--- a/python/events.py	Wed Jul 22 12:58:04 2015 -0400
+++ b/python/events.py	Wed Jul 22 13:46:28 2015 -0400
@@ -6,7 +6,6 @@
 from base import VideoFilenameAddable
 
 import numpy as np
-from numpy import arccos
 
 import multiprocessing
 import itertools
@@ -182,14 +181,14 @@
             v1 = self.roadUser1.getVelocityAtInstant(instant)
             v2 = self.roadUser2.getVelocityAtInstant(instant)
             deltav = v2-v1
-            velocityAngles[instant] = arccos(moving.Point.dot(v1, v2)/(v1.norm2()*v2.norm2()))
+            velocityAngles[instant] = np.arccos(moving.Point.dot(v1, v2)/(v1.norm2()*v2.norm2()))
             collisionCourseDotProducts[instant] = moving.Point.dot(deltap, deltav)
             distances[instant] = deltap.norm2()
             speedDifferentials[instant] = deltav.norm2()
             if collisionCourseDotProducts[instant] > 0:
                 interactionInstants.append(instant)
             if distances[instant] != 0 and speedDifferentials[instant] != 0:
-                collisionCourseAngles[instant] = arccos(collisionCourseDotProducts[instant]/(distances[instant]*speedDifferentials[instant]))
+                collisionCourseAngles[instant] = np.arccos(collisionCourseDotProducts[instant]/(distances[instant]*speedDifferentials[instant]))
 
         if len(interactionInstants) >= 2:
             self.interactionInterval = moving.TimeInterval(interactionInstants[0], interactionInstants[-1])
@@ -227,7 +226,7 @@
         
         # crossing zones and pPET
         if computeCZ:
-            self.crossingZones[predictionParameters.name] = crossingZones
+            self.crossingZones = crossingZones
             pPETs = {}
             for i, cz in self.crossingZones.iteritems():
                 pPETs[i] = prediction.SafetyPoint.computeExpectedIndicator(cz)
@@ -248,18 +247,11 @@
         else:
             return None
 
-    def getCrossingZones(self, predictionMethodName):
-        if self.crossingZones is not None:
-            return self.crossingZones[predictionMethodName]
-        else:
-            return None
+    def getCollisionPoints(self):
+        return self.collisionPoints
 
-    def getCollisionPoints(self, predictionMethodName):
-        if self.collisionPoints is not None:
-            return self.collisionPoints[predictionMethodName]
-        else:
-            return None
-
+    def getCrossingZones(self):
+        return self.crossingZones
 
 def createInteractions(objects, _others = None):
     '''Create all interactions of two co-existing road users'''
@@ -288,22 +280,19 @@
     else:
         return None
 
-def aggregateSafetyPoints(interactions, predictionMethodName = None, pointType = 'collision'):
+def aggregateSafetyPoints(interactions, pointType = 'collision'):
     '''Put all collision points or crossing zones in a list for display'''
-    if predictionMethodName is None and len(interactions)>0:
-        predictionMethodName = interactions[0].collisionPoints.keys()[0]
-
     allPoints = []
     if pointType == 'collision':
         for i in interactions:
-            for points in i.collisionPoints[predictionMethodName].values():
+            for points in i.collisionPoints.values():
                 allPoints += points
     elif pointType == 'crossing':
         for i in interactions:
-            for points in i.crossingZones[predictionMethodName].values():
+            for points in i.crossingZones.values():
                 allPoints += points
     else:
-        print('unknown type of point '+pointType)
+        print('unknown type of point: '+pointType)
     return allPoints
 
 def prototypeCluster(interactions, similarityMatrix, alignmentMatrix, indicatorName, minSimilarity):