Add fixed columns to uni-stark

air/src/air.rs

@@ -12,6 +12,11 @@ pub trait BaseAir<F>: Sync {
     fn preprocessed_trace(&self) -> Option<RowMajorMatrix<F>> {
         None
     }
+
+    /// The number of preprocessed columns in this AIR
+    fn preprocessed_width(&self) -> usize {
+        0
+    }
 }
 
 /// An AIR that works with a particular `AirBuilder`.

uni-stark/src/check_constraints.rs

@@ -1,15 +1,19 @@
 use alloc::vec::Vec;
 
-use p3_air::{Air, AirBuilder, AirBuilderWithPublicValues};
+use p3_air::{Air, AirBuilder, AirBuilderWithPublicValues, PairBuilder};
 use p3_field::Field;
 use p3_matrix::dense::{RowMajorMatrix, RowMajorMatrixView};
 use p3_matrix::stack::VerticalPair;
 use p3_matrix::Matrix;
 use tracing::instrument;
 
 #[instrument(name = "check constraints", skip_all)]
-pub(crate) fn check_constraints<F, A>(air: &A, main: &RowMajorMatrix<F>, public_values: &Vec<F>)
-where
+pub(crate) fn check_constraints<F, A>(
+    air: &A,
+    preprocessed: &RowMajorMatrix<F>,
+    main: &RowMajorMatrix<F>,
+    public_values: &Vec<F>,
+) where
     F: Field,
     A: for<'a> Air<DebugConstraintBuilder<'a, F>>,
 {
@@ -18,6 +22,13 @@ where
     (0..height).for_each(|i| {
         let i_next = (i + 1) % height;
 
+        let local_preprocessed = preprocessed.row_slice(i);
+        let next_preprocessed = preprocessed.row_slice(i_next);
+        let preprocessed = VerticalPair::new(
+            RowMajorMatrixView::new_row(&*local_preprocessed),
+            RowMajorMatrixView::new_row(&*next_preprocessed),
+        );
+
         let local = main.row_slice(i);
         let next = main.row_slice(i_next);
         let main = VerticalPair::new(
@@ -27,6 +38,7 @@ where
 
         let mut builder = DebugConstraintBuilder {
             row_index: i,
+            preprocessed,
             main,
             public_values,
             is_first_row: F::from_bool(i == 0),
@@ -43,6 +55,7 @@ where
 #[derive(Debug)]
 pub struct DebugConstraintBuilder<'a, F: Field> {
     row_index: usize,
+    preprocessed: VerticalPair<RowMajorMatrixView<'a, F>, RowMajorMatrixView<'a, F>>,
     main: VerticalPair<RowMajorMatrixView<'a, F>, RowMajorMatrixView<'a, F>>,
     public_values: &'a [F],
     is_first_row: F,
@@ -106,3 +119,9 @@ impl<'a, F: Field> AirBuilderWithPublicValues for DebugConstraintBuilder<'a, F>
         self.public_values
     }
 }
+
+impl<'a, F: Field> PairBuilder for DebugConstraintBuilder<'a, F> {
+    fn preprocessed(&self) -> Self::M {
+        self.preprocessed
+    }
+}

uni-stark/src/folder.rs

@@ -1,6 +1,6 @@
 use alloc::vec::Vec;
 
-use p3_air::{AirBuilder, AirBuilderWithPublicValues};
+use p3_air::{AirBuilder, AirBuilderWithPublicValues, PairBuilder};
 use p3_field::AbstractField;
 use p3_matrix::dense::{RowMajorMatrix, RowMajorMatrixView};
 use p3_matrix::stack::VerticalPair;
@@ -10,6 +10,7 @@ use crate::{PackedChallenge, PackedVal, StarkGenericConfig, Val};
 #[derive(Debug)]
 pub struct ProverConstraintFolder<'a, SC: StarkGenericConfig> {
     pub main: RowMajorMatrix<PackedVal<SC>>,
+    pub preprocessed: RowMajorMatrix<PackedVal<SC>>,
     pub public_values: &'a Vec<Val<SC>>,
     pub is_first_row: PackedVal<SC>,
     pub is_last_row: PackedVal<SC>,
@@ -23,6 +24,7 @@ type ViewPair<'a, T> = VerticalPair<RowMajorMatrixView<'a, T>, RowMajorMatrixVie
 #[derive(Debug)]
 pub struct VerifierConstraintFolder<'a, SC: StarkGenericConfig> {
     pub main: ViewPair<'a, SC::Challenge>,
+    pub preprocessed: ViewPair<'a, SC::Challenge>,
     pub public_values: &'a Vec<Val<SC>>,
     pub is_first_row: SC::Challenge,
     pub is_last_row: SC::Challenge,
@@ -72,6 +74,12 @@ impl<'a, SC: StarkGenericConfig> AirBuilderWithPublicValues for ProverConstraint
     }
 }
 
