Hi.
2020-03-18 15:10 UTC+01:00, chentao...@qq.com <chentao...@qq.com>:
> Hi,
> I have created a PR to show my aim:
> https://github.com/apache/commons-math/pull/126/files
Am I correct that the implementations of "ClustersPointExtractor"
modify the argument of the "extract" method?
If so, that seems quite unsafe. I would not expect this behaviour
in a public API.
Unless I missed some point, I'd ask again that the API be reviewed
*before* implementing several features (such as those "extractors")
on top of something that does not look right.
Best regards,
Gilles
>
>>Hello.
>>
>>Le mer. 11 mars 2020 à 07:28, chentao...@qq.com <chentao...@qq.com> a écrit
>> :
>>>
>>> Hi all,
>>> The "EmptyClusterStrategy" in KMeansPlusPlusClusterer can be reused
>>> MiniBatchKMeansClusterer and other cluster altorithm.
>>> So I think the "EmptyClusterStrategy" should move out from
>>> KMeansPlusPlusClusterer(JIRA issue #MATH-1525).
>>> I am not sure if my design is good or not.
>>
>>I can't say either; please provide more context/explanation
>>about the excerpts below.
>>
>>> I think here should be a interface:
>>>
>>> Solution 1: Explicit indicate the usage by class name and function name.
>>> ```java
>>> @FunctionalInterface
>>> public interface ClusterBreeder {
>>> <T extends Clusterable> T newCenterPoint((final
>>> Collection<CentroidCluster<T extends Clusterable>> clusters);
>>> }
>>
>>What is a "Breeder"?
>>This seems to further complicates the matter; what is a "center" (if there
>>can be old and new ones).
>
> I mean a method to create a new Cluster from exists clusters.
>
>>
>>Regards,
>>Gilles
>>
>>> ...
>>> // Implementations
>>> public LargestVarianceClusterPointBreeder implements ClusterBreeder{...}
>>> public MostPopularClusterPointBreeder implements ClusterBreeder{...}
>>> public FarthestPointBreeder implements ClusterBreeder{...}
>>> ...
>>> // Usage
>>> // KMeansPlusPlusClusterer.java
>>> public class KMeansPlusPlusClusterer<T extends Clusterable> extends
>>> Clusterer<T> {
>>> ...
>>> private final ClusterBreeder clusterBreeder;
>>> public KMeansPlusPlusClusterer(final int k, final int maxIterations,
>>> final DistanceMeasure measure,
>>> final UniformRandomProvider random,
>>> final ClusterBreeder clusterBreeder) {
>>> ...
>>> this.clusterBreeder=clusterBreeder;
>>> }
>>> ...
>>> public List<CentroidCluster<T>> cluster(final Collection<T> points) {
>>> ...
>>> if (cluster.getPoints().isEmpty()) {
>>> if (clusterBreeder == null) {
>>> throw new
>>> ConvergenceException(LocalizedFormats.EMPTY_CLUSTER_IN_K_MEANS);
>>> } else {
>>> newCenter = clusterBreeder.newCenterPoint(clusters);
>>> }
>>> }
>>> ...
>>> }
>>> }
>>> ```
>>>
>>> Solution2: Declare a more generic interface:
>>> ```java
>>> @FunctionalInterface
>>> public interface ClustersPointFinder {
>>> <T extends Clusterable> T find((final Collection<CentroidCluster<T
>>> extends Clusterable>> clusters);
>>> }
>>>
>>> ...
>>> // Implementations
>>> public LargestVarianceClusterPointFinder implements ClustersPointFinder
>>> {...}
>>> public MostPopularClusterPointFinder implements ClustersPointFinder {...}
>>> public FarthestPointFinder implements ClustersPointFinder {...}
>>> ```
>>>
>>> Thanks,
>>> -CT
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