Curve> class GeminiProver_ {
static std::vector<Polynomial> compute_fold_polynomials(const size_t log_N,
std::span<const Fr> multilinear_challenge,
Polynomial&& batched_unshifted,
Polynomial&& batched_to_be_shifted);
Polynomial&& batched_to_be_shifted,
Polynomial&& batched_concatenated = {});

static std::vector<Claim> compute_fold_polynomial_evaluations(const size_t log_N,
std::vector<Polynomial>&& fold_polynomials,
const Fr& r_challenge);
static std::vector<Claim> compute_fold_polynomial_evaluations(
const size_t log_N,
std::vector<Polynomial>&& fold_polynomials,
const Fr& r_challenge,
std::vector<Polynomial>&& batched_groups_to_be_concatenated = {});

template <typename Transcript>
static std::vector<Claim> prove(const Fr circuit_size,
RefSpan<Polynomial> f_polynomials,
RefSpan<Polynomial> g_polynomials,
std::span<Fr> multilinear_challenge,
const std::shared_ptr<CommitmentKey<Curve>>& commitment_key,
const std::shared_ptr<Transcript>& transcript);
const std::shared_ptr<Transcript>& transcript,
RefSpan<Polynomial> concatenated_polynomials = {},
const std::vector<RefVector<Polynomial>>& groups_to_be_concatenated = {});

}; // namespace bb

template <typename Curve> class GeminiVerifier_ {
Expand All @@ -136,32 +142,38 @@ template <typename Curve> class GeminiVerifier_ {
* @return Fold polynomial opening claims: (r, A₀(r), C₀₊), (-r, A₀(-r), C₀₋), and
* (Cⱼ, Aⱼ(-r^{2ʲ}), -r^{2}), j = [1, ..., m-1]
*/
static std::vector<OpeningClaim<Curve>> reduce_verification(std::span<Fr> multilinear_challenge,
std::span<Fr> multilinear_evaluations,
RefSpan<GroupElement> unshifted_commitments,
RefSpan<GroupElement> to_be_shifted_commitments,
auto& transcript)
static std::vector<OpeningClaim<Curve>> reduce_verification(
std::span<Fr> multilinear_challenge,
RefSpan<Fr> unshifted_evaluations,
RefSpan<Fr> shifted_evaluations,
RefSpan<Commitment> unshifted_commitments,
RefSpan<Commitment> to_be_shifted_commitments,
auto& transcript,
const std::vector<RefVector<Commitment>>& concatenation_group_commitments = {},
RefSpan<Fr> concatenated_evaluations = {})

{
const size_t num_variables = multilinear_challenge.size();

const size_t N = 1 << num_variables;

Fr rho = transcript->template get_challenge<Fr>("rho");
std::vector<Fr> rhos = gemini::powers_of_rho(rho, multilinear_evaluations.size());

GroupElement batched_commitment_unshifted = GroupElement::zero();
GroupElement batched_commitment_to_be_shifted = GroupElement::zero();

Fr batched_evaluation = Fr::zero();
for (size_t i = 0; i < multilinear_evaluations.size(); ++i) {
batched_evaluation += multilinear_evaluations[i] * rhos[i];
Fr batched_evaluation = Fr(0);
Fr batching_scalar = Fr(1);
for (auto [eval, comm] : zip_view(unshifted_evaluations, unshifted_commitments)) {
batched_evaluation += eval * batching_scalar;
batched_commitment_unshifted += comm * batching_scalar;
batching_scalar *= rho;
}

const size_t num_unshifted = unshifted_commitments.size();
const size_t num_to_be_shifted = to_be_shifted_commitments.size();
for (size_t i = 0; i < num_unshifted; i++) {
batched_commitment_unshifted += unshifted_commitments[i] * rhos[i];
}
for (size_t i = 0; i < num_to_be_shifted; i++) {
batched_commitment_to_be_shifted += to_be_shifted_commitments[i] * rhos[num_unshifted + i];
for (auto [eval, comm] : zip_view(shifted_evaluations, to_be_shifted_commitments)) {
batched_evaluation += eval * batching_scalar;
batched_commitment_to_be_shifted += comm * batching_scalar;
batching_scalar *= rho;
}

