From e77b01f9fed6d5f653dbd0123f0f1f61a13c3dfa Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sat, 21 May 2011 10:35:33 +0000
Subject: [PATCH] Don't use too short speed measurements for quantizer learning
 Wait for enough learning data before using it for quantization

---
 source/libr2c2/speedquantizer.cpp | 11 ++++++-----
 source/libr2c2/speedquantizer.h   |  1 +
 source/libr2c2/train.cpp          |  2 +-
 3 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/source/libr2c2/speedquantizer.cpp b/source/libr2c2/speedquantizer.cpp
index 710e104..acd1983 100644
--- a/source/libr2c2/speedquantizer.cpp
+++ b/source/libr2c2/speedquantizer.cpp
@@ -13,7 +13,8 @@ using namespace Msp;
 namespace R2C2 {
 
 SpeedQuantizer::SpeedQuantizer(unsigned n):
-	steps(n+1)
+	steps(n+1),
+	weight_limit(10)
 {
 	if(n<1)
 		throw InvalidParameterValue("Must have at leats one speed step");
@@ -30,16 +31,16 @@ float SpeedQuantizer::get_speed(unsigned i) const
 {
 	if(i==0)
 		return 0;
-	if(steps[i].weight)
+	if(steps[i].weight>=weight_limit)
 		return steps[i].speed;
 
 	unsigned low;
 	unsigned high;
 	for(low=i; low>0; --low)
-		if(steps[low].weight)
+		if(steps[low].weight>=weight_limit)
 			break;
 	for(high=i; high+1<steps.size(); ++high)
-		if(steps[high].weight)
+		if(steps[high].weight>=weight_limit)
 			break;
 
 	if(steps[high].weight)
@@ -69,7 +70,7 @@ unsigned SpeedQuantizer::find_speed_step(float speed) const
 	unsigned high = 0;
 	unsigned last = 0;
 	for(unsigned i=0; (!high && i<steps.size()); ++i)
-		if(steps[i].weight)
+		if(steps[i].weight>=weight_limit)
 		{
 			last = i;
 			if(steps[i].speed>=speed)
diff --git a/source/libr2c2/speedquantizer.h b/source/libr2c2/speedquantizer.h
index d6dc1ac..2f9aedd 100644
--- a/source/libr2c2/speedquantizer.h
+++ b/source/libr2c2/speedquantizer.h
@@ -36,6 +36,7 @@ private:
 	};
 
 	std::vector<SpeedStep> steps;
+	float weight_limit;
 
 public:
 	SpeedQuantizer(unsigned);
diff --git a/source/libr2c2/train.cpp b/source/libr2c2/train.cpp
index 93ebebe..ba1a861 100644
--- a/source/libr2c2/train.cpp
+++ b/source/libr2c2/train.cpp
@@ -763,7 +763,7 @@ void Train::block_state_changed(Block &block, Block::State state)
 			// Compute speed and update related state
 			float travel_time_secs = (Time::now()-last_entry_time)/Time::sec;
 
-			if(pure_speed && speed_quantizer && current_speed_step>0)
+			if(pure_speed && speed_quantizer && current_speed_step>0 && travel_time_secs>=2)
 				speed_quantizer->learn(current_speed_step, travel_dist/travel_time_secs, travel_time_secs);
 
 			travel_dist = 0;
-- 
2.43.0