air: small touchups (#165)

Author: tcoratger

circuit-prover/src/air/const_air.rs

@@ -69,7 +69,7 @@ impl<F: Field, const D: usize> ConstAir<F, D> {
                 "extension degree mismatch for ConstTrace value"
             );
             values.extend_from_slice(coeffs);
-            values.push(F::from_u64(trace.index[i].0 as u64));
+            values.push(F::from_u32(trace.index[i].0));
         }
 
         // Pad to power of two by repeating last row

circuit-prover/src/air/mul_air.rs

@@ -70,9 +70,6 @@ pub struct MulAir<F, const D: usize = 1> {
 }
 
 impl<F: Field + PrimeCharacteristicRing, const D: usize> MulAir<F, D> {
-    /// Number of base-field columns contributed by a single multiplication lane.
-    pub const LANE_WIDTH: usize = 3 * D + 3;
-
     /// Constructor for base-field or non-binomial cases (`D == 1`).
     pub const fn new(num_ops: usize, lanes: usize) -> Self {
         assert!(lanes > 0, "lane count must be non-zero");
@@ -97,8 +94,9 @@ impl<F: Field + PrimeCharacteristicRing, const D: usize> MulAir<F, D> {
         }
     }
 
+    /// Number of base-field columns contributed by a single multiplication lane.
     pub const fn lane_width() -> usize {
-        Self::LANE_WIDTH
+        3 * D + 3
     }
 
     pub fn total_width(&self) -> usize {
@@ -128,13 +126,13 @@ impl<F: Field + PrimeCharacteristicRing, const D: usize> MulAir<F, D> {
                     let lhs_coeffs = trace.lhs_values[op_idx].as_basis_coefficients_slice();
                     assert_eq!(lhs_coeffs.len(), D, "Extension degree mismatch for lhs");
                     values.extend_from_slice(lhs_coeffs);
-                    values.push(F::from_u64(trace.lhs_index[op_idx].0 as u64));
+                    values.push(F::from_u32(trace.lhs_index[op_idx].0));
 
                     // RHS limbs + index
                     let rhs_coeffs = trace.rhs_values[op_idx].as_basis_coefficients_slice();
                     assert_eq!(rhs_coeffs.len(), D, "Extension degree mismatch for rhs");
                     values.extend_from_slice(rhs_coeffs);
-                    values.push(F::from_u64(trace.rhs_index[op_idx].0 as u64));
+                    values.push(F::from_u32(trace.rhs_index[op_idx].0));
 
                     // Result limbs + index
                     let result_coeffs = trace.result_values[op_idx].as_basis_coefficients_slice();
@@ -144,7 +142,7 @@ impl<F: Field + PrimeCharacteristicRing, const D: usize> MulAir<F, D> {
                         "Extension degree mismatch for result",
                     );
                     values.extend_from_slice(result_coeffs);
-                    values.push(F::from_u64(trace.result_index[op_idx].0 as u64));
+                    values.push(F::from_u32(trace.result_index[op_idx].0));
                 } else {
                     // Filler lane: append zeros for unused slot to keep the row width uniform.
                     values.resize(values.len() + lane_width, F::ZERO);

circuit-prover/src/air/public_air.rs

@@ -62,7 +62,7 @@ impl<F: Field, const D: usize> PublicAir<F, D> {
                 "extension degree mismatch for PublicTrace value"
             );
             values.extend_from_slice(coeffs);
-            values.push(F::from_u64(trace.index[i].0 as u64));
+            values.push(F::from_u32(trace.index[i].0));
         }
 
         // Pad to power of two by repeating last row

circuit-prover/src/air/utils.rs

@@ -1,4 +1,5 @@
-/// Shared utilities for AIR implementations
+//! Shared utilities for AIR implementations.
+
 use alloc::vec::Vec;
 
 use p3_field::Field;

circuit-prover/src/air/witness_air.rs

@@ -72,7 +72,7 @@ impl<F: Field, const D: usize> WitnessAir<F, D> {
                 "Extension field degree mismatch for witness value"
             );
             values.extend_from_slice(coeffs);
-            values.push(F::from_u64(trace.index[i].0 as u64));
+            values.push(F::from_u32(trace.index[i].0));
         }
 
         // Pad to power of two with monotonic index continuation
@@ -110,7 +110,7 @@ where
             let nxt = main.row_slice(1).expect("has next row");
             let idx_cur = cur[D].clone();
             let idx_next = nxt[D].clone();
-            b.assert_zero(idx_next - idx_cur - AB::Expr::from(AB::F::ONE));
+            b.assert_zero(idx_next - idx_cur - AB::Expr::ONE);
         }
     }
 }