pg.evolution.SymmetricDifference

Accessible via pg.evolution.SymmetricDifference.

class SymmetricDifference(ops)[source]

Bases: pg.evolution.Operation

Compute the symmetric difference of operation outputs based on the input.

A symmetric difference operation passes the input to all its child selectors, and include the items that only appear in a single operation output. The items in the output will follow the order of their presences in the input.

Example:

pg.evolution.SymmetricDifference([
  pg.evolution.selectors.Top(10),
  pg.evolution.selectors.First(10)
])

which is equivalent to:

pg.evolution.selectors.Top(10) ^ pg.evolution.selectors.First(10)

The code above returns items that are either among the top 10 or among the first 10 but not both.

Methods:

call(inputs, global_state[, step])

Subclasses should override this method.
call(inputs, global_state, step=0)[source]

Subclasses should override this method.

The global_state and step are optional for the subclasses’ call signature.

Return type:

List[Any]

Parameters:

  • inputs – A list of values as inputs.

  • global_state – An AttributeDict object as the global state container, which is readable/writable during the operation.

  • step – Number of examples historically proposed, which can be used for determining a cross over schedule.

Returns:

A list of values as output of current operation.