Remove Plonkup3Arity (#619)

* Remove `PlonkupTable3Arity`
* Change to use `PlonkupTable4Arity`
* Rename `PlonkupTable4Arity` to `IndexTable`
* Fix tests to work with `IndexTable`
* Remove bigint crate and the usage of `u256` from plonkup

See also: #589 

Co-authored-by: zer0 <matteo@dusk.network>

Cargo.toml

@@ -14,7 +14,6 @@ description = "A pure-Rust implementation of the PLONK ZK-Proof algorithm"
 exclude = [ ".github/" ]
 
 [dependencies]
-bigint = "4.4"
 merlin = {version = "3.0", default-features = false}
 rand_core = {version="0.6", default-features=false}
 dusk-bytes = "0.1"

src/constraint_system/composer.rs

@@ -20,7 +20,7 @@
 
 use crate::constraint_system::{Constraint, Selector, Witness};
 use crate::permutation::Permutation;
-use crate::plonkup::PlonkupTable4Arity;
+use crate::plonkup::LookupTable;
 use alloc::collections::BTreeMap;
 use alloc::vec::Vec;
 use dusk_bls12_381::BlsScalar;
@@ -96,7 +96,7 @@ pub struct TurboComposer {
     pub(crate) w_4: Vec<Witness>,
 
     /// Public lookup table
-    pub(crate) lookup_table: PlonkupTable4Arity,
+    pub(crate) lookup_table: LookupTable,
 
     /// A zero Witness that is a part of the circuit description.
     /// We reserve a variable to be zero in the system
@@ -218,7 +218,7 @@ impl TurboComposer {
             w_o: Vec::with_capacity(size),
             w_4: Vec::with_capacity(size),
 
-            lookup_table: PlonkupTable4Arity::new(),
+            lookup_table: LookupTable::new(),
 
             constant_zero: Witness::new(0),
 
@@ -760,7 +760,7 @@ impl TurboComposer {
     /// When [`TurboComposer`] is initialised, it spawns a dummy table
     /// with 3 entries that should not be removed. This function appends
     /// its input table to the composer's dummy table
-    pub fn append_plonkup_table(&mut self, table: &PlonkupTable4Arity) {
+    pub fn append_plonkup_table(&mut self, table: &LookupTable) {
         table.0.iter().for_each(|k| self.lookup_table.0.push(*k))
     }
 }
@@ -828,7 +828,7 @@ mod tests {
 
     #[test]
     fn test_gadget() {
-        let mut t = PlonkupTable4Arity::new();
+        let mut t = LookupTable::new();
         t.insert_special_row(
             BlsScalar::from(12),
             BlsScalar::from(12),
@@ -872,7 +872,7 @@ mod tests {
     #[test]
     #[should_panic]
     fn test_gadget_fail() {
-        let mut t = PlonkupTable4Arity::new();
+        let mut t = LookupTable::new();
         t.insert_special_row(
             BlsScalar::from(12),
             BlsScalar::from(12),

src/constraint_system/helper.rs

@@ -8,7 +8,7 @@ use super::TurboComposer;
 use crate::commitment_scheme::PublicParameters;
 use crate::constraint_system::Constraint;
 use crate::error::Error;
-use crate::plonkup::PlonkupTable4Arity;
+use crate::plonkup::LookupTable;
 use crate::proof_system::{Prover, Verifier};
 use dusk_bls12_381::BlsScalar;
 use rand_core::OsRng;
@@ -100,7 +100,7 @@ pub(crate) fn gadget_tester(
 pub(crate) fn gadget_plonkup_tester(
     gadget: fn(composer: &mut TurboComposer),
     n: usize,
-    lookup_table: PlonkupTable4Arity,
+    lookup_table: LookupTable,
 ) -> Result<(), Error> {
     // Common View
     let public_parameters = PublicParameters::setup(2 * n, &mut OsRng)?;

src/plonkup.rs

@@ -17,7 +17,6 @@ pub(crate) mod table;
 pub use multiset::MultiSet;
 pub use table::hash_tables::constants;
 pub use table::{
-    lookup_table::{PlonkupTable3Arity, PlonkupTable4Arity},
-    preprocess::{PreprocessedTable3Arity, PreprocessedTable4Arity},
-    witness_table::{WitnessTable3Arity, WitnessTable4Arity},
+    lookup_table::LookupTable, preprocess::PreprocessedLookupTable,
+    witness_table::WitnessTable,
 };

src/plonkup/multiset.rs

@@ -242,7 +242,7 @@ impl Mul for MultiSet {
 mod test {
     use super::*;
     use crate::fft::EvaluationDomain;
-    use crate::plonkup::WitnessTable3Arity;
+    use crate::plonkup::WitnessTable;
 
     #[test]
     fn test_halve() {
@@ -384,7 +384,7 @@ mod test {
         let alpha = BlsScalar::from(2);
         let alpha_squared = alpha * alpha;
 
-        let mut table = WitnessTable3Arity::default();
+        let mut table = WitnessTable::default();
 
         // Fill in wires directly, no need to use a
         // plonkup table as this will not be going
@@ -393,6 +393,7 @@ mod test {
             BlsScalar::from(1),
             BlsScalar::from(2),
             BlsScalar::from(3),
+            BlsScalar::from(4),
         );
 
         // Computed expected result

src/plonkup/table/hash_tables.rs

@@ -10,6 +10,4 @@
 /// Module containing constants required in reinforced concrete
 pub mod constants;
 
-pub use constants::{
-    BLS_SCALAR_REAL, DECOMPOSITION_S_I, N, S, SBOX_U256, T_S, V,
-};
+pub use constants::{BLS_SCALAR_REAL, DECOMPOSITION_S_I, N, S, SBOX, T_S, V};