From 80216d5931cb07b59bc781f469f1b36609ff1104 Mon Sep 17 00:00:00 2001
From: Jay White <JayWhite2357@users.noreply.github.com>
Date: Wed, 11 Dec 2024 13:01:36 -0500
Subject: [PATCH] perf: avoid cloning sumcheck terms

---
 .../base/polynomial/multilinear_extension.rs    | 17 ++++++++---------
 .../sql/proof/composite_polynomial_builder.rs   | 10 ++++++----
 .../src/sql/proof/make_sumcheck_state.rs        |  4 ++--
 3 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/crates/proof-of-sql/src/base/polynomial/multilinear_extension.rs b/crates/proof-of-sql/src/base/polynomial/multilinear_extension.rs
index a5fe4481c..ca361dae4 100644
--- a/crates/proof-of-sql/src/base/polynomial/multilinear_extension.rs
+++ b/crates/proof-of-sql/src/base/polynomial/multilinear_extension.rs
@@ -1,5 +1,5 @@
 use crate::base::{database::Column, if_rayon, scalar::Scalar, slice_ops};
-use alloc::{rc::Rc, vec::Vec};
+use alloc::vec::Vec;
 use core::{ffi::c_void, fmt::Debug};
 use num_traits::Zero;
 #[cfg(feature = "rayon")]
@@ -15,7 +15,7 @@ pub trait MultilinearExtension<S: Scalar>: Debug {
     fn mul_add(&self, res: &mut [S], multiplier: &S);
 
     /// convert the MLE to a form that can be used in sumcheck
-    fn to_sumcheck_term(&self, num_vars: usize) -> Rc<Vec<S>>;
+    fn to_sumcheck_term(&self, num_vars: usize) -> Vec<S>;
 
     /// pointer to identify the slice forming the MLE
     fn id(&self) -> (*const c_void, usize);
@@ -42,18 +42,17 @@ where
         slice_ops::mul_add_assign(res, *multiplier, &slice_ops::slice_cast(self));
     }
 
-    fn to_sumcheck_term(&self, num_vars: usize) -> Rc<Vec<S>> {
+    fn to_sumcheck_term(&self, num_vars: usize) -> Vec<S> {
         let values = self;
         let n = 1 << num_vars;
         assert!(n >= values.len());
-        let scalars = if_rayon!(values.par_iter(), values.iter())
+        if_rayon!(values.par_iter(), values.iter())
             .map(Into::into)
             .chain(if_rayon!(
                 rayon::iter::repeatn(Zero::zero(), n - values.len()),
                 itertools::repeat_n(Zero::zero(), n - values.len())
             ))
-            .collect();
-        Rc::new(scalars)
+            .collect()
     }
 
     fn id(&self) -> (*const c_void, usize) {
@@ -72,7 +71,7 @@ macro_rules! slice_like_mle_impl {
             (&self[..]).mul_add(res, multiplier)
         }
 
-        fn to_sumcheck_term(&self, num_vars: usize) -> Rc<Vec<S>> {
+        fn to_sumcheck_term(&self, num_vars: usize) -> Vec<S> {
             (&self[..]).to_sumcheck_term(num_vars)
         }
 
@@ -125,7 +124,7 @@ impl<S: Scalar> MultilinearExtension<S> for &Column<'_, S> {
         }
     }
 
-    fn to_sumcheck_term(&self, num_vars: usize) -> Rc<Vec<S>> {
+    fn to_sumcheck_term(&self, num_vars: usize) -> Vec<S> {
         match self {
             Column::Boolean(c) => c.to_sumcheck_term(num_vars),
             Column::Scalar(c) | Column::VarChar((_, c)) | Column::Decimal75(_, _, c) => {
@@ -163,7 +162,7 @@ impl<S: Scalar> MultilinearExtension<S> for Column<'_, S> {
         (&self).mul_add(res, multiplier);
     }
 
-    fn to_sumcheck_term(&self, num_vars: usize) -> Rc<Vec<S>> {
+    fn to_sumcheck_term(&self, num_vars: usize) -> Vec<S> {
         (&self).to_sumcheck_term(num_vars)
     }
 
diff --git a/crates/proof-of-sql/src/sql/proof/composite_polynomial_builder.rs b/crates/proof-of-sql/src/sql/proof/composite_polynomial_builder.rs
index 62346bb1e..e554cbe85 100644
--- a/crates/proof-of-sql/src/sql/proof/composite_polynomial_builder.rs
+++ b/crates/proof-of-sql/src/sql/proof/composite_polynomial_builder.rs
@@ -32,7 +32,7 @@ impl<S: Scalar> CompositePolynomialBuilder<S> {
             fr_multiplicands_degree1: vec![Zero::zero(); fr.len()],
             fr_multiplicands_rest: vec![],
             zerosum_multiplicands: vec![],
-            fr: fr.to_sumcheck_term(num_sumcheck_variables),
+            fr: fr.to_sumcheck_term(num_sumcheck_variables).into(),
             mles: IndexMap::default(),
         }
     }
@@ -89,8 +89,8 @@ impl<S: Scalar> CompositePolynomialBuilder<S> {
                 deduplicated_terms.push(cached_term.clone());
             } else {
                 let new_term = term.to_sumcheck_term(self.num_sumcheck_variables);
-                self.mles.insert(id, new_term.clone());
-                deduplicated_terms.push(new_term);
+                self.mles.insert(id, new_term.clone().into());
+                deduplicated_terms.push(new_term.into());
             }
         }
         deduplicated_terms
@@ -103,7 +103,9 @@ impl<S: Scalar> CompositePolynomialBuilder<S> {
         res.add_product(
             [
                 self.fr.clone(),
-                (&self.fr_multiplicands_degree1).to_sumcheck_term(self.num_sumcheck_variables),
+                (&self.fr_multiplicands_degree1)
+                    .to_sumcheck_term(self.num_sumcheck_variables)
+                    .into(),
             ],
             One::one(),
         );
diff --git a/crates/proof-of-sql/src/sql/proof/make_sumcheck_state.rs b/crates/proof-of-sql/src/sql/proof/make_sumcheck_state.rs
index 3f494f2bb..58dc90c22 100644
--- a/crates/proof-of-sql/src/sql/proof/make_sumcheck_state.rs
+++ b/crates/proof-of-sql/src/sql/proof/make_sumcheck_state.rs
@@ -98,11 +98,11 @@ impl<'a, S: Scalar> FlattenedMLEBuilder<'a, S> {
     fn flattened_ml_extensions(self) -> Vec<Vec<S>> {
         self.entrywise_multipliers
             .into_iter()
-            .map(|mle| (&mle).to_sumcheck_term(self.num_vars).as_ref().clone())
+            .map(|mle| (&mle).to_sumcheck_term(self.num_vars))
             .chain(
                 self.all_ml_extensions
                     .iter()
-                    .map(|mle| mle.to_sumcheck_term(self.num_vars).as_ref().clone()),
+                    .map(|mle| mle.to_sumcheck_term(self.num_vars)),
             )
             .collect()
     }