From e507a950374921cfbd5aa7e4b6707dc6db3c6040 Mon Sep 17 00:00:00 2001
From: Kenil shah <kenilshah1505@gmail.com>
Date: Tue, 31 Mar 2026 15:01:39 +0530
Subject: [PATCH] perf: pre-allocate HashMap and remove redundant intermediate
 Vec in multiproof

---
 ipa-multipoint/src/multiproof.rs | 28 ++++++++++------------------
 1 file changed, 10 insertions(+), 18 deletions(-)

diff --git a/ipa-multipoint/src/multiproof.rs b/ipa-multipoint/src/multiproof.rs
index d10b5a41..9c38c7be 100644
--- a/ipa-multipoint/src/multiproof.rs
+++ b/ipa-multipoint/src/multiproof.rs
@@ -48,7 +48,8 @@ fn group_prover_queries<'a>(
     challenges: &'a [Fr],
 ) -> FxHashMap<usize, Vec<(&'a ProverQuery, &'a Fr)>> {
     // We want to group all of the polynomials which are evaluated at the same point together
-    let mut res = FxHashMap::default();
+    let mut res: FxHashMap<usize, Vec<(&ProverQuery, &Fr)>> =
+        FxHashMap::with_capacity_and_hasher(prover_queries.len(), Default::default());
 
     prover_queries
         .iter()
@@ -81,26 +82,17 @@ impl MultiPoint {
 
         let grouped_queries = group_prover_queries(&queries, &powers_of_r);
 
-        let grouped_queries: Vec<_> = grouped_queries.into_par_iter().collect();
-
-        let chunk_size = grouped_queries.len().div_ceil(rayon::current_num_threads());
-
         // aggregate all of the queries evaluated at the same point
         let aggregated_queries: Vec<_> = grouped_queries
-            .par_chunks(chunk_size)
-            .flat_map(|chunk| {
-                chunk
+            .into_par_iter()
+            .map(|(point, queries_challenges)| {
+                let aggregated_polynomial = queries_challenges
                     .iter()
-                    .map(|(point, queries_challenges)| {
-                        let aggregated_polynomial = queries_challenges
-                            .iter()
-                            .map(|(query, challenge)| query.poly.clone() * *challenge)
-                            .reduce(|acc, x| acc + x)
-                            .expect("Failed to aggregate polynomial");
-
-                        (*point, aggregated_polynomial)
-                    })
-                    .collect::<Vec<_>>()
+                    .map(|(query, challenge)| query.poly.clone() * *challenge)
+                    .reduce(|acc, x| acc + x)
+                    .expect("Failed to aggregate polynomial");
+
+                (point, aggregated_polynomial)
             })
             .collect::<Vec<_>>();