fix the lookup alpha bug

crates/prover/src/constraint_framework/logup.rs

@@ -119,7 +119,7 @@ pub struct LookupElements<const N: usize> {
 impl<const N: usize> LookupElements<N> {
     pub fn draw(channel: &mut impl Channel) -> Self {
         let [z, alpha] = channel.draw_felts(2).try_into().unwrap();
-        let mut cur = SecureField::one();
+        let mut cur = alpha;
         let alpha_powers = std::array::from_fn(|_| {
             let res = cur;
             cur *= alpha;