Selection Policy

The SelectionManager is the owner of SelectionPolicies and will use them to execute sql queries to the database.

The SelectionManager has a 1-1 relationship with the CalibrationStore, new configurable policies can be injected into the manager from the tango interface using UpdateSelectionPolicy

SelectionManager(logger)	A SelectionManager.
SelectPreferred(logger, *args, **kwargs)	A SelectPreferred policy preferred.
SelectClosestInRange(logger, *args, **kwargs)	A SelectClosestInRange policy closest_in_range.

This subpackage implements calibration store functionality for MCCS.

class SelectClosestInRange(logger: Logger, *args: Any, **kwargs: Any)

A SelectClosestInRange policy closest_in_range.

A solution is selected from a set of tolerances. The most recent solution within these tolerances is chosen. If more than one solutions tie we yield the one with the smallest absolute summed difference.

>>>    "SELECT frequency_channel, outside_temperature, "
>>>    "calibration_path, creation_time, station_id, preferred "
>>>    "FROM tab_mccs_calib "
>>>    f"WHERE station_id = {station_id} "
>>>    f"AND frequency_channel >= {frequency_channel-self.frequency_tolerance} "
>>>    f"AND frequency_channel <= {frequency_channel+self.frequency_tolerance} "
>>>    "AND outside_temperature >= "
>>>    f"{outside_temperature-self.temperature_tolerance} "
>>>    "AND outside_temperature <= "
>>>    f"{outside_temperature+self.temperature_tolerance} "
>>>    "ORDER BY preferred DESC, "
>>>    "creation_time DESC, "
>>>    f"ABS(ABS(frequency_channel-{frequency_channel}) "
>>>    f"+ ABS(outside_temperature-{outside_temperature})) DESC"

configure(temperature_tolerance: float = 0.0, frequency_tolerance: int = 0) → None

Configure the SelectClosestInRange policy.

Parameters:

• temperature_tolerance – the absolute temperature tolerance.

• frequency_tolerance – the absolute frequency tolerance.

generate_sql(outside_temperature: float, frequency_channel: int, station_id: int, **kwargs: Any) → str

Return an sql query.

Parameters:

• outside_temperature – The current outside temperature.

• frequency_channel – The current frequency channel.

• station_id – The id of the station we want a solution for.

• kwargs – kwargs

Returns:

a sql query.

class SelectPreferred(logger: Logger, *args: Any, **kwargs: Any)

A SelectPreferred policy preferred.

The most recent solution within a defined frequency tolerance with the field preferred == TRUE is chosen. If none defined as preferred, no solution is returned.

>>>    "SELECT frequency_channel, outside_temperature, "
>>>    "calibration_path, creation_time, station_id, preferred "
>>>    "FROM tab_mccs_calib "
>>>    f"WHERE station_id = {station_id} "
>>>    f"AND frequency_channel >= {frequency_channel-self.frequency_tolerance} "
>>>    f"AND frequency_channel <= {frequency_channel+self.frequency_tolerance} "
>>>    "AND preferred = TRUE "
>>>    "ORDER BY creation_time DESC"

configure(frequency_tolerance: int = 0) → None

Configure the SelectPreferred policy.

Parameters:

frequency_tolerance – the absolute frequency tolerance.

generate_sql(station_id: int, frequency_channel: int, **kwargs: Any) → str

Return an sql query.

Parameters:

• station_id – The id of the station we want a solution for.

• frequency_channel – The current frequency channel.

• kwargs – kwargs

Returns:

a sql query.

class SelectionManager(logger: Logger)

A SelectionManager.

__init__(logger: Logger) → None

Initialise a new SelectionManager.

Parameters:

logger – A logger for information purposes.

get_solution(connection: Any, **kwargs: Any) → list[float]

Get a solution using the loaded SelectionPolicy.

This will return a solution from a query set by the loaded SelectionPolicy

Parameters:

• connection – the database connection.

• kwargs – kwargs to feed the selection policy

Returns:

the solution or an empty list.

Raises:

ValueError – then there is no configured policy to use.

property has_policy: bool

Return whether policy is defined.

Returns:

True if policy is not None.

property policy: str

Return the policy description.

Returns:

information about the selection policy.

update_policy(policy: SelectPreferred | SelectClosestInRange) → None

Set a new policy.

Parameters:

policy – the sql to use.