Relocate diffusion_limiter import in simulate.py to avoid circular import

Author: alongd

rmgpy/tools/simulate.py

@@ -32,7 +32,6 @@
 from time import time
 
 import rmgpy.util as util
-from rmgpy.kinetics.diffusionLimited import diffusion_limiter
 from rmgpy.rmg.listener import SimulationProfileWriter, SimulationProfilePlotter
 from rmgpy.rmg.main import initialize_log
 from rmgpy.rmg.settings import ModelSettings
@@ -48,6 +47,7 @@ def simulate(rmg, diffusion_limited=True):
     diffusion_limited=True implies that if it is a liquid reactor diffusion limitations will be enforced
     otherwise they will not be in a liquid reactor
     """
+    from rmgpy.kinetics.diffusionLimited import diffusion_limiter
     util.make_output_subdirectory(rmg.output_directory, 'solver')
 
     for index, reaction_system in enumerate(rmg.reaction_systems):