From 1ceb60379fa4ab62c961dfe8f44ff5b3d2c6cc51 Mon Sep 17 00:00:00 2001
From: Jack Grigg <thestr4d@gmail.com>
Date: Tue, 16 Mar 2021 09:47:23 +1300
Subject: [PATCH] poseidon: Clarify that R_F must be even

---
 src/primitives/poseidon.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/primitives/poseidon.rs b/src/primitives/poseidon.rs
index ac5b5975..f2e04935 100644
--- a/src/primitives/poseidon.rs
+++ b/src/primitives/poseidon.rs
@@ -29,6 +29,8 @@ pub trait Spec<F: FieldExt> {
     fn width() -> usize;
 
     /// The number of full rounds for this specification.
+    ///
+    /// This must be an even number.
     fn full_rounds() -> usize;
 
     /// The number of partial rounds for this specification.
@@ -99,7 +101,6 @@ fn permute<F: FieldExt, S: Spec<F>>(
     mds: &[S::State],
     round_constants: &[S::State],
 ) {
-    // TODO: Check what should happen for odd number of full rounds.
     let r_f = S::full_rounds() / 2;
     let r_p = S::partial_rounds();