pg.evolution.Mutator

Accessible via pg.evolution.Mutator.

class Mutator[source]

Bases: pg.evolution.DNAOperation

Base class for mutators.

A mutator performs a mutation, i.e. a random transformation that converts a parent DNA to a child DNA. Mutations should reach the full search space through composition and should prefer local transformations individually.

Methods:

mutate(dna, global_state[, step])

Mutates the DNA at a given step.

mutate_list(dna_list, global_state[, step])

Mutate the DNA in the input one by one and concatenate their outputs.

Attributes:

operation_method

Returns a member method as operation.
mutate(dna, global_state, step=0)[source]

Mutates the DNA at a given step.

User should override this method or mutate_list method with optional keyword arguments ‘global_state’ and ‘step’.

Return type:

Union[pg.DNA, List[pg.DNA]]

Parameters:

  • dna – DNA to mutate.

  • global_state – An AttributeDict object as the container of global states.

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

Returns:

A new DNA or a DNA list as the result of the mutation.

mutate_list(dna_list, global_state, step=0)[source]

Mutate the DNA in the input one by one and concatenate their outputs.

User should override this method instead of mutate if mutation depends on the list-wise information. Keyword arguments global_state and step are optional when override.

Return type:

List[pg.DNA]

Parameters:

  • dna_list – a list of DNA to mutate.

  • global_state – An AttributeDict object as the container of global states.

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

Returns:

a list of DNA as the result of the mutation.

property operation_method[source]

Returns a member method as operation.