Added Manhattan distance

Yonaba · Yonaba · commit 12c08b094ade · 2014-03-30T21:23:27.000Z
diff --git a/Manhattan_distance/Lua/Yonaba/manhattan_distance.lua b/Manhattan_distance/Lua/Yonaba/manhattan_distance.lua
@@ -0,0 +1,18 @@
+-- Manhattan distance distance implementation
+-- See: http://xlinux.nist.gov/dads//HTML/manhattanDistance.html
+-- See: http://en.wikipedia.org/wiki/Manhattan_distance
+
+-- Returns the Manhattan distance between two vectors
+-- p       : a first vector
+-- q       : a second vector
+-- returns : the distance between p and q
+local function manhattan_distance(p, q)
+  assert(#p == #q, 'vectors must have the same length')
+  local s = 0
+  for i in ipairs(p) do
+    s = s + math.abs(p[i] - q[i])
+  end
+  return s
+end
+
+return manhattan_distance
