From 3fd52581912991e16c53c7f035fe3874269bdff8 Mon Sep 17 00:00:00 2001
From: wborgeaud <williamborgeaud@gmail.com>
Date: Tue, 15 Feb 2022 18:00:53 +0100
Subject: [PATCH] Comments

---
 plonky2/src/gates/gate.rs            | 4 +++-
 plonky2/src/iop/generator.rs         | 5 -----
 plonky2/src/plonk/circuit_builder.rs | 7 ++++++-
 3 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/plonky2/src/gates/gate.rs b/plonky2/src/gates/gate.rs
index 1d6a0e3d..c84c6595 100644
--- a/plonky2/src/gates/gate.rs
+++ b/plonky2/src/gates/gate.rs
@@ -143,7 +143,8 @@ pub trait Gate<F: RichField + Extendable<D>, const D: usize>: 'static + Send + S
 
     /// Number of operations performed by the gate.
     fn num_ops(&self) -> usize {
-        self.generators(0, &[F::ZERO; 100]).len()
+        self.generators(0, &vec![F::ZERO; self.num_constants()])
+            .len()
     }
 }
 
@@ -177,6 +178,7 @@ impl<F: RichField + Extendable<D>, const D: usize> Debug for GateRef<F, D> {
     }
 }
 
+/// Map between gate parameters and available slots.
 #[derive(Clone, Debug)]
 pub struct CurrentSlot<F: RichField + Extendable<D>, const D: usize> {
     pub current_slot: HashMap<Vec<F>, (usize, usize)>,
diff --git a/plonky2/src/iop/generator.rs b/plonky2/src/iop/generator.rs
index 0105e031..1569e889 100644
--- a/plonky2/src/iop/generator.rs
+++ b/plonky2/src/iop/generator.rs
@@ -91,11 +91,6 @@ pub(crate) fn generate_partial_witness<
         pending_generator_indices = next_pending_generator_indices;
     }
 
-    for i in 0..generator_is_expired.len() {
-        if !generator_is_expired[i] {
-            dbg!(i);
-        }
-    }
     assert_eq!(
         remaining_generators, 0,
         "{} generators weren't run",
diff --git a/plonky2/src/plonk/circuit_builder.rs b/plonky2/src/plonk/circuit_builder.rs
index aa4c67be..5c5f66f0 100644
--- a/plonky2/src/plonk/circuit_builder.rs
+++ b/plonky2/src/plonk/circuit_builder.rs
@@ -81,6 +81,7 @@ pub struct CircuitBuilder<F: RichField + Extendable<D>, const D: usize> {
     /// Memoized results of `arithmetic_extension` calls.
     pub(crate) arithmetic_results: HashMap<ExtensionArithmeticOperation<F, D>, ExtensionTarget<D>>,
 
+    /// Map between gate type and the current gate of this type with available slots.
     current_slots: HashMap<GateRef<F, D>, CurrentSlot<F, D>>,
 }
 
@@ -211,7 +212,6 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
         constants: Vec<F>,
         params: Vec<F>,
     ) -> usize {
-        // println!("{} {}", self.num_gates(), gate_type.id());
         self.check_gate_compatibility(&gate_type);
         assert_eq!(
             gate_type.num_constants(),
@@ -397,6 +397,7 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
         })
     }
 
+    /// Find an available slot, of the form `(gate_index, op)` for gate `G`.
     pub fn find_slot<G: Gate<F, D> + Clone>(
         &mut self,
         gate: G,
@@ -420,12 +421,14 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
             (num_gates, 0)
         };
         if res.1 == num_ops - 1 {
+            // We've filled up the slots at this index.
             self.current_slots
                 .get_mut(&gate_ref)
                 .unwrap()
                 .current_slot
                 .remove(params);
         } else {
+            // Increment the slot operation index.
             self.current_slots
                 .get_mut(&gate_ref)
                 .unwrap()
@@ -737,6 +740,7 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
             constants_sigmas_cap: constants_sigmas_cap.clone(),
         };
 
+        // Map between gates where not all generators are used and the gate's number of used generators.
         let incomplete_gates = self
             .current_slots
             .values()
@@ -750,6 +754,7 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
                 .enumerate()
                 .flat_map(|(index, gate)| {
                     let mut gens = gate.gate_ref.0.generators(index, &gate.constants);
+                    // Remove unused generators, if any.
                     if let Some(&op) = incomplete_gates.get(&index) {
                         gens.drain(op..);
                     }