water.util

Class ModelUtils

java.lang.Object

water.util.ModelUtils

public class ModelUtils
extends java.lang.Object

Shared static code to support modeling, prediction, and scoring.

Used by interpreted models as well as by generated model code.

WARNING: The class should have no other H2O dependencies since it is provided for generated code as h2o-model.jar which contains only a few files.

Constructor Summary

Constructors

Constructor and Description
ModelUtils()

Method Summary

Methods

Modifier and Type	Method and Description
static double[]	correctProbabilities(double[] scored, double[] priorClassDist, double[] modelClassDist) Correct a given list of class probabilities produced as a prediction by a model back to prior class distribution
static int	getPrediction(double[] preds)
static int[]	sampleOOBRows(int nrows, float rate, java.util.Random sampler) Sample out-of-bag rows with given rate with help of given sampler.
static int[]	sampleOOBRows(int nrows, float rate, java.util.Random sampler, int[] oob) In-situ version of sampleOOBRows(int, float, Random).

Methods inherited from class java.lang.Object

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

Constructor Detail

ModelUtils

public ModelUtils()

Method Detail

getPrediction

public static int getPrediction(double[] preds)

correctProbabilities

public static double[] correctProbabilities(double[] scored,
                            double[] priorClassDist,
                            double[] modelClassDist)

Correct a given list of class probabilities produced as a prediction by a model back to prior class distribution

The implementation is based on Eq. (27) in the paper.

Parameters:

scored - list of class probabilities beginning at index 1

priorClassDist - original class distribution

modelClassDist - class distribution used for model building (e.g., data was oversampled)

Returns:

corrected list of probabilities

sampleOOBRows

public static int[] sampleOOBRows(int nrows,
                  float rate,
                  java.util.Random sampler)

Sample out-of-bag rows with given rate with help of given sampler. It returns array of sampled rows. The first element of array contains a number of sampled rows. The returned array can be larger than number of returned sampled elements.

Parameters:

nrows - number of rows to sample from.

rate - sampling rate

sampler - random "dice"

Returns:

an array contains numbers of sampled rows. The first element holds a number of sampled rows. The array length can be greater than number of sampled rows.

sampleOOBRows

public static int[] sampleOOBRows(int nrows,
                  float rate,
                  java.util.Random sampler,
                  int[] oob)

In-situ version of sampleOOBRows(int, float, Random).

Parameters:

oob - an initial array to hold sampled rows. Can be internally reallocated.

Returns:

an array containing sampled rows.

See Also:

sampleOOBRows(int, float, Random)