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

- Class Summary
  Class | Description
  --- | ---
  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
  Enum | Description
  --- | ---
  AColGroup.CompressionType | Public super types of compression ColGroups supported

Copyright © 2021 The Apache Software Foundation. All rights reserved.