Add benchmarks for shared double-and-add

Cargo.toml

@@ -20,6 +20,13 @@ publish = false
 [package.metadata.docs.rs]
 rustdoc-args = [ "--html-in-header", "katex-header.html" ]
 
+[dev-dependencies]
+criterion = "0.3"
+
+[[bench]]
+name = "plonk"
+harness = false
+
 [dependencies]
 subtle = "2.2.1"
 crossbeam-utils = "0.7"

benches/plonk.rs

@@ -0,0 +1,42 @@
+#[macro_use]
+extern crate criterion;
+
+extern crate halo2;
+use crate::arithmetic::{small_multiexp, EqAffine, Field, Fp, Fq};
+use crate::poly::commitment::Params;
+use crate::transcript::DummyHash;
+use halo2::*;
+
+use criterion::{black_box, Criterion};
+
+fn criterion_benchmark(c: &mut Criterion) {
+    // small multiexp
+    {
+        let params: Params<EqAffine> = Params::new::<DummyHash<Fq>>(5);
+        let g = &mut params.get_g();
+        let len = g.len() / 2;
+        let (g_lo, g_hi) = g.split_at_mut(len);
+
+        let coeff_1 = Fp::random();
+        let coeff_2 = Fp::random();
+
+        c.bench_function("shared double-and-add", |b| {
+            b.iter(|| {
+                for (g_lo, g_hi) in g_lo.iter().zip(g_hi.iter()) {
+                    small_multiexp(&[black_box(coeff_1), black_box(coeff_2)], &[*g_lo, *g_hi]);
+                }
+            })
+        });
+
+        c.bench_function("double-and-add", |b| {
+            b.iter(|| {
+                for (g_lo, g_hi) in g_lo.iter().zip(g_hi.iter()) {
+                    let _ = ((*g_lo) * coeff_1) + &((*g_hi) * coeff_2);
+                }
+            })
+        });
+    }
+}
+
+criterion_group!(benches, criterion_benchmark);
+criterion_main!(benches);

src/poly/commitment.rs

@@ -261,6 +261,11 @@ impl<C: CurveAffine> Params<C> {
             other_bases,
         }
     }
+
+    /// Getter for g generators
+    pub fn get_g(&self) -> Vec<C> {
+        self.g.clone()
+    }
 }
 
 /// A guard returned by the verifier