Performance tweaks (#77)

src/circuit_builder.rs

@@ -21,7 +21,7 @@ use crate::plonk_common::PlonkPolynomials;
 use crate::polynomial::commitment::ListPolynomialCommitment;
 use crate::polynomial::polynomial::PolynomialValues;
 use crate::target::Target;
-use crate::util::{log2_strict, transpose};
+use crate::util::{log2_strict, transpose, transpose_poly_values};
 use crate::wire::Wire;
 
 pub struct CircuitBuilder<F: Extendable<D>, const D: usize> {
@@ -307,7 +307,7 @@ impl<F: Extendable<D>, const D: usize> CircuitBuilder<F, D> {
         let k_is = get_unique_coset_shifts(degree, self.config.num_routed_wires);
         let sigma_vecs = self.sigma_vecs(&k_is, &subgroup);
 
-        let constants_sigmas_vecs = [constant_vecs, sigma_vecs].concat();
+        let constants_sigmas_vecs = [constant_vecs, sigma_vecs.clone()].concat();
         let constants_sigmas_commitment = ListPolynomialCommitment::new(
             constants_sigmas_vecs,
             self.config.fri_config.rate_bits,
@@ -322,6 +322,7 @@ impl<F: Extendable<D>, const D: usize> CircuitBuilder<F, D> {
         let prover_only = ProverOnlyCircuitData {
             generators: self.generators,
             constants_sigmas_commitment,
+            sigmas: transpose_poly_values(sigma_vecs),
             subgroup,
             copy_constraints: self.copy_constraints,
             gate_instances: self.gate_instances,

src/circuit_data.rs

@@ -120,6 +120,8 @@ pub(crate) struct ProverOnlyCircuitData<F: Extendable<D>, const D: usize> {
     pub generators: Vec<Box<dyn WitnessGenerator<F>>>,
     /// Commitments to the constants polynomials and sigma polynomials.
     pub constants_sigmas_commitment: ListPolynomialCommitment<F>,
+    /// The transpose of the list of sigma polynomials.
+    pub sigmas: Vec<Vec<F>>,
     /// Subgroup of order `degree`.
     pub subgroup: Vec<F>,
     /// The circuit's copy constraints.

src/polynomial/commitment.rs

@@ -19,7 +19,6 @@ pub const SALT_SIZE: usize = 2;
 
 pub struct ListPolynomialCommitment<F: Field> {
     pub polynomials: Vec<PolynomialCoeffs<F>>,
-    pub values: Vec<PolynomialValues<F>>,
     pub merkle_tree: MerkleTree<F>,
     pub degree: usize,
     pub degree_log: usize,
@@ -40,7 +39,7 @@ impl<F: Field> ListPolynomialCommitment<F> {
             "to compute LDE"
         );
 
-        Self::new_from_data(polynomials, values, lde_values, degree, rate_bits, blinding)
+        Self::new_from_data(polynomials, lde_values, degree, rate_bits, blinding)
     }
 
     /// Creates a list polynomial commitment for the polynomials `polynomials`.
@@ -50,21 +49,16 @@ impl<F: Field> ListPolynomialCommitment<F> {
         blinding: bool,
     ) -> Self {
         let degree = polynomials[0].len();
-        let values = polynomials
-            .iter()
-            .map(|v| v.clone().fft())
-            .collect::<Vec<_>>();
         let lde_values = timed!(
             Self::lde_values(&polynomials, rate_bits, blinding),
             "to compute LDE"
         );
 
-        Self::new_from_data(polynomials, values, lde_values, degree, rate_bits, blinding)
+        Self::new_from_data(polynomials, lde_values, degree, rate_bits, blinding)
     }
 
     fn new_from_data(
         polynomials: Vec<PolynomialCoeffs<F>>,
-        values: Vec<PolynomialValues<F>>,
         lde_values: Vec<Vec<F>>,
         degree: usize,
         rate_bits: usize,
@@ -76,7 +70,6 @@ impl<F: Field> ListPolynomialCommitment<F> {
 
         Self {
             polynomials,
-            values,
             merkle_tree,
             degree,
             degree_log: log2_strict(degree),
@@ -108,9 +101,6 @@ impl<F: Field> ListPolynomialCommitment<F> {
             .collect()
     }
 
-    pub fn original_values(&self, index: usize) -> Vec<F> {
-        self.values.iter().map(|v| v.values[index]).collect()
-    }
     pub fn get_lde_values(&self, index: usize) -> &[F] {
         let index = reverse_bits(index, self.degree_log + self.rate_bits);
         let slice = &self.merkle_tree.leaves[index];

src/prover.rs

@@ -194,9 +194,7 @@ fn compute_z<F: Extendable<D>, const D: usize>(
         let x = subgroup[i - 1];
         let mut numerator = F::ONE;
         let mut denominator = F::ONE;
-        let s_sigmas = &prover_data
-            .constants_sigmas_commitment
-            .original_values(i - 1)[common_data.sigmas_range()];
+        let s_sigmas = &prover_data.sigmas[i - 1];
         for j in 0..common_data.config.num_routed_wires {
             let wire_value = witness.get_wire(i - 1, j);
             let k_i = k_is[j];