+impl<'a, SC: StarkGenericConfig> PairBuilder for ProverConstraintFolder<'a, SC> {
+    fn preprocessed(&self) -> Self::M {
+        self.preprocessed.clone()
+    }
+}
+
 impl<'a, SC: StarkGenericConfig> AirBuilder for VerifierConstraintFolder<'a, SC> {
     type F = Val<SC>;
     type Expr = SC::Challenge;
@@ -112,3 +120,9 @@ impl<'a, SC: StarkGenericConfig> AirBuilderWithPublicValues for VerifierConstrai
         self.public_values
     }
 }
+
+impl<'a, SC: StarkGenericConfig> PairBuilder for VerifierConstraintFolder<'a, SC> {
+    fn preprocessed(&self) -> Self::M {
+        self.preprocessed
+    }
+}

uni-stark/src/proof.rs

@@ -13,6 +13,10 @@ type PcsProof<SC> = <<SC as StarkGenericConfig>::Pcs as Pcs<
     <SC as StarkGenericConfig>::Challenge,
     <SC as StarkGenericConfig>::Challenger,
 >>::Proof;
+pub type PcsProverData<SC> = <<SC as StarkGenericConfig>::Pcs as Pcs<
+    <SC as StarkGenericConfig>::Challenge,
+    <SC as StarkGenericConfig>::Challenger,
+>>::ProverData;
 
 #[derive(Serialize, Deserialize)]
 #[serde(bound = "")]
@@ -31,7 +35,20 @@ pub struct Commitments<Com> {
 
 #[derive(Debug, Serialize, Deserialize)]
 pub struct OpenedValues<Challenge> {
+    pub(crate) preprocessed_local: Vec<Challenge>,
+    pub(crate) preprocessed_next: Vec<Challenge>,
     pub(crate) trace_local: Vec<Challenge>,
     pub(crate) trace_next: Vec<Challenge>,
     pub(crate) quotient_chunks: Vec<Vec<Challenge>>,
 }
+
+pub struct StarkProvingKey<SC: StarkGenericConfig> {
+    pub preprocessed_commit: Com<SC>,
+    pub preprocessed_data: PcsProverData<SC>,
+}
+
+#[derive(Serialize, Deserialize)]
+#[serde(bound = "")]
+pub struct StarkVerifyingKey<SC: StarkGenericConfig> {
+    pub preprocessed_commit: Com<SC>,
+}

uni-stark/src/prover.rs

@@ -16,7 +16,7 @@ use tracing::{info_span, instrument};
 use crate::symbolic_builder::{get_log_quotient_degree, SymbolicAirBuilder};
 use crate::{
     Commitments, Domain, OpenedValues, PackedChallenge, PackedVal, Proof, ProverConstraintFolder,
-    StarkGenericConfig, Val,
+    StarkGenericConfig, StarkProvingKey, Val,
 };
 
 #[instrument(skip_all)]
@@ -32,17 +32,44 @@ pub fn prove<
     trace: RowMajorMatrix<Val<SC>>,
     public_values: &Vec<Val<SC>>,
 ) -> Proof<SC>
+where
+    SC: StarkGenericConfig,
+    A: Air<SymbolicAirBuilder<Val<SC>>> + for<'a> Air<ProverConstraintFolder<'a, SC>>,
+{
+    prove_with_key(config, None, air, challenger, trace, public_values)
+}
+
+#[instrument(skip_all)]
+#[allow(clippy::multiple_bound_locations)] // cfg not supported in where clauses?
+pub fn prove_with_key<
+    SC,
+    #[cfg(debug_assertions)] A: for<'a> Air<crate::check_constraints::DebugConstraintBuilder<'a, Val<SC>>>,
+    #[cfg(not(debug_assertions))] A,
+>(
+    config: &SC,
+    proving_key: Option<&StarkProvingKey<SC>>,
+    air: &A,
+    challenger: &mut SC::Challenger,
+    trace: RowMajorMatrix<Val<SC>>,
+    public_values: &Vec<Val<SC>>,
+) -> Proof<SC>
 where
     SC: StarkGenericConfig,
     A: Air<SymbolicAirBuilder<Val<SC>>> + for<'a> Air<ProverConstraintFolder<'a, SC>>,
 {
     #[cfg(debug_assertions)]
-    crate::check_constraints::check_constraints(air, &trace, public_values);
+    crate::check_constraints::check_constraints(
+        air,
+        &air.preprocessed_trace()
+            .unwrap_or(RowMajorMatrix::new(vec![], 0)),
+        &trace,
+        public_values,
+    );
 
     let degree = trace.height();
     let log_degree = log2_strict_usize(degree);
 
-    let log_quotient_degree = get_log_quotient_degree::<Val<SC>, A>(air, 0, public_values.len());
+    let log_quotient_degree = get_log_quotient_degree::<Val<SC>, A>(air, public_values.len());
     let quotient_degree = 1 << log_quotient_degree;
 
     let pcs = config.pcs();
@@ -55,20 +82,28 @@ where
     challenger.observe(Val::<SC>::from_canonical_usize(log_degree));
     // TODO: Might be best practice to include other instance data here; see verifier comment.
 
