From e0c488a21401095ca68d35a922f885f7ce39ec3d Mon Sep 17 00:00:00 2001
From: Fletcher Haynes <fletcher@capitalprawn.com>
Date: Thu, 13 Sep 2018 11:53:14 -0700
Subject: [PATCH] Adds a few more benchmarks for poly operators. Changed
 benchmarks to use a seeded rng for reproducibility.

---
 benches/bench.rs | 53 ++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 45 insertions(+), 8 deletions(-)

diff --git a/benches/bench.rs b/benches/bench.rs
index 36feaf1..bc67fdb 100644
--- a/benches/bench.rs
+++ b/benches/bench.rs
@@ -8,13 +8,16 @@ use criterion::Criterion;
 use pairing::bls12_381::Fr;
 use threshold_crypto::poly::Poly;
 
+const TEST_DEGREES: [usize; 4] = [5, 10, 20, 40];
+const RNG_SEED: [u32; 4] = [1, 2, 3, 4];
+
 mod poly_benches {
     use super::*;
-    use rand::Rng;
+    use rand::{Rng, SeedableRng, XorShiftRng};
 
-    // Benchmarks multiplication of two polynomials.
+    /// Benchmarks multiplication of two polynomials.
     fn multiplication(c: &mut Criterion) {
-        let mut rng = rand::thread_rng();
+        let mut rng = XorShiftRng::from_seed(RNG_SEED);
         c.bench_function_over_inputs(
             "Polynomial multiplication",
             move |b, &&deg| {
@@ -25,27 +28,61 @@ mod poly_benches {
                 };
                 b.iter_with_setup(rand_factors, |(lhs, rhs)| &lhs * &rhs)
             },
-            &[5, 10, 20, 40],
+            &TEST_DEGREES,
         );
     }
 
-    // Benchmarks Lagrange interpolation for a polynomial.
+    /// Benchmarks subtraction of two polynomials
+    fn subtraction(c: &mut Criterion) {
+        let mut rng = XorShiftRng::from_seed(RNG_SEED);
+        c.bench_function_over_inputs(
+            "Polynomial subtraction",
+            move |b, &&deg| {
+                let rand_factors = || {
+                    let lhs = Poly::random(deg, &mut rng);
+                    let rhs = Poly::random(deg, &mut rng);
+                    (lhs, rhs)
+                };
+                b.iter_with_setup(rand_factors, |(lhs, rhs)| &lhs - &rhs)
+            },
+            &TEST_DEGREES,
+        );
+    }
+
+    /// Benchmarks addition of two polynomials
+    fn addition(c: &mut Criterion) {
+        let mut rng = XorShiftRng::from_seed(RNG_SEED);
+        c.bench_function_over_inputs(
+            "Polynomial addition",
+            move |b, &&deg| {
+                let rand_factors = || {
+                    let lhs = Poly::random(deg, &mut rng);
+                    let rhs = Poly::random(deg, &mut rng);
+                    (lhs, rhs)
+                };
+                b.iter_with_setup(rand_factors, |(lhs, rhs)| &lhs + &rhs)
+            },
+            &TEST_DEGREES,
+        );
+    }
+
+    /// Benchmarks Lagrange interpolation for a polynomial.
     fn interpolate(c: &mut Criterion) {
-        let mut rng = rand::thread_rng();
+        let mut rng = XorShiftRng::from_seed(RNG_SEED);
         c.bench_function_over_inputs(
             "Polynomial interpolation",
             move |b, &&deg| {
                 let rand_samples = || (0..=deg).map(|i| (i, rng.gen::<Fr>())).collect::<Vec<_>>();
                 b.iter_with_setup(rand_samples, Poly::interpolate)
             },
-            &[5, 10, 20, 40],
+            &TEST_DEGREES,
         );
     }
 
     criterion_group!{
         name = poly_benches;
         config = Criterion::default();
-        targets = multiplication, interpolate,
+        targets = multiplication, interpolate, addition, subtraction,
     }
 }