// Get polynomials Fold_i, i = 1,...,m-1 from transcript
Expand All @@ -173,22 +185,71 @@ template <typename Curve> class GeminiVerifier_ {

// Get evaluations a_i, i = 0,...,m-1 from transcript
const std::vector<Fr> evaluations = get_gemini_evaluations(num_variables, transcript);

// C₀_r_pos = ∑ⱼ ρʲ⋅[fⱼ] + r⁻¹⋅∑ⱼ ρᵏ⁺ʲ [gⱼ], the commitment to A₀₊
// C₀_r_neg = ∑ⱼ ρʲ⋅[fⱼ] - r⁻¹⋅∑ⱼ ρᵏ⁺ʲ [gⱼ], the commitment to A₀₋
GroupElement C0_r_pos = batched_commitment_unshifted;
GroupElement C0_r_neg = batched_commitment_unshifted;

Fr r_inv = r.invert();
if (!batched_commitment_to_be_shifted.is_point_at_infinity()) {
batched_commitment_to_be_shifted = batched_commitment_to_be_shifted * r_inv;
C0_r_pos += batched_commitment_to_be_shifted;
C0_r_neg -= batched_commitment_to_be_shifted;
}

// If verifying the opening for the translator VM, we reconstruct the commitment of the batched concatenated
// polynomials, partially evaluated in r and -r, using the commitments in the concatenation groups and add their
// contribution as well to to C₀_r_pos and C₀_r_neg
ASSERT(concatenated_evaluations.size() == concatenation_group_commitments.size());
if (!concatenation_group_commitments.empty()) {
size_t concatenation_group_size = concatenation_group_commitments[0].size();
// The "real" size of polynomials in concatenation groups (i.e. the number of non-zero values)
const size_t mini_circuit_size = N / concatenation_group_size;
Fr current_r_shift_pos = Fr(1);
Fr current_r_shift_neg = Fr(1);
const Fr r_pow_minicircuit = r.pow(mini_circuit_size);
const Fr r_neg_pow_minicircuit = (-r).pow(mini_circuit_size);
std::vector<Fr> r_shifts_pos;
std::vector<Fr> r_shifts_neg;
for (size_t i = 0; i < concatenation_group_size; ++i) {
r_shifts_pos.emplace_back(current_r_shift_pos);
r_shifts_neg.emplace_back(current_r_shift_neg);
current_r_shift_pos *= r_pow_minicircuit;
current_r_shift_neg *= r_neg_pow_minicircuit;
}
size_t j = 0;
GroupElement batched_concatenated_pos = GroupElement::zero();
GroupElement batched_concatenated_neg = GroupElement::zero();
for (auto& concatenation_group_commitment : concatenation_group_commitments) {
// Compute the contribution from each group j of commitments Gⱼ = {C₀, C₁, C₂, C₃, ...}
// where s = mini_circuit_size as
// C₀_r_pos += ∑ᵢ ρᵏ⁺ᵐ⁺ʲ⋅ rⁱˢ ⋅ Cᵢ
// C₀_r_neg += ∑ᵢ ρᵏ⁺ᵐ⁺ʲ⋅ (-r)ⁱˢ ⋅ Cᵢ
for (size_t i = 0; i < concatenation_group_size; ++i) {
batched_concatenated_pos += concatenation_group_commitment[i] * batching_scalar * r_shifts_pos[i];
batched_concatenated_neg += concatenation_group_commitment[i] * batching_scalar * r_shifts_neg[i];
}
batched_evaluation += concatenated_evaluations[j] * batching_scalar;
batching_scalar *= rho;
j++;
}

// Add the contributions from concatenation groups to get the final [A₀₊] and [A₀₋]
C0_r_pos += batched_concatenated_pos;
C0_r_neg += batched_concatenated_neg;
}

// Compute evaluation A₀(r)
auto a_0_pos = compute_gemini_batched_univariate_evaluation(
num_variables, batched_evaluation, multilinear_challenge, r_squares, evaluations);

