Package org.apache.sysds.runtime.compress.cost

Class ACostEstimate

java.lang.Object

org.apache.sysds.runtime.compress.cost.ACostEstimate

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

ComputationCostEstimator, DistinctCostEstimator, HybridCostEstimator, MemoryCostEstimator

public abstract class ACostEstimate
extends Object
implements Serializable

A cost estimator interface. It is used to estimate the cost at different stages of compression, and used to compare to uncompressed.

See Also:

Serialized Form

Method Summary

Modifier and Type	Method	Description
double	getCost(Collection<AColGroup> cgs, int nRows)	Get the cost of a collection of column groups.
abstract double	getCost(AColGroup cg, int nRows)	Get the cost of a compressed columnGroup.
double	getCost(CompressedMatrixBlock cmb)	Get cost of a compressed matrix block
double	getCost(CompressedSizeInfo i)	Get cost of an entire compression plan
double	getCost(CompressedSizeInfoColGroup g)	Get cost of a single column group estimate.
abstract double	getCost(MatrixBlock mb)	Get the cost of a matrix block.
abstract boolean	shouldSparsify()	Ask the cost estimator if it is a good idea to try to sparsify a column group.
String	toString()

Methods inherited from class java.lang.Object

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

Method Detail

getCost

public double getCost(Collection<AColGroup> cgs,
                      int nRows)

Get the cost of a collection of column groups.

Parameters:

cgs - A collection of column groups

nRows - The number of rows in the column group

Returns:

The summed cost of the groups

getCost

public final double getCost(CompressedSizeInfoColGroup g)

Get cost of a single column group estimate. If the input is null the cost is positive infinity indicating that it is impossible to compress the null case. If the instruction does not care about the inter column group cost, such as in memory cost or in computation cost of right or left matrix multiplication we simply estimate the cost of individual column groups.

Parameters:

g - Column group to estimate the cost of

Returns:

The Cost of this column group

getCost

public double getCost(CompressedSizeInfo i)

Get cost of an entire compression plan

Parameters:

i - The compression plan to get the cost of

Returns:

The cost

getCost

public double getCost(CompressedMatrixBlock cmb)

Get cost of a compressed matrix block

Parameters:

cmb - The compressed matrix block

Returns:

The cost

getCost

public abstract double getCost(MatrixBlock mb)

Get the cost of a matrix block.

Parameters:

mb - A MatrixBlock

Returns:

The cost subject to the internal cost functions

getCost

public abstract double getCost(AColGroup cg,
                               int nRows)

Get the cost of a compressed columnGroup.

Parameters:

cg - A ColumnGroup

nRows - The number of rows in the column group

Returns:

The cost subject to the internal cost functions

shouldSparsify

public abstract boolean shouldSparsify()

Ask the cost estimator if it is a good idea to try to sparsify a column group. It is the same as asking if it is a good idea to make FOR on top of the column group.

Returns:

true if yes

toString

public String toString()

Overrides:

toString in class Object