Package org.apache.lucene.util.bkd

Class BKDRadixSelector

java.lang.Object

org.apache.lucene.util.bkd.BKDRadixSelector

public final class BKDRadixSelector
extends Object

Offline Radix selector for BKD tree.

NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	BKDRadixSelector.PathSlice	Sliced reference to points in an PointWriter.

Constructor Summary

Constructors

Constructor	Description
BKDRadixSelector(BKDConfig config, int maxPointsSortInHeap, Directory tempDir, String tempFileNamePrefix)	Sole constructor.

Method Summary

Modifier and Type	Method	Description
void	heapRadixSort(HeapPointWriter points, int from, int to, int dim, int commonPrefixLength)	Sort the heap writer by the specified dim.
byte[]	select(BKDRadixSelector.PathSlice points, BKDRadixSelector.PathSlice[] partitionSlices, long from, long to, long partitionPoint, int dim, int dimCommonPrefix)	It uses the provided points from the given from to the given to to populate the partitionSlices array holder (length > 1) with two path slices so the path slice at position 0 contains partition - from points where the value of the dim is lower or equal to the to -from points on the slice at position 1.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

BKDRadixSelector

public BKDRadixSelector(BKDConfig config,
                        int maxPointsSortInHeap,
                        Directory tempDir,
                        String tempFileNamePrefix)

Sole constructor.

Method Detail

select

public byte[] select(BKDRadixSelector.PathSlice points,
                     BKDRadixSelector.PathSlice[] partitionSlices,
                     long from,
                     long to,
                     long partitionPoint,
                     int dim,
                     int dimCommonPrefix)
              throws IOException

It uses the provided points from the given from to the given to to populate the partitionSlices array holder (length > 1) with two path slices so the path slice at position 0 contains partition - from points where the value of the dim is lower or equal to the to -from points on the slice at position 1.

The dimCommonPrefix provides a hint for the length of the common prefix length for the dim where are partitioning the points.

It return the value of the dim at the partition point.

If the provided points is wrapping an OfflinePointWriter, the writer is destroyed in the process to save disk space.

Throws:

IOException

heapRadixSort

public void heapRadixSort(HeapPointWriter points,
                          int from,
                          int to,
                          int dim,
                          int commonPrefixLength)

Sort the heap writer by the specified dim. It is used to sort the leaves of the tree