From 9632bea377f0bd8c931c27c67e835d9cfe552023 Mon Sep 17 00:00:00 2001
From: Rob Rix <rob.rix@github.com>
Date: Tue, 5 Jul 2016 09:26:34 -0400
Subject: [PATCH] :memo: vmagnitude.

---
 src/Data/RandomWalkSimilarity.hs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/Data/RandomWalkSimilarity.hs b/src/Data/RandomWalkSimilarity.hs
index 5bbb6b82f..6b1cea492 100644
--- a/src/Data/RandomWalkSimilarity.hs
+++ b/src/Data/RandomWalkSimilarity.hs
@@ -88,6 +88,7 @@ featureVector d bag = sumVectors $ unitDVector . hash <$> bag
         normalize vec = fmap (/ vmagnitude vec) vec
         sumVectors = DList.foldr (Vector.zipWith (+)) (Vector.replicate d 0)
 
+-- | The magnitude of a Euclidean vector, i.e. its distance from the origin.
 vmagnitude :: Vector.Vector Double -> Double
 vmagnitude = sqrtDouble . Vector.sum . fmap (** 2)