From fdffdd82ddc7f99beb714b244d090f1d8e9dc2c0 Mon Sep 17 00:00:00 2001
From: Samuel Tardieu <sam@rfc1149.net>
Date: Sat, 6 Mar 2010 14:37:35 +0100
Subject: [PATCH] Use a better heuristic

---
 extra/astar/astar-tests.factor | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/extra/astar/astar-tests.factor b/extra/astar/astar-tests.factor
index 6dd27cf372..11b2dfcaa2 100644
--- a/extra/astar/astar-tests.factor
+++ b/extra/astar/astar-tests.factor
@@ -34,11 +34,14 @@ IN: astar.tests
      4array
      [ reachable? ] filter ;
 
+: heuristic ( from to -- cost )
+    v- [ abs ] [ + ] map-reduce ;
+
 : cost ( from to -- cost )
     2dup [ first ] bi@ = [ [ second ] bi@ > 1 5 ? ] [ 2drop 2 ] if ;
 
 : test1 ( to -- path considered )
-    { 1 1 } swap [ neighbours ] [ cost ] [ distance ] <astar> [ find-path ] [ considered ] bi ;
+    { 1 1 } swap [ neighbours ] [ cost ] [ heuristic ] <astar> [ find-path ] [ considered ] bi ;
 >>
 
 ! Existing path from s to f