# HG changeset patch
# User Nicolas Saunier <nicolas.saunier@polymtl.ca>
# Date 1396297213 14400
# Node ID 7828fec8bbd2bf195476431f6063e84f002431b1
# Parent  d337bffd7283a16fc81bbf948a47ffbf0a47b104
added function to generate headways based on flow or mean headway over some simulation period

diff -r d337bffd7283 -r 7828fec8bbd2 python/traffic_engineering.py
--- a/python/traffic_engineering.py	Thu Mar 27 11:40:28 2014 -0400
+++ b/python/traffic_engineering.py	Mon Mar 31 16:20:13 2014 -0400
@@ -12,6 +12,20 @@
 # Simulation
 #########################
 
+def generateTimeHeadways(meanTimeHeadway, simulationTime):
+    '''Generates the time headways between arrivals 
+    given the meanTimeHeadway and the negative exponential distribution
+    over a time interval of length simulationTime (assumed to be in same time unit as headway'''
+    from random import expovariate
+    headways = []
+    totalTime = 0
+    flow = 1/meanTimeHeadway
+    while totalTime < simulationTime:
+        h = expovariate(flow)
+        headways.append(h)
+        totalTime += h
+    return headways
+
 class Vehicle:
     '''Generic vehicle class
     1D coordinates for now'''