Parallelize TE to SW mapping (#15)

Cargo.toml

@@ -13,6 +13,7 @@ ark-std = { version = "0.4.0", default-features = false }
 ark-serialize = { version = "0.4.2", default-features = false }
 rand_core = { version = "0.6.4", default-features = false, optional = true }
 rand_chacha = { version = "0.3.1", default-features = false }
+rayon = { version = "1.10", default-features = false, optional = true }
 zeroize = { version = "1.7.0", default-features = false }
 hmac = {version = "0.12.1", default-features = false, optional = true }
 digest = { version = "0.10.7", default-features = false }
@@ -60,6 +61,7 @@ parallel = [
   "ark-std/parallel",
   "ring-proof?/parallel",
   "fflonk?/parallel",
+  "rayon",
 ]
 ring = [
   "bandersnatch",

src/ring.rs

@@ -2,6 +2,9 @@ use crate::*;
 use ark_ec::short_weierstrass::SWCurveConfig;
 use pedersen::{PedersenSuite, Proof as PedersenProof};
 
+#[cfg(feature = "parallel")]
+use rayon::prelude::*;
+
 pub trait RingSuite: PedersenSuite {
     type Pairing: ark_ec::pairing::Pairing<ScalarField = BaseField<Self>>;
 
@@ -165,12 +168,18 @@ where
     }
 
     pub fn prover_key(&self, pks: &[AffinePoint<S>]) -> ProverKey<S> {
+        #[cfg(feature = "parallel")]
+        let pks = pks.par_iter().map(|p| p.into_sw()).collect();
+        #[cfg(not(feature = "parallel"))]
         let pks = pks.iter().map(|p| p.into_sw()).collect();
         ring_proof::index(self.pcs_params.clone(), &self.piop_params, pks).0
     }
 
     pub fn verifier_key(&self, pks: &[AffinePoint<S>]) -> VerifierKey<S> {
-        let pks: Vec<_> = pks.iter().map(|p| p.into_sw()).collect();
+        #[cfg(feature = "parallel")]
+        let pks = pks.par_iter().map(|p| p.into_sw()).collect();
+        #[cfg(not(feature = "parallel"))]
+        let pks = pks.iter().map(|p| p.into_sw()).collect();
         ring_proof::index(self.pcs_params.clone(), &self.piop_params, pks).1
     }