From 538c2ae0668ae9e7de41034ea59d6f5e5a6ffd27 Mon Sep 17 00:00:00 2001
From: dave <dave>
Date: Mon, 22 Feb 2010 18:13:11 +0000
Subject: [PATCH] Use array_splice to compute new lists... much shorter code,
 and probably a lot faster.

---
 admin/anneal.inc.php | 55 +++++++++++++++++++-------------------------
 1 file changed, 24 insertions(+), 31 deletions(-)

diff --git a/admin/anneal.inc.php b/admin/anneal.inc.php
index 1b7c1e3..c7a16ba 100644
--- a/admin/anneal.inc.php
+++ b/admin/anneal.inc.php
@@ -12,6 +12,7 @@ class annealer {
 	var $update_callback;
 	var $iterations;
 	var $items_per_bucket;
+	var $max_items_per_bucket;
 	var $rate;
 	
 	function annealer($num_buckets, $start_temp, $start_moves, $rate,
@@ -29,6 +30,7 @@ class annealer {
 		$this->iterations = 0;
 		$this->items_per_bucket = count($items) / $num_buckets;
 		$this->rate = $rate;
+		$this->max_items_per_bucket = 0;
 		$ipb = ceil($this->items_per_bucket);
 		$i=0;
 		$this->cost = 0;
@@ -59,6 +61,10 @@ class annealer {
 	{
 		$this->update_callback = $func;
 	}
+	function set_max_items_per_bucket($num) 
+	{
+		$this->max_items_per_bucket = $num;
+	}
 
 
 	function pick_move()
@@ -70,13 +76,20 @@ class annealer {
 		}
 		$i1 = rand(0, count($this->bucket[$b1]) -1);
 
-		/* Pick a csecond bucket that is different thatn the first */
+		/* Pick a second bucket that is different than the first */
 		$b2 = rand(0, $this->num_buckets - 2);
 		if($b2 >= $b1) $b2++;
-	
-		/* Picket an item, or a blank, in the second bucket */
-		$i2 = rand(0, count($this->bucket[$b2]));
-		if($i2 == count($this->bucket[$b2])) $i2 = -1;
+
+		
+		if($this->max_items_per_bucket > 0 && count($this->bucket[$b2]) >= $this->max_items_per_bucket) {
+			/* Can't move b1 into b2, it would exceed the max items per bucket, pick an
+			 * item to swap with */
+			$i2 = rand(0, count($this->bucket[$b2])-1);
+		} else {
+			/* Pick an item, or a blank, in the second bucket */
+			$i2 = rand(0, count($this->bucket[$b2]));
+			if($i2 == count($this->bucket[$b2])) $i2 = -1;
+		}
 //		TRACE("Move ($b1,$i1)<->($b2,$i2)\n");
 		return array($b1, $i1, $b2, $i2);
 	}
@@ -104,33 +117,13 @@ class annealer {
 		$b1_old = $this->bucket[$b1];
 		$b2_old = $this->bucket[$b2];
 		
-		$b1_new = array();
-		$b2_new = array();
-		/* Make 2 new bucket lists */
-		for($x=0; $x<count($b1_old); $x++) {
-			$id = $b1_old[$x];
-			if($x == $i1) {
-				/* Swap or remove this index */
-				if($i2 != -1) $b1_new[] = $b2_old[$i2];
-			} else {
-				$b1_new[] = $id;
-			}
+		if($i2 != -1) {
+			array_splice($this->bucket[$b1], $i1, 1, $b2_old[$i2]);
+			array_splice($this->bucket[$b2], $i2, 1, $b1_old[$i1]);
+		} else {
+			array_splice($this->bucket[$b1], $i1, 1);
+			$this->bucket[$b2][] = $b1_old[$i1];
 		}
-		for($x=0; $x<count($b2_old); $x++) {
-			$id = $b2_old[$x];
-			if($x == $i2) {
-				/* Swap or remove this index */
-				$b2_new[] = $b1_old[$i1];
-			} else {
-				$b2_new[] = $id;
-			}
-		}
-		if($i2 == -1) $b2_new[] = $b1_old[$i1];
-		
-
-		/* Assign the new item lists to the buckets */
-		$this->bucket[$b1] = $b1_new;
-		$this->bucket[$b2] = $b2_new;
 
 		/* Compute costs */
 		$cost -= $this->bucket_cost[$b1];