hex.createframe

Class CreateFrameColumnMaker

java.lang.Object

water.Iced<CreateFrameColumnMaker>

hex.createframe.CreateFrameColumnMaker

All Implemented Interfaces:

java.io.Externalizable, java.io.Serializable, java.lang.Cloneable, Freezable<CreateFrameColumnMaker>

Direct Known Subclasses:

BinaryColumnCfcm, CategoricalColumnCfcm, IntegerColumnCfcm, RealColumnCfcm, StringColumnCfcm, TimeColumnCfcm

public abstract class CreateFrameColumnMaker
extends Iced<CreateFrameColumnMaker>

Base class for all "column makers" used by the CreateFrameExecutor to construct the frame. Typically a subclass would be creating just a single column having a certain type, name and the distribution of values. However it is also possible to create a subclass that constructs 0 columns (i.e. just modifies the previously constructed ones), or one that creates more than 1 columns at once.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected int	index

Constructor Summary

Constructors

Constructor and Description
CreateFrameColumnMaker()

Method Summary

Modifier and Type	Method and Description
float	byteSizePerRow() Estimated byte size of a single row created by this column maker.
java.lang.String[][]	columnDomains() Domains for categorical columns being created (if any).
abstract java.lang.String[]	columnNames() Names of the columns produces by this column maker.
abstract byte[]	columnTypes() Types of the columns produced by the column maker.
abstract void	exec(int nrows, NewChunk[] ncs, java.util.Random rng) Implement this method in a subclass to actually build the columns.
int	numColumns() Number of columns described by this column maker.
void	setIndex(int i) Index of the first column that this column maker will be creating.
int	workAmount() Relative amount of work this column maker performs to fill a chunk.

Methods inherited from class water.Iced

asBytes, clone, copyOver, frozenType, read, readExternal, readJSON, reloadFromBytes, toJsonBytes, toJsonString, write, writeExternal, writeJSON

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

index

protected int index

Constructor Detail

CreateFrameColumnMaker

public CreateFrameColumnMaker()

Method Detail

exec

public abstract void exec(int nrows,
                          NewChunk[] ncs,
                          java.util.Random rng)

Implement this method in a subclass to actually build the columns.

Parameters:

nrows - Number of rows in the current chunk. If method is creating new columns, then it is supposed to add this many rows.

ncs - The `NewChunk`s array passed down from the `map()` method in `MRTask`. A subclass is expected to know which NewChunks it is allowed to touch, usually with the help of the index variable.

rng - Random number generator that the subclass may use to fill the columns randomly. Do NOT use any other random generator as doing so will break the reproducibility promise of the CreateFrame service.

numColumns

public int numColumns()

Number of columns described by this column maker. Usually this is 1, however it is possible that some tasks may create either 0 columns (i.e. they only modify existing ones), or create several columns at once (for example if you're trying to create one-hot encoded categorical).

columnTypes

public abstract byte[] columnTypes()

Types of the columns produced by the column maker. The returned array should have exactly the same number of elements as given by numColumns().

columnNames

public abstract java.lang.String[] columnNames()

Names of the columns produces by this column maker. Should also have the same number of elements as given by numColumns().

columnDomains

public java.lang.String[][] columnDomains()

Domains for categorical columns being created (if any).

setIndex

public void setIndex(int i)

Index of the first column that this column maker will be creating. This method is used by the executor, and the index variable it sets can be used to determine which columns in the ncs array to fill during the exec(int, NewChunk[], Random) step.

byteSizePerRow

public float byteSizePerRow()

Estimated byte size of a single row created by this column maker. This estimate is later used to determine optimal chunk size for the produced frame, thus it doesn't have to be very precise.

workAmount

public int workAmount()

Relative amount of work this column maker performs to fill a chunk. The base amount of 100 corresponds to a method that draws a single random number per row and then uses simple arithmetic before adding a value to the NewChunk.

The output will be used to inform te Job about progress being made. It needn't be very precise.