# Uses of Class
org.apache.sysds.runtime.compress.colgroup.APreAgg

Packages that use APreAgg
Package
Description
org.apache.sysds.runtime.compress.colgroup

## Uses of APreAgg in org.apache.sysds.runtime.compress.colgroup

Subclasses of APreAgg in org.apache.sysds.runtime.compress.colgroup
Modifier and Type
Class
Description
`class`
`AColGroupOffset`
Base class for column groups encoded with various types of bitmap encoding.
`class`
`ASDCZero`
`class`
`ColGroupDDC`
Class to encapsulate information about a column group that is encoded with dense dictionary encoding (DDC).
`class`
`ColGroupDDCLZW`
Class to encapsulate information about a column group that is encoded with dense dictionary encoding (DDC) whose mapping vector is additionally lzw compressed.
`class`
`ColGroupDeltaDDC`
Class to encapsulate information about a column group that is first delta encoded then encoded with dense dictionary encoding (DeltaDDC).
`class`
`ColGroupOLE`
Class to encapsulate information about a column group that is encoded with simple lists of offsets for each set of distinct values.
`class`
`ColGroupRLE`
A group of columns compressed with a single run-length encoded bitmap.
`class`
`ColGroupSDCSingleZeros`
Column group that sparsely encodes the dictionary values.
`class`
`ColGroupSDCZeros`
Column group that sparsely encodes the dictionary values.
Methods in org.apache.sysds.runtime.compress.colgroup with parameters of type APreAgg
Modifier and Type
Method
Description
`final IDictionary`
APreAgg.`preAggregateThatIndexStructure(APreAgg that)`
Pre aggregate into a dictionary.