Refactor BaseFold hashing benchmark. (#556)

Extract a small independent change from #294

Co-authored-by: Ming <[email protected]>

mpcs/benches/hashing.rs

@@ -5,28 +5,19 @@ use goldilocks::Goldilocks;
 use mpcs::util::hash::{Digest, hash_two_digests};
 use poseidon::poseidon_hash::PoseidonHash;
 
+fn random_ceno_goldy() -> Goldilocks {
+    Goldilocks::random(&mut test_rng())
+}
 pub fn criterion_benchmark(c: &mut Criterion) {
-    let left = Digest(
-        vec![Goldilocks::random(&mut test_rng()); 4]
-            .try_into()
-            .unwrap(),
-    );
-    let right = Digest(
-        vec![Goldilocks::random(&mut test_rng()); 4]
-            .try_into()
-            .unwrap(),
-    );
+    let left = Digest(vec![random_ceno_goldy(); 4].try_into().unwrap());
+    let right = Digest(vec![random_ceno_goldy(); 4].try_into().unwrap());
     c.bench_function("ceno hash 2 to 1", |bencher| {
         bencher.iter(|| hash_two_digests(&left, &right))
     });
 
-    let values = (0..60)
-        .map(|_| Goldilocks::random(&mut test_rng()))
-        .collect::<Vec<_>>();
+    let values = (0..60).map(|_| random_ceno_goldy()).collect::<Vec<_>>();
     c.bench_function("ceno hash 60 to 1", |bencher| {
-        bencher.iter(|| {
-            PoseidonHash::hash_or_noop(&values);
-        })
+        bencher.iter(|| PoseidonHash::hash_or_noop(&values))
     });
 }