From a053372176cc83c804fa9af6b44cc189808a7ecd Mon Sep 17 00:00:00 2001
From: Nicholas Ward <npward@berkeley.edu>
Date: Mon, 26 Sep 2022 11:19:09 -0700
Subject: [PATCH] cleanup and documentation

---
 field/src/goldilocks_field.rs   | 2 +-
 plonky2/examples/square_root.rs | 5 +++--
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/field/src/goldilocks_field.rs b/field/src/goldilocks_field.rs
index 537b1f11..28d17a05 100644
--- a/field/src/goldilocks_field.rs
+++ b/field/src/goldilocks_field.rs
@@ -303,7 +303,7 @@ impl GoldilocksField {
         } else if self.is_quadratic_residue() {
             let t = (Self::order() - BigUint::from(1u32))
                 / (BigUint::from(2u32).pow(Self::TWO_ADICITY as u32));
-            let mut z = Self::MULTIPLICATIVE_GROUP_GENERATOR.exp_biguint(&t);
+            let mut z = Self::POWER_OF_TWO_GENERATOR;
             let mut w = self.exp_biguint(&((t - BigUint::from(1u32)) / BigUint::from(2u32)));
             let mut x = w * *self;
             let mut b = x * w;
diff --git a/plonky2/examples/square_root.rs b/plonky2/examples/square_root.rs
index b20bf8e6..230b33aa 100644
--- a/plonky2/examples/square_root.rs
+++ b/plonky2/examples/square_root.rs
@@ -19,6 +19,8 @@ struct SquareRootGenerator<F: RichField + Extendable<D>, const D: usize> {
     _phantom: PhantomData<F>,
 }
 
+// We implement specifically for the Goldilocks field because it's currently the only field with
+// the sqrt() function written.
 impl SimpleGenerator<GoldilocksField> for SquareRootGenerator<GoldilocksField, 2> {
     fn dependencies(&self) -> Vec<Target> {
         vec![self.x_squared]
@@ -30,15 +32,14 @@ impl SimpleGenerator<GoldilocksField> for SquareRootGenerator<GoldilocksField, 2
         out_buffer: &mut GeneratedValues<GoldilocksField>,
     ) {
         let x_squared = witness.get_target(self.x_squared);
-        dbg!(x_squared);
         let x = x_squared.sqrt().unwrap();
-        dbg!(x);
 
         out_buffer.set_target(self.x, x);
     }
 }
 
 /// An example of using Plonky2 to prove a statement of the form
+/// "I know the square root of this field element."
 fn main() -> Result<()> {
     const D: usize = 2;
     type C = PoseidonGoldilocksConfig;