Method accumulate_commitments_and_values

poly-commit/src/marlin/mod.rs:109–148

Accumulate `commitments` and `values` according to the challenges produces by `challenge_gen`.

(
        commitments: impl IntoIterator<Item = &'a LabeledCommitment<marlin_pc::Commitment<E>>>,
        values: impl IntoIterator<Item = E::ScalarField>,
        sponge: &mut impl CryptographicSpong

    /// Accumulate `commitments` and `values` according to the challenges produces by `challenge_gen`.
    fn accumulate_commitments_and_values<'a>(
        commitments: impl IntoIterator<Item = &'a LabeledCommitment<marlin_pc::Commitment<E>>>,
        values: impl IntoIterator<Item = E::ScalarField>,
        sponge: &mut impl CryptographicSponge,
        vk: Option<&marlin_pc::VerifierKey<E>>,
    ) -> Result<(E::G1, E::ScalarField), Error> {
        let acc_time = start_timer!(|| "Accumulating commitments and values");
        let mut combined_comm = E::G1::zero();
        let mut combined_value = E::ScalarField::zero();
        for (labeled_commitment, value) in commitments.into_iter().zip(values) {
            let degree_bound = labeled_commitment.degree_bound();
            let commitment = labeled_commitment.commitment();
            assert_eq!(degree_bound.is_some(), commitment.shifted_comm.is_some());

            let challenge_i = sponge.squeeze_field_elements_with_sizes(&[CHALLENGE_SIZE])[0];

            combined_comm += &commitment.comm.0.mul(challenge_i);
            combined_value += &(value * &challenge_i);

            if let Some(degree_bound) = degree_bound {
                let challenge_i_1: E::ScalarField =
                    sponge.squeeze_field_elements_with_sizes(&[CHALLENGE_SIZE])[0];

                let shifted_comm = commitment.shifted_comm.as_ref().unwrap().0.into_group();

                let shift_power = vk
                    .unwrap()
                    .get_shift_power(degree_bound)
                    .ok_or(Error::UnsupportedDegreeBound(degree_bound))?;

                let mut adjusted_comm = shifted_comm - &shift_power.mul(value);

                adjusted_comm *= challenge_i_1;
                combined_comm += &adjusted_comm;
            }
        }

        end_timer!(acc_time);
        Ok((combined_comm, combined_value))
    }

    /// Combine and normalize a set of commitments
    fn combine_and_normalize<'a, D: Clone + Ord + Sync>(