Fix non-parallel bugs.

Author: leo-starkware

crates/stwo/src/prover/backend/simd/grind.rs

@@ -146,7 +146,7 @@ pub mod poseidon252 {
             ]);
             #[cfg(not(feature = "parallel"))]
             let res = (0..)
-                .find_map(|hi| grind_poseidon(digest, hi, pow_bits))
+                .find_map(|hi| grind_poseidon(prefixed_digest, hi, pow_bits))
                 .expect("Grind failed to find a solution.");
 
             #[cfg(feature = "parallel")]

crates/stwo/src/prover/backend/simd/poseidon252_lifted.rs

@@ -9,7 +9,6 @@ use crate::core::vcs_lifted::merkle_hasher::MerkleHasherLifted;
 use crate::core::vcs_lifted::poseidon252_merkle::{
     poseidon_finalize, poseidon_update, Poseidon252MerkleHasher, ELEMENTS_IN_BUFFER,
 };
-#[cfg(feature = "parallel")]
 use crate::prover::backend::simd::m31::N_LANES;
 use crate::prover::backend::simd::SimdBackend;
 use crate::prover::backend::{Col, Column, CpuBackend};

crates/stwo/src/prover/backend/simd/quotients.rs

@@ -93,10 +93,10 @@ impl QuotientOps for SimdBackend {
         // Populate `quotients`.
         // TODO(Leo): make chunk size configurable.
         #[cfg(not(feature = "parallel"))]
-        let iter = quotients.iter_mut(1).enumerate();
+        let iter = quotients.chunks_mut(1).enumerate();
 
         #[cfg(feature = "parallel")]
-        let iter = quotients.chunks_mut(1).enumerate();
+        let iter = quotients.par_chunks_mut(1).enumerate();
 
         iter.for_each(|(domain_idx, mut value_dst)| {
             let mut quotient = PackedSecureField::zero();
@@ -147,7 +147,7 @@ fn denominator_inverses(
     let domain_points = CircleDomainBitRevIterator::new(domain);
 
     #[cfg(not(feature = "parallel"))]
-    let iter = domain_points.iter();
+    let iter = domain_points;
 
     #[cfg(feature = "parallel")]
     let iter = domain_points.par_iter();