Simulation, Computation

Simulation: the framework of computation

A Simulation is basically the OpenFisca frame for calculating taxes or benefits.

To calculate any variable you need to create a Simulation from the TaxBenefitSystem that is to say the framework where you will compute your result.

Technically speaking it is the cache of input data and previously computed results.

It’s possible to run many independent simulations using the same TaxBenefitSystem.

Application: how to launch a simulation

As soon as you’ve loaded the TaxBenefitSystem of a country and a Scenario, you may now create a simulation.

# Create a simulation from a scenario
simulation = scenario.new_simulation()

Computing variables

Now all the settings are given to run computation of taxes or benefits.

WARNING: Be aware of the period over which you want to have your result. Some measures are calculated on a monthly basis other an annual one.

For further information: see the tutorial “How to handle periods”

Application: how to calculate a variable

# Calcul of the 'impot sur le revenu des personnes physiques'
impot = simulation.calculate('irpp', '2015')
allocations_familiales = simulation.calculate('af', '2015-01')

HINT: Don’t forget to give the period.

The output is an array:

• positive if it is an amount the entity receives from the state.
• negative if it is an amount the entity has to pay.