From 39b22a6cab780adf2e99c14218584ae3b4c8defe Mon Sep 17 00:00:00 2001
From: Nicholas Ward <npward@berkeley.edu>
Date: Thu, 1 Jul 2021 12:00:56 -0700
Subject: [PATCH] addressed nits

---
 src/gadgets/insert.rs | 5 ++++-
 src/generator.rs      | 4 +---
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/gadgets/insert.rs b/src/gadgets/insert.rs
index 64260209..7a1ee98d 100644
--- a/src/gadgets/insert.rs
+++ b/src/gadgets/insert.rs
@@ -6,11 +6,14 @@ use crate::target::Target;
 
 impl<F: Extendable<D>, const D: usize> CircuitBuilder<F, D> {
     /// Evaluates to 0 if `x` equals zero, 1 otherwise.
+    /// From section 2 of https://github.com/mir-protocol/r1cs-workshop/blob/master/workshop.pdf,
+    /// based on an idea from https://eprint.iacr.org/2012/598.pdf.
     pub fn is_nonzero(&mut self, x: Target) -> Target {
         // Dummy variable.
         let m = self.add_virtual_target();
 
-        // The prover sets the dummy variable to 0 if x == 0 and to 1/x otherwise.
+        // The prover sets this the dummy variable to 1/x if x != 0, or to an arbitrary value if
+        // x == 0.
         self.add_generator(NonzeroTestGenerator {
             to_test: x,
             dummy: m,
diff --git a/src/generator.rs b/src/generator.rs
index 3795fdfa..a47c5267 100644
--- a/src/generator.rs
+++ b/src/generator.rs
@@ -151,8 +151,6 @@ impl<F: Field> SimpleGenerator<F> for NonzeroTestGenerator {
             to_test_value.inverse()
         };
 
-        let mut witness = PartialWitness::new();
-        witness.set_target(self.dummy, dummy_value);
-        witness
+        PartialWitness::singleton_target(self.dummy, dummy_value)
     }
 }