/*
* File: AbstractDiscriminantBinaryCategorizer.java
* Authors: Justin Basilico
* Company: Sandia National Laboratories
* Project: Cognitive Foundry Learning Core
*
* Copyright February 03, 2011, Sandia Corporation.
* Under the terms of Contract DE-AC04-94AL85000, there is a non-exclusive
* license for use of this work by or on behalf of the U.S. Government. Export
* of this program may require a license from the United States Government.
*/
package gov.sandia.cognition.learning.function.categorization;
import gov.sandia.cognition.learning.data.ValueDiscriminantPair;
import gov.sandia.cognition.learning.data.DefaultWeightedValueDiscriminant;
/**
* An abstract implementation of the {@code DiscriminantBinaryCategorizer}
* interface. Provides implementations of the evaluate and
* evaluateWithDiscriminant that call evaluateAsDouble and uses the sign as
* the category and the magnitude as the discriminant.
*
* @param <InputType>
* The type of the input the categorizer can use.
* @author Justin Basilico
* @since 3.1
*/
public abstract class AbstractDiscriminantBinaryCategorizer<InputType>
extends AbstractBinaryCategorizer<InputType>
implements DiscriminantBinaryCategorizer<InputType>
{
/**
* Creates a new {@code AbstractDiscriminantBinaryCategorizer}.
*/
public AbstractDiscriminantBinaryCategorizer()
{
super();
}
@Override
public Boolean evaluate(
final InputType input)
{
// The sign of the double evaluation is the category.
return this.evaluateAsDouble(input) >= 0.0;
}
@Override
public ValueDiscriminantPair<Boolean, Double> evaluateWithDiscriminant(
final InputType input)
{
// Evaluate the input as a double whose sign is the category.
final double value = this.evaluateAsDouble(input);
final boolean category = value >= 0.0;
// The discriminant needs to be larger for a better match, even in
// the case of the false category, which requires doing an absolute
// value to the sign.
final double discriminant = category ? value : -value;
return DefaultWeightedValueDiscriminant.create(category, discriminant);
}
}