org.apache.lucene.facet.util
Class RandomSample.Algorithm

java.lang.Object
  extended by org.apache.lucene.facet.util.RandomSample.Algorithm
Enclosing class:
RandomSample

public static class RandomSample.Algorithm
extends Object

For specifying which sampling algorithm to use.


Field Summary
static RandomSample.Algorithm HASHING
          Specifies a Fibonacci-style hash algorithm (see Knuth, S&S), which generates a less systematically distributed subset of the sampled collection than the traversal method, but requires a bounded priority queue the size of the sample, and creates an object containing a sampled value and its hash, for every element in the full set.
static RandomSample.Algorithm TRAVERSAL
          Specifies a methodical traversal algorithm, which is guaranteed to span the collection at least once, and never to return duplicates.
 
Method Summary
 String toString()
          Prints this algorithm's name.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

TRAVERSAL

public static final RandomSample.Algorithm TRAVERSAL
Specifies a methodical traversal algorithm, which is guaranteed to span the collection at least once, and never to return duplicates. Faster than the hashing algorithm and uses much less space, but the randomness of the sample may be affected by systematic variations in the collection. Requires only an array for the sample, and visits only the number of elements in the sample set, not the full set.


HASHING

public static final RandomSample.Algorithm HASHING
Specifies a Fibonacci-style hash algorithm (see Knuth, S&S), which generates a less systematically distributed subset of the sampled collection than the traversal method, but requires a bounded priority queue the size of the sample, and creates an object containing a sampled value and its hash, for every element in the full set.

Method Detail

toString

public String toString()
Prints this algorithm's name.

Overrides:
toString in class Object


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