// C₀_r_pos = ∑ⱼ ρʲ⋅[fⱼ] + r⁻¹⋅∑ⱼ ρᵏ⁺ʲ [gⱼ]
// C₀_r_pos = ∑ⱼ ρʲ⋅[fⱼ] - r⁻¹⋅∑ⱼ ρᵏ⁺ʲ [gⱼ]
auto [c0_r_pos, c0_r_neg] =
compute_simulated_commitments(batched_commitment_unshifted, batched_commitment_to_be_shifted, r);

std::vector<OpeningClaim<Curve>> fold_polynomial_opening_claims;
fold_polynomial_opening_claims.reserve(num_variables + 1);

// ( [A₀₊], r, A₀(r) )
fold_polynomial_opening_claims.emplace_back(OpeningClaim<Curve>{ { r, a_0_pos }, c0_r_pos });
fold_polynomial_opening_claims.emplace_back(OpeningClaim<Curve>{ { r, a_0_pos }, C0_r_pos });
// ( [A₀₋], -r, A₀(-r) )
fold_polynomial_opening_claims.emplace_back(OpeningClaim<Curve>{ { -r, evaluations[0] }, c0_r_neg });
fold_polynomial_opening_claims.emplace_back(OpeningClaim<Curve>{ { -r, evaluations[0] }, C0_r_neg });
for (size_t l = 0; l < num_variables - 1; ++l) {
// ([A₀₋], −r^{2ˡ}, Aₗ(−r^{2ˡ}) )
fold_polynomial_opening_claims.emplace_back(
Expand Down Expand Up @@ -283,48 +344,6 @@ template <typename Curve> class GeminiVerifier_ {

return batched_eval_accumulator;
}
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@maramihali maramihali Oct 22, 2024

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The native branch of this code was moved to reduce verification to simplify my work. Basically GeminiVerifier is only going to be used for debugging, in the native universe, and this seemed the simplest approach


/**
* @brief Computes two commitments to A₀ partially evaluated in r and -r.
*
* @param batched_commitment_unshifted batched commitment to non-shifted polynomials
* @param batched_commitment_to_be_shifted batched commitment to to-be-shifted polynomials
* @param r evaluation point at which we have partially evaluated A₀ at r and -r.
* @return std::pair<Commitment, Commitment> c0_r_pos, c0_r_neg
*/
static std::pair<GroupElement, GroupElement> compute_simulated_commitments(
GroupElement& batched_commitment_unshifted, GroupElement& batched_commitment_to_be_shifted, Fr r)
{
// C₀ᵣ₊ = [F] + r⁻¹⋅[G]
GroupElement C0_r_pos;
// C₀ᵣ₋ = [F] - r⁻¹⋅[G]
GroupElement C0_r_neg;
Fr r_inv = r.invert(); // r⁻¹

// If in a recursive setting, perform a batch mul. Otherwise, accumulate directly.
// TODO(#673): The following if-else represents the stldib/native code paths. Once the "native" verifier is
// achieved through a builder Simulator, the stdlib codepath should become the only codepath.
if constexpr (Curve::is_stdlib_type) {
std::vector<GroupElement> commitments = { batched_commitment_unshifted, batched_commitment_to_be_shifted };
auto builder = r.get_context();
auto one = Fr(builder, 1);
// TODO(#707): these batch muls include the use of 1 as a scalar. This is handled appropriately as a non-mul
// (add-accumulate) in the goblin batch_mul but is done inefficiently as a scalar mul in the conventional
// emulated batch mul.
C0_r_pos = GroupElement::batch_mul(commitments, { one, r_inv });
C0_r_neg = GroupElement::batch_mul(commitments, { one, -r_inv });
} else {
C0_r_pos = batched_commitment_unshifted;
C0_r_neg = batched_commitment_unshifted;
if (!batched_commitment_to_be_shifted.is_point_at_infinity()) {
batched_commitment_to_be_shifted = batched_commitment_to_be_shifted * r_inv;
C0_r_pos += batched_commitment_to_be_shifted;
C0_r_neg -= batched_commitment_to_be_shifted;
}
}

return { C0_r_pos, C0_r_neg };
}
};

} // namespace bb
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