[jira] [Created] (RNG-102) SharedStateSampler interface

["Alex D Herbert (JIRA)" <ji...@apache.org>]

Alex D Herbert created RNG-102:
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             Summary: SharedStateSampler interface
                 Key: RNG-102
                 URL: https://issues.apache.org/jira/browse/RNG-102
             Project: Commons RNG
          Issue Type: New Feature
          Components: sampling
    Affects Versions: 1.3
            Reporter: Alex D Herbert


Nearly all the samplers in the library compute data during construction that is immutable. In most cases the data is small in size but could be large (e.g. a discrete probability sampler with a stored cumulative probability table). To build another sampler with the same parameters will have to re-compute this state. The only difference between the two samplers is the random generator.

Reusing this state to create a duplicate generator is an advantage for lower construction cost and will save memory. This can be done using a generic interface:
{code:java}
public interface SharedStateSampler<R> {
   R withUniformRandomProvider(UniformRandomProvider rng);
}
{code}
R is expected to be a sampler of some type, e.g.
{code:java}
public class CollectionSampler<T>
   implements SharedStateSampler<CollectionSampler<T>> {
   // ...
   public CollectionSampler<T>
           withUniformRandomProvider(UniformRandomProvider rng) {
       return /* new instance that shares the immutable state */;
   }
}
{code}

An example application would be to create a single sampler to be duplicated across threads for parallel computation using a unique RNG per thread.



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