--- a/python/events.py	Fri Mar 29 21:20:12 2013 -0400
+++ b/python/events.py	Tue Apr 02 15:27:42 2013 -0400
@@ -3,6 +3,7 @@
 Interactions, pedestrian crossing...'''
 
 import numpy as np
+from numpy import arccos
 
 import multiprocessing
 import itertools
@@ -50,17 +51,19 @@
             deltap = self.movingObject1.getPositionAtInstant(instant)-self.movingObject2.getPositionAtInstant(instant)
             deltav = self.movingObject2.getVelocityAtInstant(instant)-self.movingObject1.getVelocityAtInstant(instant)
             collisionCourseDotProducts[instant] = moving.Point.dot(deltap, deltav)
-            distances[instant] = deltap.norm2()
+            distances[instant] = deltap.norm2() # todo compute closest feature distance, if features
             speedDifferentials[instant] = deltav.norm2()
             if collisionCourseDotProducts[instant] > 0:
-                collisionCourseCosines[instant] = collisionCourseDotProducts[instant]/(distances[instant]*speedDifferentials[instant])
+                collisionCourseCosines[instant] = arccos(collisionCourseDotProducts[instant]/(distances[instant]*speedDifferentials[instant]))
+
         # todo shorten the time intervals based on the interaction definition
-        # todos change cosines to angles
         self.addIndicator(indicators.SeverityIndicator('Collision Course Dot Product', collisionCourseDotProducts))
         self.addIndicator(indicators.SeverityIndicator('Distance', distances))
         self.addIndicator(indicators.SeverityIndicator('Speed Differential', speedDifferentials))
         self.addIndicator(indicators.SeverityIndicator('Collision Course Cosine', collisionCourseCosines))
 
+        # todo test for interaction instants and interval, compute indicators
+
 
 def createInteractions(objects):
     '''Create all interactions of two co-existing road users