From 37efb139eefe5da374701c9c1669d1e38aba38f3 Mon Sep 17 00:00:00 2001
From: Mark Tearle <mtearle@ucc.asn.au>
Date: Sat, 13 Dec 2014 21:00:48 +0800
Subject: [PATCH] Modify idler selection algorithm

---
 VendServer/VendServer.py | 38 ++++++++++++++++++++++++--------------
 1 file changed, 24 insertions(+), 14 deletions(-)

diff --git a/VendServer/VendServer.py b/VendServer/VendServer.py
index a009da7..0962697 100755
--- a/VendServer/VendServer.py
+++ b/VendServer/VendServer.py
@@ -288,23 +288,33 @@ def reset_idler(v, vstatus, t = None):
 
 def choose_idler():
 	global idlers, idler
-	iiindex = 0
-	average_affinity = 10 # guessing here...
 
-	if idler and idler.__class__ != GreetingIdler:
-		iiindex = idlers.index(idler)
-
-	iilen = len(idlers)
-
-	move = int(random()*len(idlers)*average_affinity) + 1
+	# Implementation of the King Of the Hill algorithm from;
+	# http://eli.thegreenplace.net/2010/01/22/weighted-random-generation-in-python/
+
+	#def weighted_choice_king(weights):
+	#	total = 0
+	#	winner = 0
+	#	for i, w in enumerate(weights):
+	#		total += w
+	#		if random.random() * total < w:
+	#			winner = i
+	#	return winner
+	#	
+
+	total = 0
+	winner = None
+	
+	for choice in idlers:
+		weight = choice.affinity()
+		total += weight
+		if random() * total < weight:
+			winner = choice
 
-	while move >= 0:
-		iiindex += 1
-		iiindex %= iilen
-		idler = idlers[iiindex]
-		move -= idler.affinity()
+	idler = winner
 
-	idler.reset()
+	if idler:
+		idler.reset()
 
 def idle_step(vstatus):
 	global idler
-- 
2.20.1