+    if let Some(proving_key) = proving_key {
+        challenger.observe(proving_key.preprocessed_commit.clone())
+    };
     challenger.observe(trace_commit.clone());
     challenger.observe_slice(public_values);
     let alpha: SC::Challenge = challenger.sample_ext_element();
 
     let quotient_domain =
         trace_domain.create_disjoint_domain(1 << (log_degree + log_quotient_degree));
 
+    let preprocessed_on_quotient_domain = proving_key.map(|proving_key| {
+        pcs.get_evaluations_on_domain(&proving_key.preprocessed_data, 0, quotient_domain)
+    });
+
     let trace_on_quotient_domain = pcs.get_evaluations_on_domain(&trace_data, 0, quotient_domain);
 
     let quotient_values = quotient_values(
         air,
         public_values,
         trace_domain,
         quotient_domain,
+        preprocessed_on_quotient_domain,
         trace_on_quotient_domain,
         alpha,
     );
@@ -89,22 +124,54 @@ where
     let zeta_next = trace_domain.next_point(zeta).unwrap();
 
     let (opened_values, opening_proof) = pcs.open(
-        vec![
-            (&trace_data, vec![vec![zeta, zeta_next]]),
-            (
-                &quotient_data,
-                // open every chunk at zeta
-                (0..quotient_degree).map(|_| vec![zeta]).collect_vec(),
-            ),
-        ],
+        iter::empty()
+            .chain(
+                proving_key
+                    .map(|proving_key| {
+                        (&proving_key.preprocessed_data, vec![vec![zeta, zeta_next]])
+                    })
+                    .into_iter(),
+            )
+            .chain([
+                (&trace_data, vec![vec![zeta, zeta_next]]),
+                (
+                    &quotient_data,
+                    // open every chunk at zeta
+                    (0..quotient_degree).map(|_| vec![zeta]).collect_vec(),
+                ),
+            ])
+            .collect_vec(),
         challenger,
     );
-    let trace_local = opened_values[0][0][0].clone();
-    let trace_next = opened_values[0][0][1].clone();
-    let quotient_chunks = opened_values[1].iter().map(|v| v[0].clone()).collect_vec();
+    let mut opened_values = opened_values.iter();
+
+    // maybe get values for the preprocessed columns
+    let (preprocessed_local, preprocessed_next) = if proving_key.is_some() {
+        let value = opened_values.next().unwrap();
+        assert_eq!(value.len(), 1);
+        assert_eq!(value[0].len(), 2);
+        (value[0][0].clone(), value[0][1].clone())
+    } else {
+        (vec![], vec![])
+    };
+
+    // get values for the trace
+    let value = opened_values.next().unwrap();
+    assert_eq!(value.len(), 1);
+    assert_eq!(value[0].len(), 2);
+    let trace_local = value[0][0].clone();
+    let trace_next = value[0][1].clone();
+
+    // get values for the quotient
+    let value = opened_values.next().unwrap();
+    assert_eq!(value.len(), quotient_degree);
+    let quotient_chunks = value.iter().map(|v| v[0].clone()).collect_vec();
+
     let opened_values = OpenedValues {
         trace_local,
         trace_next,
+        preprocessed_local,
+        preprocessed_next,
         quotient_chunks,
     };
     Proof {
@@ -121,6 +188,7 @@ fn quotient_values<SC, A, Mat>(
     public_values: &Vec<Val<SC>>,
     trace_domain: Domain<SC>,
     quotient_domain: Domain<SC>,
+    preprocessed_on_quotient_domain: Option<Mat>,
     trace_on_quotient_domain: Mat,
     alpha: SC::Challenge,
 ) -> Vec<SC::Challenge>
@@ -130,6 +198,10 @@ where
     Mat: Matrix<Val<SC>> + Sync,
 {
     let quotient_size = quotient_domain.size();
+    let preprocessed_width = preprocessed_on_quotient_domain
+        .as_ref()
+        .map(Matrix::width)
+        .unwrap_or_default();
     let width = trace_on_quotient_domain.width();
     let mut sels = trace_domain.selectors_on_coset(quotient_domain);
 
@@ -156,6 +228,19 @@ where
             let is_transition = *PackedVal::<SC>::from_slice(&sels.is_transition[i_range.clone()]);
             let inv_zeroifier = *PackedVal::<SC>::from_slice(&sels.inv_zeroifier[i_range.clone()]);
 
+            let preprocessed = RowMajorMatrix::new(
+                preprocessed_on_quotient_domain
+                    .as_ref()
+                    .map(|on_quotient_domain| {
+                        iter::empty()
+                            .chain(on_quotient_domain.vertically_packed_row(i_start))
+                            .chain(on_quotient_domain.vertically_packed_row(i_start + next_step))
+                            .collect_vec()
+                    })
+                    .unwrap_or_default(),
+                preprocessed_width,
+            );
+
             let main = RowMajorMatrix::new(
                 iter::empty()
                     .chain(trace_on_quotient_domain.vertically_packed_row(i_start))
@@ -166,6 +251,7 @@ where
 
             let accumulator = PackedChallenge::<SC>::zero();
             let mut folder = ProverConstraintFolder {
+                preprocessed,
                 main,
                 public_values,
                 is_first_row,