Tweaking cantera simulation advance code (shouldn't advance beyond en…

…d time)

source/rmg/model.py

@@ -894,8 +894,8 @@ def simulate(self, model):
 		P = gas.pressure()
 		V = sim.reactors()[0].volume()
 		T = gas.temperature()
-		# recall that Cantera returns molarDensity() in units of kmol/m3
-		# and this program thinks in mol/m3
+		# Note that, for molar density, Cantera thinks in kmol/m^3, while
+		# RMG thinks in mol/m^3
 		Ni = gas.molarDensity()*1000.0 * gas.moleFractions() * V 
 		y = [P, V, T]; y.extend(Ni)
 		Ni0 = Ni
@@ -920,11 +920,13 @@ def simulate(self, model):
 				first_step = False # don't integrate on first time through, just do the validity checking and result reporting
 			else:
 				# Uses a fixed (on a log scale) time step
-				nexttime = time*1.2589254117941673
+				nexttime = min(endtime,time*1.2589254117941673)
 				try:
-					# advance cantera one step, or two if the first didn't get there
-					if sim.step(endtime) < endtime:
+					# advance cantera one step
+					if sim.step(endtime) < endtime: 
+						# didn't get to endtime, so take another step
 						if sim.step(endtime) < nexttime:
+							# still didn't get to endtime, so advance to nextime
 							sim.advance(nexttime)
 #				# Uses the same time steps that the Cantera solver used
 #				try:
@@ -933,7 +935,7 @@ def simulate(self, model):
 					logging.exception("Ignoring Cantera error")
 					logging.debug(e.message)
 					pass
-
+			
 			# Get state at current time
 			time = sim.time()
 			P = gas.pressure()