Address review comments

src/plonk/keygen.rs

@@ -199,9 +199,11 @@ impl<F: Field> Assignment<F> for Assembly<F> {
     }
 }
 
+// This code also appears in `keygen`. We duplicate it here for simplicity of the
+// function body.
 fn k_from_circuit<F: Ord + Field + FromUniformBytes<64>, C: Circuit<F>>(circuit: &C) -> u32 {
     // TODO: We could optimize the order here.
-    (3..25)
+    (1..25)
         .find(|k| {
             let n = 2usize.pow(*k);
 

src/poly/commitment.rs

@@ -22,15 +22,14 @@ pub trait PolynomialCommitmentScheme<F: PrimeField>: Clone + Debug {
     /// Generates the parameters of the polynomial commitment scheme
     fn gen_params(k: u32) -> Self::Parameters;
 
-    /// Generate the `VerifierParameters` from `Parameters`
-    fn v_params_from_params(params: &Self::Parameters) -> Self::VerifierParameters;
+    /// Extract the `VerifierParameters` from `Parameters`
+    fn get_verifier_params(params: &Self::Parameters) -> Self::VerifierParameters;
 
     /// Commit to a polynomial in coefficient form
     fn commit(params: &Self::Parameters, polynomial: &Polynomial<F, Coeff>) -> Self::Commitment;
 
-    /// Commit to a polynomial using its evaluations over the $2^k$ size
-    /// evaluation domain. The commitment will be blinded by the blinding factor
-    /// `r`.
+    /// Commit to a polynomial expressed in Lagrange evaluations form (over the underlying domain
+    /// specified in params).
     fn commit_lagrange(
         params: &Self::Parameters,
         poly: &Polynomial<F, LagrangeCoeff>,
@@ -66,10 +65,11 @@ pub trait Guard<F: PrimeField, CS: PolynomialCommitmentScheme<F>>: Sized {
     /// Finalize a batch of verification guards
     fn batch_verify<'a, I, J>(guards: I, params: J) -> Result<(), Error>
     where
-        I: IntoIterator<Item = Self>,
-        J: IntoIterator<Item = &'a CS::VerifierParameters>,
+        I: ExactSizeIterator<Item = Self>,
+        J: ExactSizeIterator<Item = &'a CS::VerifierParameters>,
         CS::VerifierParameters: 'a,
     {
+        assert_eq!(guards.len(), params.len());
         guards
             .into_iter()
             .zip(params)

src/poly/kzg/mod.rs

@@ -46,7 +46,7 @@ where
         ParamsKZG::unsafe_setup(k, OsRng)
     }
 
-    fn v_params_from_params(params: &Self::Parameters) -> Self::VerifierParameters {
+    fn get_verifier_params(params: &Self::Parameters) -> Self::VerifierParameters {
         params.verifier_params()
     }