From a760e436ed2ee92d29969dae2349d142e23f6533 Mon Sep 17 00:00:00 2001
From: danielsanchezq <sanchez.quiros.daniel@gmail.com>
Date: Fri, 14 Jun 2024 15:04:09 +0200
Subject: [PATCH] Fix parallel feature tagging

---
 nomos-da/kzgrs/benches/kzg.rs |  4 ++++
 nomos-da/kzgrs/src/fft.rs     | 20 ++++++++++----------
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/nomos-da/kzgrs/benches/kzg.rs b/nomos-da/kzgrs/benches/kzg.rs
index 18c26eb6..e7cbbcee 100644
--- a/nomos-da/kzgrs/benches/kzg.rs
+++ b/nomos-da/kzgrs/benches/kzg.rs
@@ -6,7 +6,9 @@ use divan::counter::ItemsCount;
 use divan::{black_box, counter::BytesCount, AllocProfiler, Bencher};
 use once_cell::sync::Lazy;
 use rand::RngCore;
+#[cfg(feature = "parallel")]
 use rayon::iter::IntoParallelIterator;
+#[cfg(feature = "parallel")]
 use rayon::iter::ParallelIterator;
 
 use kzgrs::{common::bytes_to_polynomial_unchecked, kzg::*};
@@ -46,6 +48,7 @@ fn commit_single_polynomial_with_element_count(bencher: Bencher, element_count:
         .bench_refs(|(_evals, poly)| black_box(commit_polynomial(poly, &GLOBAL_PARAMETERS)));
 }
 
+#[cfg(feature = "parallel")]
 #[allow(non_snake_case)]
 #[divan::bench(args = [16, 32, 64, 128, 256, 512, 1024, 2048, 4096])]
 fn commit_polynomial_with_element_count_parallelized(bencher: Bencher, element_count: usize) {
@@ -114,6 +117,7 @@ fn compute_batch_proofs(bencher: Bencher, element_count: usize) {
 // This is a test on how will perform by having a wrapping rayon on top of the proof computation
 // ark libraries already use rayon underneath so no great improvements are probably come up from this.
 // But it should help reusing the same thread pool for all jobs saving a little time.
+#[cfg(feature = "parallel")]
 #[allow(non_snake_case)]
 #[divan::bench(args = [128, 256, 512, 1024], sample_count = 3, sample_size = 5)]
 fn compute_parallelize_batch_proofs(bencher: Bencher, element_count: usize) {
diff --git a/nomos-da/kzgrs/src/fft.rs b/nomos-da/kzgrs/src/fft.rs
index 84a410ac..66edf55b 100644
--- a/nomos-da/kzgrs/src/fft.rs
+++ b/nomos-da/kzgrs/src/fft.rs
@@ -2,7 +2,7 @@ use ark_bls12_381::{Bls12_381, Fr, G1Affine};
 use ark_ec::pairing::Pairing;
 use ark_ec::{AffineRepr, CurveGroup};
 use ark_ff::{BigInt, BigInteger, FftField, Field, PrimeField};
-#[cfg(parallel)]
+#[cfg(feature = "parallel")]
 use rayon::iter::IntoParallelIterator;
 
 pub fn fft_g1(vals: &[G1Affine], roots_of_unity: &[Fr]) -> Vec<G1Affine> {
@@ -36,22 +36,22 @@ pub fn fft_g1(vals: &[G1Affine], roots_of_unity: &[Fr]) -> Vec<G1Affine> {
     };
 
     let [l, r]: [Vec<G1Affine>; 2] = {
-        #[cfg(parallel)]
+        #[cfg(feature = "parallel")]
         {
             [l, r].into_par_iter().map(|f| f()).collect()
         }
-        #[cfg(not(parallel))]
+        #[cfg(not(feature = "parallel"))]
         {
             [l(), r()]
         }
     };
 
     let y_times_root = {
-        #[cfg(parallel)]
+        #[cfg(feature = "parallel")]
         {
             r.into_par_iter()
         }
-        #[cfg(not(parallel))]
+        #[cfg(not(feature = "parallel"))]
         {
             r.into_iter()
         }
@@ -61,11 +61,11 @@ pub fn fft_g1(vals: &[G1Affine], roots_of_unity: &[Fr]) -> Vec<G1Affine> {
     .map(|(i, y)| (y * roots_of_unity[i % vals.len()]).into_affine());
 
     {
-        #[cfg(parallel)]
+        #[cfg(feature = "parallel")]
         {
             l.into_par_iter()
         }
-        #[cfg(not(parallel))]
+        #[cfg(not(feature = "parallel"))]
         {
             l.into_iter()
         }
@@ -90,11 +90,11 @@ pub fn ifft_g1(vals: &[G1Affine], roots_of_unity: &[Fr]) -> Vec<G1Affine> {
     let mut mod_min_2 = BigInt::new(<Fr as PrimeField>::MODULUS.0);
     mod_min_2.sub_with_borrow(&BigInt::<4>::from(2u64));
     let invlen = Fr::from(vals.len() as u64).pow(mod_min_2).into_bigint();
-    #[cfg(parallel)]
+    #[cfg(feature = "parallel")]
     {
-        fft_g1(vals, roots_of_unity).into_par_iter()
+        fft_g1(vals, roots_of_unity).into_par_iter().collect()
     }
-    #[cfg(not(parallel))]
+    #[cfg(not(feature = "parallel"))]
     { fft_g1(vals, roots_of_unity).into_iter() }
         .map(|g| g.mul_bigint(invlen).into_affine())
         .collect()