From 4aec592fb207f5d61b59dc55c5eb71e690bfbe54 Mon Sep 17 00:00:00 2001
From: Lars Mueller <appgurulars@gmx.de>
Date: Sun, 7 Feb 2021 14:01:40 +0100
Subject: [PATCH] Add vector.distance (required by k-d-tree)

---
 vector.lua | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/vector.lua b/vector.lua
index 978e51c..4446718 100644
--- a/vector.lua
+++ b/vector.lua
@@ -134,6 +134,15 @@ function length(v)
     return math.sqrt(norm(v))
 end
 
+-- Minor code duplication for the sake of performance
+function distance(v, other_v)
+    local sum = 0
+    for key, value in pairs(v) do
+        sum = sum + (value - other_v[key]) ^ 2
+    end
+    return math.sqrt(sum)
+end
+
 function normalize(v)
     return divide_scalar(v, length(v))
 end