From ec492bfb7700b719e41553417cbe77c5d10549ae Mon Sep 17 00:00:00 2001
From: fonsinchen <fonsinchen@openttd.org>
Date: Fri, 20 Dec 2013 14:57:44 +0000
Subject: [PATCH] (svn r26166) -Fix: Scale flows only after mapping to avoid
 rounding errors.

---
 src/linkgraph/flowmapper.cpp        | 15 +++++++++------
 src/linkgraph/flowmapper.h          | 13 +++++++++++++
 src/linkgraph/linkgraphschedule.cpp |  4 ++--
 src/station_base.h                  |  2 ++
 src/station_cmd.cpp                 | 16 ++++++++++++++++
 5 files changed, 42 insertions(+), 8 deletions(-)

diff --git a/src/linkgraph/flowmapper.cpp b/src/linkgraph/flowmapper.cpp
index b9aa9cd59c..79e0f09f3f 100644
--- a/src/linkgraph/flowmapper.cpp
+++ b/src/linkgraph/flowmapper.cpp
@@ -18,9 +18,6 @@
  */
 void FlowMapper::Run(LinkGraphJob &job) const
 {
-	/* Time the graph has been running without being compressed. */
-	uint runtime = job.JoinDate() - job.Settings().recalc_time - job.LastCompression();
-
 	for (NodeID node_id = 0; node_id < job.Size(); ++node_id) {
 		Node prev_node = job[node_id];
 		StationID prev = prev_node.Station();
@@ -29,8 +26,6 @@ void FlowMapper::Run(LinkGraphJob &job) const
 			Path *path = *i;
 			uint flow = path->GetFlow();
 			if (flow == 0) break;
-			/* compress to monthly value */
-			flow = max(1U, flow * 30 / runtime);
 			Node node = job[path->GetNode()];
 			StationID via = node.Station();
 			StationID origin = job[path->GetOrigin()].Station();
@@ -51,7 +46,15 @@ void FlowMapper::Run(LinkGraphJob &job) const
 	for (NodeID node_id = 0; node_id < job.Size(); ++node_id) {
 		/* Remove local consumption shares marked as invalid. */
 		Node node = job[node_id];
-		node.Flows().FinalizeLocalConsumption(node.Station());
+		FlowStatMap &flows = node.Flows();
+		flows.FinalizeLocalConsumption(node.Station());
+		if (this->scale) {
+			/* Scale by time the graph has been running without being compressed. */
+			uint runtime = job.JoinDate() - job.Settings().recalc_time - job.LastCompression();
+			for (FlowStatMap::iterator i = flows.begin(); i != flows.end(); ++i) {
+				i->second.ScaleToMonthly(runtime);
+			}
+		}
 		/* Clear paths. */
 		PathList &paths = node.Paths();
 		for (PathList::iterator i = paths.begin(); i != paths.end(); ++i) {
diff --git a/src/linkgraph/flowmapper.h b/src/linkgraph/flowmapper.h
index 6dc84ffea5..6f874e5b30 100644
--- a/src/linkgraph/flowmapper.h
+++ b/src/linkgraph/flowmapper.h
@@ -23,12 +23,25 @@
  */
 class FlowMapper : public ComponentHandler {
 public:
+
+	/**
+	 * Create a flow mapper.
+	 * @param scale Whether the flow mapper should scale all flows to monthly
+	 *              values. Only do that on the very last flow mapping.
+	 */
+	FlowMapper(bool scale) : scale(scale) {}
 	virtual void Run(LinkGraphJob &job) const;
 
 	/**
 	 * Virtual destructor has to be defined because of virtual Run().
 	 */
 	virtual ~FlowMapper() {}
+private:
+
+	/**
+	 * Whether the flow mapper should scale all flows to monthly values.
+	 */
+	const bool scale;
 };
 
 #endif /* FLOWMAPPER_H_ */
diff --git a/src/linkgraph/linkgraphschedule.cpp b/src/linkgraph/linkgraphschedule.cpp
index 366a3c5177..f056d7cfcd 100644
--- a/src/linkgraph/linkgraphschedule.cpp
+++ b/src/linkgraph/linkgraphschedule.cpp
@@ -146,9 +146,9 @@ LinkGraphSchedule::LinkGraphSchedule()
 	this->handlers[0] = new InitHandler;
 	this->handlers[1] = new DemandHandler;
 	this->handlers[2] = new MCFHandler<MCF1stPass>;
-	this->handlers[3] = new FlowMapper;
+	this->handlers[3] = new FlowMapper(false);
 	this->handlers[4] = new MCFHandler<MCF2ndPass>;
-	this->handlers[5] = new FlowMapper;
+	this->handlers[5] = new FlowMapper(true);
 }
 
 /**
diff --git a/src/station_base.h b/src/station_base.h
index c0bb96cd92..a4ad69547e 100644
--- a/src/station_base.h
+++ b/src/station_base.h
@@ -79,6 +79,8 @@ public:
 
 	void ReleaseShare(StationID st);
 
+	void ScaleToMonthly(uint runtime);
+
 	/**
 	 * Get the actual shares as a const pointer so that they can be iterated
 	 * over.
diff --git a/src/station_cmd.cpp b/src/station_cmd.cpp
index 6b158aaf13..6ef602b83f 100644
--- a/src/station_cmd.cpp
+++ b/src/station_cmd.cpp
@@ -4289,6 +4289,22 @@ void FlowStat::ReleaseShare(StationID st)
 	assert(!this->shares.empty());
 }
 
+/**
+ * Scale all shares from link graph's runtime to monthly values.
+ * @param runtime Time the link graph has been running without compression.
+ */
+void FlowStat::ScaleToMonthly(uint runtime)
+{
+	SharesMap new_shares;
+	uint share = 0;
+	for (SharesMap::iterator i = this->shares.begin(); i != this->shares.end(); ++i) {
+		share = max(share + 1, i->first * 30 / runtime);
+		new_shares[share] = i->second;
+		if (this->unrestricted == i->first) this->unrestricted = share;
+	}
+	this->shares.swap(new_shares);
+}
+
 /**
  * Add some flow from "origin", going via "via".
  * @param origin Origin of the flow.