Cleanup/moving primitive roots to consts

src/consts.rs

@@ -15,3 +15,175 @@ pub enum Endianness {
     Big,
     Little,
 }
+
+pub const PRIMITIVE_ROOTS_OF_UNITY: [[u64; 4]; 29] = [
+    [1, 0, 0, 0],
+    [
+        4891460686036598784,
+        2896914383306846353,
+        13281191951274694749,
+        3486998266802970665,
+    ],
+    [
+        2527087222397613622,
+        6695204439272418284,
+        327476452638867716,
+        3486998266802970665,
+    ],
+    [
+        10704402425919135360,
+        5936434144913852938,
+        17049394741569908534,
+        3112970176132370210,
+    ],
+    [
+        12760115869041182219,
+        11055769604441701272,
+        2048662040769024140,
+        2380201477744082766,
+    ],
+    [
+        4534364320199676624,
+        11247974383505828637,
+        10842451344304943785,
+        704024743550620626,
+    ],
+    [
+        15822547390047388218,
+        5090979784920605886,
+        14000806642677820914,
+        1447929602671906762,
+    ],
+    [
+        11317061033624672273,
+        2146903538426596473,
+        16094987232344622048,
+        1650355948196268433,
+    ],
+    [
+        14453002906517207670,
+        7023718024139043376,
+        17331575720852783024,
+        554159777355432964,
+    ],
+    [
+        9888356262503077838,
+        16730919078578367861,
+        18428778117559158389,
+        1089287402140675931,
+    ],
+    [
+        1295231164603062546,
+        4159771074203146155,
+        16987221740319371747,
+        503587051935343648,
+    ],
+    [
+        14990892138116034274,
+        13312970452735684810,
+        12971070440946883953,
+        178513978866336811,
+    ],
+    [
+        2037726488899540026,
+        8570747871144680377,
+        134492760481370281,
+        662545464149659919,
+    ],
+    [
+        5378594887492817680,
+        15212020320748318070,
+        8420921063925371,
+        31432055529778786,
+    ],
+    [
+        12513816448973172357,
+        13018005335927991014,
+        2255830314307594408,
+        3284907887559304321,
+    ],
+    [
+        12192467936159919355,
+        155983510951534601,
+        103989586739080144,
+        3250374553247014033,
+    ],
+    [
+        15087775233214268343,
+        1641667745675509373,
+        7249316272930938111,
+        67187630906928453,
+    ],
+    [
+        2841305553363228901,
+        365614731812479246,
+        14082910820695433715,
+        2015411323404765442,
+    ],
+    [
+        9567545175896342752,
+        14227021851996246461,
+        6629710949923774029,
+        1863853281588889281,
+    ],
+    [
+        6637559829441244349,
+        3481942500310468410,
+        5873418851262023957,
+        2477233939078171218,
+    ],
+    [
+        5999407858879526999,
+        12421321615888692383,
+        2832916697199010563,
+        2743358069261914211,
+    ],
+    [
+        12882679250960823587,
+        6410035656685935843,
+        4765394507826527372,
+        2156530982351265050,
+    ],
+    [
+        12064543440463545470,
+        17012944649580374971,
+        14817070057475047957,
+        1934629495612430759,
+    ],
+    [
+        13064173989021140381,
+        6233199863045921055,
+        7745012067293438265,
+        148898490380240717,
+    ],
+    [
+        2028293168271393883,
+        1467625613274850966,
+        9596654050255193119,
+        909634523159679186,
+    ],
+    [
+        17063381693978129178,
+        8873981638024286830,
+        11644904980285164756,
+        3058875137825915375,
+    ],
+    [
+        2051879287397454354,
+        6943234193189566894,
+        77669474422529354,
+        1182008650693047218,
+    ],
+    [
+        237279305830403140,
+        13007017166795668898,
+        6856003240715543396,
+        331831521350773736,
+    ],
+    [
+        11229192882073836016,
+        4624371214017703636,
+        63235024940837564,
+        3043318377369730693,
+    ],
+];

src/errors.rs

@@ -14,7 +14,6 @@ pub enum PolynomialError {
     /// Error related to Fast Fourier Transform (FFT) operations with a descriptive message.
     #[error("FFT error: {0}")]
     FFTError(String),
-
     /// A generic error with a descriptive message.
     #[error("generic error: {0}")]
     GenericError(String),

