# Controling steppable call frequency. Stopping simulation on demand or increasing maximum Monte Carlo Step.¶

When you create steppable using Twedit++, the editor will plunk template steppable code and will register this steppable in the main Python script. By default such steppable will be called after each completed MCS – as code snippet below shows:

from cellsortingSteppables import cellsortingSteppable

steppableInstance = cellsortingSteppable(sim, _frequency=1)
steppableRegistry.registerSteppable(steppableInstance)


We can change _frequency argument to any non-negative value N to ensure that our steppable gets called every N MCS.

Sometimes in the simulation it may happen that initially you want to call steppable, say, every 50 MCS but later as the simulation goes on you may want to call it every 500 MCS or not call it at all. In such a case all you need to to is to put the following code in the step function:

def step(self,mcs):
...
if mcs > 10000:
self.frequency = 500


This will ensure that after MCS = 10000 the steppable will be called every 500 MCS. If you want to disable steppable completely, you can always set frequency to a number that is greater than MCS and this would do the trick.

On few occasions instead of waiting for a simulation to go through all MCS’s you may have a metric determining if it is sensible to continue simulation or not. In case you want to stop simulation on demand. CC3D has useful function call that does exactly that. Place the following code (CC3D Python->Simulation->Stop Simulation)

self.stopSimulation()


anywhere in the steppable and after this call simulation will get stopped.

Inverse situation may also occur – you want to run simulation for more MCS than originally planned.

In this case you use (CC3D Python->Simulation->SetMaxMCS)

self.setMaxMCS(100000)


to extend simulation to 100000 MCS.