CSR Runners

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The run parameters of a Simulation are conveyed to theModel by means of a Runner. Rather than simply being a list of time-parameters, runners can be extended to add quite interesting model behaviour without changing a line of code to the model itself.

note: this concept is under development and subject to changes

starting the model

To start a model run, call runModel() in the unit model.py. he unit runCSR.py is the prefered place to set up and activate the runner.

without a runner

The Model is always started with a runner which is passed to runModel(). If this function is called without arguments, a default runner is created that will run the model for 365 days.

with a runner

The Runner-class is co-developed with Model and therefore it resides in model.py, too. An instance of Runner can be created and passed to runModel() to run the model for an other period than 365 days.

The class's constructor is

def __init__(self, days = 365, years = 0, startTime = 1):

  • days: # days to run, in addition to years
  • years: # years to run, in addition to days
  • startTime: day number of the starting day

example, to run for approx. 1.5 years
runModel(Runner(days = 180, years = 1))
# alternative way:
runner = Runner(days = 180, years = 1)

creating a custom runner

Runner can be subclassed to implement custom behaviour. Examples are bypassing the standard initialisation, and defining output events. The methods available are:

def identification(self):
    Shown at the beginning of a simulation run, each subclassed Runner
    ought to define its own identification line. 
    @return: string
    return <identification statement>
  def doAfterModelConstruction(self, system):
  def doSetUpComplete(self, system):
  def doInitialized(self, system):
  def doStartTimeStep(self, system, time):
  def doEndTimeStep(self, system, time):
  def doEndRun(self, system):

Each subclass must override identification() to feed back to the user which Runner is in charge. The other methods are called at specific moments during the simulation and optional to override.

example: output

simple output example
  def doInitialized(self, system):
    self._system = system
    for state in getGlobalStateList():
      state.onIntegration = self.printIntegrands
  def printIntegrands(self, state, effective_rate, value):
    print "%s of %s (t=%f):" % (state.name, state.owner, self._system.time)
    print "   ", value, "+", effective_rate, "=", value + effective_rate,
    print "[%s]" % (state.units if len(state.units) > 0 else '?')

example: inteurupt execution

simple output example
  def doInitialized(self, system):
    sys.exit("%s will only run upto initialization" % (self.__class__.__name__))

example: bypass initialization

change initialization of patches
  def doAfterModelConstruction(self, modelSystem):
    modelSystem.modelArea.builder = BareSoilInitializer()

see also