src/helpers.rs

@@ -8,8 +8,8 @@ use std::cmp;
 use crate::{
     arith,
     consts::{
-        Endianness, BYTES_PER_FIELD_ELEMENT, KZG_ENDIANNESS, SIZE_OF_G1_AFFINE_COMPRESSED,
-        SIZE_OF_G2_AFFINE_COMPRESSED,
+        Endianness, BYTES_PER_FIELD_ELEMENT, KZG_ENDIANNESS, PRIMITIVE_ROOTS_OF_UNITY,
+        SIZE_OF_G1_AFFINE_COMPRESSED, SIZE_OF_G2_AFFINE_COMPRESSED,
     },
     errors::KzgError,
     traits::ReadPointFromBytes,
@@ -94,6 +94,10 @@ pub fn remove_empty_byte_from_padded_bytes_unchecked(data: &[u8]) -> Vec<u8> {
     valid_data
 }
 
+pub fn is_zero(fr: Fr) -> bool {
+    fr.0 .0.iter().fold(0, |acc, &x| acc | x) == 0
+}
+
 pub fn set_bytes_canonical(data: &[u8]) -> Fr {
     Fr::from_be_bytes_mod_order(data)
 }
@@ -475,3 +479,40 @@ pub fn g1_lincomb(points: &[G1Affine], scalars: &[Fr]) -> Result<G1Affine, KzgEr
     // This is typically needed as most protocols expect points in affine form
     Ok(lincomb.into_affine())
 }
+
+/// Retrieves and converts a primitive root of unity to a field element
+///
+/// # Arguments
+/// * `index` - Index of the primitive root to retrieve from PRIMITIVE_ROOTS_OF_UNITY array
+///
+/// # Returns
+/// * `Result<Fr, KzgError>` - Field element representation of the primitive root if successful,
+///                           or KzgError if index is invalid or conversion fails
+///
+/// # Errors
+/// - Returns KzgError::GenericError if:
+///   - Index is out of bounds for PRIMITIVE_ROOTS_OF_UNITY array
+///   - BigInt conversion to field element fails
+///
+/// # Details
+/// - Looks up a primitive root of unity from a predefined array using the given index
+/// - Converts the BigInt representation to an Fr field element
+/// - Commonly used in FFT and polynomial operations requiring roots of unity
+///
+/// # Example
+/// ```
+/// use rust_kzg_bn254::helpers::get_and_convert_primitive_root_to_fr;
+/// let root = get_and_convert_primitive_root_to_fr(0); // Gets first primitive root
+/// ```
+pub fn get_and_convert_primitive_root_to_fr(index: usize) -> Result<Fr, KzgError> {
+    let found_root_of_unity_bigint = PRIMITIVE_ROOTS_OF_UNITY
+        .get(index)
+        .ok_or_else(|| KzgError::GenericError("Root of unity not found".to_string()))?;
+
+    let found_root_of_unity = Fr::from_bigint(BigInt::new(*found_root_of_unity_bigint))
+        .ok_or_else(|| {
+            KzgError::GenericError("Failed to convert root of unity from bigint to Fr".to_string())
+        })?;
+
+    Ok(found_root_of_unity)
+}

src/kzg.rs

@@ -16,7 +16,7 @@ use ark_ec::{pairing::Pairing, AffineRepr, CurveGroup, VariableBaseMSM};
 use ark_ff::{BigInteger, Field, PrimeField};
 use ark_poly::{EvaluationDomain, GeneralEvaluationDomain};
 use ark_serialize::{CanonicalSerialize, Read};
-use ark_std::{iterable::Iterable, ops::Div, str::FromStr, One, Zero};
+use ark_std::{iterable::Iterable, ops::Div, One, Zero};
 use crossbeam_channel::{bounded, Sender};
 use num_traits::ToPrimitive;
 use rayon::iter::{IntoParallelRefIterator, ParallelIterator};
@@ -193,16 +193,12 @@ impl KZG {
             ));
         }
 
-        // Get the primitive roots of unity
-        let primitive_roots_of_unity = Self::get_primitive_roots_of_unity()?;
-
         // Find the root of unity corresponding to the calculated log2 value
-        let found_root_of_unity = primitive_roots_of_unity
-            .get(log2_of_evals as usize)
-            .ok_or_else(|| KzgError::GenericError("Root of unity not found".to_string()))?;
+        let found_root_of_unity =
+            helpers::get_and_convert_primitive_root_to_fr(log2_of_evals.into())?;
 
