Package org.apache.sysds.runtime.compress.bitmap

Class BitmapEncoder

java.lang.Object

org.apache.sysds.runtime.compress.bitmap.BitmapEncoder

public class BitmapEncoder
extends Object

Static functions for extracting bitmaps from a MatrixBlock.

Constructor Summary

Constructors

Constructor	Description
BitmapEncoder()

Method Summary

Modifier and Type	Method	Description
static ABitmap	extractBitmap(int[] colIndices, MatrixBlock rawBlock, boolean transposed, int estimatedNumberOfUniques, boolean sortedEntries)	Generate uncompressed bitmaps for a set of columns in an uncompressed matrix block.

Methods inherited from class java.lang.Object

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

Constructor Detail

BitmapEncoder

public BitmapEncoder()

Method Detail

extractBitmap

public static ABitmap extractBitmap(int[] colIndices,
                                    MatrixBlock rawBlock,
                                    boolean transposed,
                                    int estimatedNumberOfUniques,
                                    boolean sortedEntries)

Generate uncompressed bitmaps for a set of columns in an uncompressed matrix block. if the rawBlock is transposed and sparse it should be guaranteed that the rows specified are not empty, aka all zero.

Parameters:

colIndices - Indexes (within the block) of the columns to extract

rawBlock - An uncompressed matrix block; can be dense, sparse, empty, or null (not Compressed!)

transposed - Boolean specifying if the rawBlock was transposed.

estimatedNumberOfUniques - The number of estimated uniques inside this group. Used to allocated the HashMaps.

sortedEntries - Boolean specifying if the entries should be sorted based on frequency of tuples

Returns:

Uncompressed bitmap representation of the columns specified