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