         // Expand the root to get all the roots of unity
-        let mut expanded_roots_of_unity = Self::expand_root_of_unity(found_root_of_unity);
+        let mut expanded_roots_of_unity = Self::expand_root_of_unity(&found_root_of_unity);
 
         // Remove the last element to avoid duplication
         expanded_roots_of_unity.truncate(expanded_roots_of_unity.len() - 1);
@@ -278,13 +274,9 @@ impl KZG {
             ));
         }
 
-        let primitive_roots_of_unity = Self::get_primitive_roots_of_unity()?;
-        let found_root_of_unity = primitive_roots_of_unity
-            .get(log2_of_evals.to_usize().ok_or_else(|| {
-                KzgError::GenericError("Failed to convert log2_of_evals to usize".to_string())
-            })?)
-            .ok_or_else(|| KzgError::GenericError("Root of unity not found".to_string()))?;
-        let mut expanded_roots_of_unity = Self::expand_root_of_unity(found_root_of_unity);
+        let found_root_of_unity =
+            helpers::get_and_convert_primitive_root_to_fr(log2_of_evals.into())?;
+        let mut expanded_roots_of_unity = Self::expand_root_of_unity(&found_root_of_unity);
         expanded_roots_of_unity.truncate(expanded_roots_of_unity.len() - 1);
 
         params.completed_setup = true;
@@ -333,48 +325,6 @@ impl KZG {
         roots
     }
 
-    /// Precompute the primitive roots of unity for binary powers that divide r - 1
-    /// TODO(anupsv): Move this to the constants file. Ref: https://github.com/Layr-Labs/rust-kzg-bn254/issues/31
-    fn get_primitive_roots_of_unity() -> Result<Vec<Fr>, KzgError> {
-        let data: [&str; 29] = [
-            "1",
-            "21888242871839275222246405745257275088548364400416034343698204186575808495616",
-            "21888242871839275217838484774961031246007050428528088939761107053157389710902",
-            "19540430494807482326159819597004422086093766032135589407132600596362845576832",
-            "14940766826517323942636479241147756311199852622225275649687664389641784935947",
-            "4419234939496763621076330863786513495701855246241724391626358375488475697872",
-            "9088801421649573101014283686030284801466796108869023335878462724291607593530",
-            "10359452186428527605436343203440067497552205259388878191021578220384701716497",
-            "3478517300119284901893091970156912948790432420133812234316178878452092729974",
-            "6837567842312086091520287814181175430087169027974246751610506942214842701774",
-            "3161067157621608152362653341354432744960400845131437947728257924963983317266",
-            "1120550406532664055539694724667294622065367841900378087843176726913374367458",
-            "4158865282786404163413953114870269622875596290766033564087307867933865333818",
-            "197302210312744933010843010704445784068657690384188106020011018676818793232",
-            "20619701001583904760601357484951574588621083236087856586626117568842480512645",
-            "20402931748843538985151001264530049874871572933694634836567070693966133783803",
-            "421743594562400382753388642386256516545992082196004333756405989743524594615",
-            "12650941915662020058015862023665998998969191525479888727406889100124684769509",
-            "11699596668367776675346610687704220591435078791727316319397053191800576917728",
-            "15549849457946371566896172786938980432421851627449396898353380550861104573629",
-            "17220337697351015657950521176323262483320249231368149235373741788599650842711",
-            "13536764371732269273912573961853310557438878140379554347802702086337840854307",
-            "12143866164239048021030917283424216263377309185099704096317235600302831912062",
-            "934650972362265999028062457054462628285482693704334323590406443310927365533",
-            "5709868443893258075976348696661355716898495876243883251619397131511003808859",
-            "19200870435978225707111062059747084165650991997241425080699860725083300967194",
-            "7419588552507395652481651088034484897579724952953562618697845598160172257810",
-            "2082940218526944230311718225077035922214683169814847712455127909555749686340",
-            "19103219067921713944291392827692070036145651957329286315305642004821462161904",
-        ];
-        data.iter()
-            .map(Fr::from_str)
-            .collect::<Result<Vec<_>, _>>()
-            .map_err(|_| {
-                KzgError::GenericError("Failed to parse primitive roots of unity".to_string())
-            })
-    }
-
     /// helper function to get g1 points
     pub fn get_g1_points(&self) -> Vec<G1Affine> {
         self.g1.to_vec()