Intervention

class Intervention(label=None, show_label=False, do_plot=None, line_args=None)

Bases: object

Base class for interventions. By default, interventions are printed using a dict format, which they can be recreated from. To display all the attributes of the intervention, use disp() instead.

To retrieve a particular intervention from a sim, use sim.get_intervention().

Parameters:

• label (str) – a label for the intervention (used for plotting, and for ease of identification)

• show_label (bool) – whether or not to include the label in the legend

• do_plot (bool) – whether or not to plot the intervention

• line_args (dict) – arguments passed to pl.axvline() when plotting

Methods

disp()

Print a detailed representation of the intervention

initialize(sim=None)

Initialize intervention – this is used to make modifications to the intervention that can’t be done until after the sim is created.

finalize(sim=None)

Finalize intervention

This method is run once as part of sim.finalize() enabling the intervention to perform any final operations after the simulation is complete (e.g. rescaling)

apply(sim)

Apply the intervention. This is the core method which each derived intervention class must implement. This method gets called at each timestep and can make arbitrary changes to the Sim object, as well as storing or modifying the state of the intervention.

Parameters:

sim – the Sim instance

Returns:

None

shrink(in_place=False)

Remove any excess stored data from the intervention; for use with sim.shrink().

Parameters:

in_place (bool) – whether to shrink the intervention (else shrink a copy)

plot_intervention(sim, ax=None, **kwargs)

Plot the intervention

This can be used to do things like add vertical lines on days when interventions take place. Can be disabled by setting self.do_plot=False.

Note 1: you can modify the plotting style via the line_args argument when creating the intervention.

Note 2: By default, the intervention is plotted at the days stored in self.days. However, if there is a self.plot_days attribute, this will be used instead.

Parameters:

• sim – the Sim instance

• ax – the axis instance

• kwargs – passed to ax.axvline()

Returns:

None

to_json()

Return JSON-compatible representation

Custom classes can’t be directly represented in JSON. This method is a one-way export to produce a JSON-compatible representation of the intervention. In the first instance, the object dict will be returned. However, if an intervention itself contains non-standard variables as attributes, then its to_json method will need to handle those.

Note that simply printing an intervention will usually return a representation that can be used to recreate it.

Returns:

JSON-serializable representation (typically a dict, but could be anything else)