"""
====================
Randomness Interface
====================
This module provides an interface to the :class:`RandomnessManager <vivarium.framework.randomness.manager.RandomnessManager>`.
"""
from __future__ import annotations
import pandas as pd
from vivarium.framework.randomness.manager import RandomnessManager
from vivarium.framework.randomness.stream import RandomnessStream
from vivarium.manager import Interface
[docs]
class RandomnessInterface(Interface):
def __init__(self, manager: RandomnessManager):
self._manager = manager
[docs]
def get_stream(
self,
decision_point: str,
initializes_crn_attributes: bool = False,
) -> RandomnessStream:
"""Provides a new source of random numbers for the given decision point.
Vivarium provides a Common Random Number framework which
allows for variance reduction when modeling counter-factual scenarios.
Users interested in causal analysis and comparisons between simulation
scenarios should be careful to use randomness streams provided by the
framework wherever randomness is employed.
Parameters
----------
decision_point
A unique identifier for a stream of random numbers. Typically, this
represents a decision that needs to be made each time step like
'moves_left' or 'gets_disease'.
initializes_crn_attributes
A flag indicating whether this stream is used to generate key
initialization information that will be used to identify simulants
in the Common Random Number framework. These streams cannot be
copied and should only be used to generate the state table columns
specified in ``builder.configuration.randomness.key_columns``.
Returns
-------
An entry point into the Common Random Number framework.
The stream provides vectorized access to random numbers and a few
other utilities.
"""
return self._manager.get_randomness_stream(decision_point, initializes_crn_attributes)
[docs]
def get_seed(self, decision_point: str) -> int:
"""Gets a randomly generated seed for use with external randomness tools.
Parameters
----------
decision_point
A unique identifier for a stream of random numbers. Typically
represents a decision that needs to be made each time step like
'moves_left' or 'gets_disease'.
Returns
-------
A seed for a random number generation that is linked to Vivarium's
Common Random Number framework.
"""
return self._manager.get_seed(decision_point)
[docs]
def register_simulants(self, simulants: pd.DataFrame) -> None:
"""Registers simulants with the Common Random Number framework.
Parameters
----------
simulants
A section of the state table with new simulants and at least the
columns specified in
``builder.configuration.randomness.key_columns``. This function
should be called as soon as the key columns are generated.
"""
self._manager.register_simulants(simulants)