# Package org.apache.sysds.runtime.compress.colgroup

Class Summary
AColGroup: Abstract Class that is the lowest class type for the Compression framework.
ColGroupCompressed: Base class for column groups encoded Encoded in a compressed manner.
ColGroupConst
ColGroupDDC: Class to encapsulate information about a column group that is encoded with dense dictionary encoding (DDC).
ColGroupEmpty
ColGroupFactory: Factory pattern for constructing ColGroups.
ColGroupIO: This has the IO responsibility of ColGroups, such that it enables to read and write ColGroups to and from a DataInput and DataOutput
ColGroupOffset: Base class for column groups encoded with various types of bitmap encoding.
ColGroupOLE: Class to encapsulate information about a column group that is encoded with simple lists of offsets for each set of distinct values.
ColGroupRLE: A group of columns compressed with a single run-length encoded bitmap.
ColGroupSDC: Column group that sparsely encodes the dictionary values.
ColGroupSDCSingle: Column group that sparsely encodes the dictionary values.
ColGroupSDCSingleZeros: Column group that sparsely encodes the dictionary values.
ColGroupSDCZeros: Column group that sparsely encodes the dictionary values.
ColGroupSizes
ColGroupUncompressed: Column group type for columns that are stored as dense arrays of doubles.
ColGroupValue: Base class for column groups encoded with value dictionary.

Enum Summary
AColGroup.CompressionType: Public super types of compression ColGroups supported