From ff547369a01a5aa73e4a9d665c5567624795ab17 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ian@liberator.relativity.greenend.org.uk>
Date: Sun, 23 Aug 2009 17:27:07 +0100
Subject: [PATCH] Prefer short trades, using distance table

---
 yarrg/web/routetrade | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/yarrg/web/routetrade b/yarrg/web/routetrade
index fe8459f..8d42537 100644
--- a/yarrg/web/routetrade
+++ b/yarrg/web/routetrade
@@ -35,14 +35,6 @@
 ========== TODO ==========
 16:36 <ceb> alpha,byrne,papaya,turtle,jorvik,luthien is my example
 
-
-- potential cost of losses
-16:37 <ceb> if tehre are 2 rows which take the same object and sell it for the 
-            same profit at two other islands, choose the shortest route as the 
-            preferred one
-16:37 <ceb> coconut buy 10 sell 16, at luthien or jorvik, in that example
-16:38 <ceb> Do you see what I mean?
-
 16:39 <ceb> Also, maybe colour to highlight the suggested trades?
 
 16:40 <ceb> columns should be sortable with the small arrows as before
@@ -53,6 +45,8 @@ use POST for update.  Hrrm.
 
 LATER OR NOT AT ALL
 
+adjustable potential cost of losses (rather than fixed 1e-BIG per league)
+
 max volume/mass
 
 16:38 <ceb> I don't know how hard this is, but can you show only the suggested 
@@ -68,6 +62,8 @@ $qa
 </%args>
 <%perl>
 
+my $loss_per_league= 1e-7;
+
 my @flow_conds;
 my @query_params;
 
@@ -143,6 +139,7 @@ my $stmt= "
 		commods.commodid				commodid,
 		commods.unitmass				unitmass,
 		commods.unitvolume				unitvolume,
+		dist						dist,
 		buy.price - sell.price				unitprofit
 	FROM commods
 	JOIN buy  on commods.commodid = buy.commodid
@@ -153,6 +150,7 @@ my $stmt= "
 	JOIN stalls  as sell_stalls  on sell.stallid  = sell_stalls.stallid
 	JOIN stalls  as buy_stalls   on buy.stallid   = buy_stalls.stallid
 " : "")."
+	JOIN dists on aiid = sell.islandid AND biid = buy.islandid
 	WHERE	(
 		".join("
 	   OR	", @flow_conds)."
@@ -224,6 +222,10 @@ $addcols->({},
 	$f->{"org_stallid"}= $f->{"dst_stallid"}= 'all'
 		if !$qa->{ShowStalls};
 
+	$f->{ExpectedUnitProfit}=
+		$f->{'dst_price'} * (1.0 - $loss_per_league) ** $f->{'dist'}
+		- $f->{'src_price'};
+
 	my @uid= $f->{commodid};
 	foreach my $od (qw(org dst)) {
 		push @uid,
@@ -324,7 +326,9 @@ Maximize
 
   totalprofit:
                   ".(join " +
-                  ", map { "$_->{unitprofit} $_->{Var}" } @flows)."
+                  ", map {
+			sprintf "%.20f %s", $_->{ExpectedUnitProfit}, $_->{Var}
+			} @flows)."
 
 Subject To
 ";
-- 
2.30.2