fix/#227 remove unused U1 lookup table (#289)

Fixes last details of #227. Specifically, removes the unused `U1` lookup table which appears to have been added to get `assert_bit` working before `require_zero` was properly functioning. --------- Co-authored-by: Bryan Gillespie <[email protected]> Co-authored-by: naure <[email protected]>
scroll-tech · Sep 27, 2024 · 84098ef · 84098ef
1 parent 2916d6e
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Showing 4 changed files with 7 additions and 13 deletions.
diff --git a/ceno_zkvm/src/chip_handler/general.rs b/ceno_zkvm/src/chip_handler/general.rs
@@ -243,7 +243,6 @@ impl<'a, E: ExtensionField> CircuitBuilder<'a, E> {
         Ok(())
     }
 
-    #[allow(dead_code)]
     pub(crate) fn assert_bit<NR, N>(
         &mut self,
         name_fn: N,
@@ -253,7 +252,13 @@ impl<'a, E: ExtensionField> CircuitBuilder<'a, E> {
         NR: Into<String>,
         N: FnOnce() -> NR,
     {
-        self.require_zero(name_fn, expr.clone() * (Expression::ONE - expr))
+        self.namespace(
+            || "assert_bit",
+            |cb| {
+                cb.cs
+                    .require_zero(name_fn, expr.clone() * (Expression::ONE - expr))
+            },
+        )
     }
 
     /// Assert `rom_type(a, b) = c` and that `a, b, c` are all bytes.

diff --git a/ceno_zkvm/src/structs.rs b/ceno_zkvm/src/structs.rs
@@ -43,7 +43,6 @@ pub type ChallengeId = u16;
 #[derive(Copy, Clone, Debug)]
 pub enum ROMType {
     U5 = 0,      // 2^5 = 32
-    U1,          // TODO: optimize it
     U8,          // 2^8 = 256
     U16,         // 2^16 = 65,536
     And,         // a & b where a, b are bytes

diff --git a/ceno_zkvm/src/tables/range.rs b/ceno_zkvm/src/tables/range.rs
@@ -7,15 +7,6 @@ pub use range_circuit::{RangeTable, RangeTableCircuit};
 
 use crate::structs::ROMType;
 
-pub struct U1Table;
-impl RangeTable for U1Table {
-    const ROM_TYPE: ROMType = ROMType::U1;
-    fn len() -> usize {
-        1 << 1
-    }
-}
-pub type U1TableCircuit<E> = RangeTableCircuit<E, U1Table>;
-
 pub struct U5Table;
 impl RangeTable for U5Table {
     const ROM_TYPE: ROMType = ROMType::U5;

diff --git a/ceno_zkvm/src/witness.rs b/ceno_zkvm/src/witness.rs
@@ -118,7 +118,6 @@ impl LkMultiplicity {
             16 => self.increment(ROMType::U16, v),
             8 => self.increment(ROMType::U8, v),
             5 => self.increment(ROMType::U5, v),
-            1 => self.increment(ROMType::U1, v),
             _ => panic!("Unsupported bit range"),
         }
     }