Hi All
Here is a sample use of two options.
*Option1*: Declaring factory interface in MutationPolicy, CrossoverPolicy
and SelectionPolicy. A sample implementation has been shown here for
MutationPolicy. Similar would be required for all other relevant interfaces
and implemented classes.
--CUT--
public interface MutationPolicy<P> {
Chromosome<P> mutate(Chromosome<P> original, double mutationRate);
interface Factory<P> {
/**
* Creates an instance with a dedicated source of randomness.
*
* @param rng RNG algorithm.
* @param seed Seed.
* @return an instance that must <em>not</em> be shared among
threads.
*/
MutationPolicy<P> create(RandomSource rng, Object... args);
default MutationPolicy<P> create(RandomSource rng) {
return create(rng, null);
}
default MutationPolicy<P> create() {
return create(RandomSource.SPLIT_MIX_64);
}
}
}
//Implementation Class
public class IntegralValuedMutation<P> implements MutationPolicy<P> {
private final UniformRandomProvider provider;
private IntegralValuedMutation(RandomSource rng) {
provider = ThreadLocalRandomSource.current(rng);
}
...
...
public static class MutationFactory<Q> implements Factory<Q> {
private static final MutationFactory instance = new
MutationFactory<>();
private MutationFactory() {}
@Override
public MutationPolicy<Q> create(RandomSource rng, Object... args) {
return new IntegralValuedMutation<>(args[0], args[1]);
}
public static <Q> MutationFactory<Q> getInstance() {
return instance;
}
}
//Usage
MutationPolicy<Integer> policy =
IntegralValuedMutation.MutationFactory.<Integer>getInstance().create();
--CUT--
Option2: Optional constructor argument can also be used as an alternative
solution.
--CUT--
public class IntegralValuedMutation<P> implements MutationPolicy<P> {
private final UniformRandomProvider provider;
public IntegralValuedMutation() {
provider = ThreadLocalRandomSource.current(RandomSource.DEFAULT);
//DEFAULT is a chosen source.
}
public IntegralValuedMutation(RandomSource rng) {
provider = ThreadLocalRandomSource.current(rng);
}
...
}
//Usages
MutationPolicy<Integer> policy = new IntegralValuedMutation(rng);
--CUT--
Option2 looks to be much simpler regarding implementation and I would vote
for the same if we decide to allow customization of RandomSource.
Thanks & Regards
--Avijit Basak
On Mon, 22 Nov 2021 at 19:28, Gilles Sadowski <[email protected]> wrote:
> Hello.
>
> Le lun. 22 nov. 2021 à 13:49, Avijit Basak <[email protected]> a
> écrit :
> >
> > Hi All
> >
> > I would like to request everyone to share their opinion regarding
> > use and customization of RNG functionality in the Genetic Algorithm
> > library.
> > In current design RNG functionality has been used internally by
> the
> > RandomProviderManager class. This class encapsulates a predefined
> instance
> > of RandomSource and utilizes the same for all random number generation
> > requirements. This makes the API cleaner and easy to use for users.
> > However, during the review an alternate thought has been proposed
> > related to customization of RandomSource by users. According to the new
> > proposal the users will be able to provide a RandomSource instance of
> their
> > choice to the crossover and mutation operators and other places like
> > ChromosomeRepresentationUtils. The drawback of this customization could
> be
> > increased complexity of the API.
>
> Please provide an usage example of both (showing that the alternative
> would actually increase the API complexity).
>
> Thanks,
> Gilles
>
> > We need to decide here whether we really need this kind of
> > customization by users and if yes the method of doing so. Here two
> options
> > have been proposed.
> > *Option1:*
> > ---CUT---
> > public interface MutationPolicy<P> {
> > Chromosome<P> mutate(Chromosome<P> original, double mutationRate);
> >
> > interface Factory<P> {
> > /**
> > * Creates an instance with a dedicated source of randomness.
> > *
> > * @param rng RNG algorithm.
> > * @param seed Seed.
> > * @return an instance that must <em>not</em> be shared among
> > threads.
> > */
> > MutationPolicy<P> create(RandomSource rng, Object seed);
> >
> > default MutationPolicy<P> create(RandomSource rng) {
> > return create(rng, null);
> > }
> > default MutationPolicy<P> create() {
> > return create(RandomSource.SPLIT_MIX_64);
> > }
> > }
> > }
> > ---CUT---
> >
> > *Option 2:*
> > Use of an optional constructor argument for all crossover and mutation
> > operators. Users will be providing a RandomSource instance of their
> choice
> > or use the default one configured while instantiating the operators.
> >
> > Thanks & Regards
> > -- Avijit Basak
>
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>
>
--
Avijit Basak
