From: ian <ian>
Date: Fri, 16 May 2008 19:03:45 +0000 (+0000)
Subject: rounding errors
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ijackson/git?a=commitdiff_plain;h=813b3a8fb0b1635e82e9be280f257bfa512481b0;p=trains.git

rounding errors
---

diff --git a/hostside/safety.h b/hostside/safety.h
index 2e88f13..7c07b4d 100644
--- a/hostside/safety.h
+++ b/hostside/safety.h
@@ -363,5 +363,6 @@ int trackloc_set_exactinto(TrackLocation *t, TrackAdvanceContext *c,
 #define MARGIN_STOPTIME 50 /*ms*/
 #define MARGIN_AUTOPOINTTIME 500 /*ms*/
 #define MARGIN_POLARISETIME 50 /*ms*/
+#define UNMARGIN_ROUNDING 1e-4 /* mm/ms; for 1s, leads to max err of 100um */
 
 #endif /*SAFETY_H*/
diff --git a/hostside/speed.c b/hostside/speed.c
index 43175b6..627eff5 100644
--- a/hostside/speed.c
+++ b/hostside/speed.c
@@ -22,7 +22,7 @@ static void decel_done(TimeoutEvent *toev) {
 static const SpeedRange *stop_info(Train *tra, double speed) {
   int i;
   for (i=0; i<tra->n_speedregimes; i++)
-    if (speed <= tra->speedregimes[i].speed)
+    if (speed <= tra->speedregimes[i].speed + UNMARGIN_ROUNDING)
       return &tra->speedregimes[i];
   abort();
 }