org.apache.sysds.runtime.compress

Class CompressionSettings

java.lang.Object

org.apache.sysds.runtime.compress.CompressionSettings

public class CompressionSettings
extends Object

Compression Settings class, used as a bundle of parameters inside the Compression framework. See CompressionSettingsBuilder for default non static parameters.

Field Summary

Fields

Modifier and Type	Field and Description
boolean	allowSharedDictionary Share DDC Dictionaries between ColGroups.
static int	BITMAP_BLOCK_SZ Size of the blocks used in a blocked bitmap representation.
double	coCodePercentage A Cocode parameter that differ in behavior based on compression method, in general it is a value that reflects aggressively likely coCoding is used.
PlanningCoCoder.PartitionerType	columnPartitioner The selected method for column partitioning used in CoCoding compressed columns
SampleEstimatorFactory.EstimationType	estimationType The sample type used for sampling
boolean	lossy True if lossy compression is enabled
int	maxColGroupCoCode The maximum number of columns CoCoded allowed
int	minimumSampleSize The minimum size of the sample extracted.
double	samplingRatio The sampling ratio used when choosing ColGroups.
int	seed If the seed is -1 then the system used system millisecond time and class hash for seeding.
boolean	skipList Boolean specifying if the OLE and RLE should construct skip to enable skipping large amounts of rows.
boolean	sortValuesByLength Sorting of values by physical length helps by 10-20%, especially for serial, while slight performance decrease for parallel incl multi-threaded, hence not applied for distributed operations (also because compression time + garbage collection increases)
boolean	transposed Transpose input matrix, to optimize access when extracting bitmaps.
String	transposeInput Boolean specifying which transpose setting is used, can be auto, true or false
EnumSet<AColGroup.CompressionType>	validCompressions Valid Compressions List, containing the ColGroup CompressionTypes that are allowed to be used for the compression Default is to always allow for Uncompromisable ColGroup.

Method Summary

Modifier and Type	Method and Description
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

BITMAP_BLOCK_SZ

public static final int BITMAP_BLOCK_SZ

Size of the blocks used in a blocked bitmap representation. Note it is exactly Character.MAX_VALUE. This is not Character max value + 1 because it breaks the offsets in cases with fully dense values.

See Also:

Constant Field Values

sortValuesByLength

public final boolean sortValuesByLength

Sorting of values by physical length helps by 10-20%, especially for serial, while slight performance decrease for parallel incl multi-threaded, hence not applied for distributed operations (also because compression time + garbage collection increases)

samplingRatio

public final double samplingRatio

The sampling ratio used when choosing ColGroups. Note that, default behavior is to use exact estimator if the number of elements is below 1000.

allowSharedDictionary

public final boolean allowSharedDictionary

Share DDC Dictionaries between ColGroups.

transposeInput

public final String transposeInput

Boolean specifying which transpose setting is used, can be auto, true or false

transposed

public boolean transposed

Transpose input matrix, to optimize access when extracting bitmaps. This setting is changed inside the script based on the transposeInput setting.

skipList

public final boolean skipList

Boolean specifying if the OLE and RLE should construct skip to enable skipping large amounts of rows. (Optimization)

seed

public final int seed

If the seed is -1 then the system used system millisecond time and class hash for seeding.

lossy

public final boolean lossy

True if lossy compression is enabled

columnPartitioner

public final PlanningCoCoder.PartitionerType columnPartitioner

The selected method for column partitioning used in CoCoding compressed columns

maxColGroupCoCode

public final int maxColGroupCoCode

The maximum number of columns CoCoded allowed

coCodePercentage

public final double coCodePercentage

A Cocode parameter that differ in behavior based on compression method, in general it is a value that reflects aggressively likely coCoding is used.

validCompressions

public final EnumSet<AColGroup.CompressionType> validCompressions

Valid Compressions List, containing the ColGroup CompressionTypes that are allowed to be used for the compression Default is to always allow for Uncompromisable ColGroup.

minimumSampleSize

public final int minimumSampleSize

The minimum size of the sample extracted.

estimationType

public final SampleEstimatorFactory.EstimationType estimationType

The sample type used for sampling

Method Detail

toString

public String toString()

Overrides:

toString in class Object