it.uniroma2.sag.kelp.kernel.standard.PolynomialKernel.java Source code

Introduction

Here is the source code for it.uniroma2.sag.kelp.kernel.standard.PolynomialKernel.java

Source

/*
 * Copyright 2014 Simone Filice and Giuseppe Castellucci and Danilo Croce and Roberto Basili
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package it.uniroma2.sag.kelp.kernel.standard;

/**
 * Polynomial Kernel: given a kernel K, the polynomial formula Kp is
 * 
 * \(Kp(x,y)=(a*K(x,y)+b)^d\)
 * 
 * @author Simone Filice
 */
import it.uniroma2.sag.kelp.data.example.Example;
import it.uniroma2.sag.kelp.kernel.Kernel;
import it.uniroma2.sag.kelp.kernel.KernelComposition;

import com.fasterxml.jackson.annotation.JsonTypeName;

@JsonTypeName("poly")
public class PolynomialKernel extends KernelComposition {

    private float degree;
    private float a = 1f;
    private float b = 0f;

    public PolynomialKernel(float degree, float a, float b, Kernel inputSpace) {
        this.baseKernel = inputSpace;
        this.degree = degree;
        this.a = a;
        this.b = b;

    }

    public PolynomialKernel(float degree, Kernel inputSpace) {
        this(degree, 1, 0, inputSpace);
    }

    public PolynomialKernel() {

    }

    @Override
    protected float kernelComputation(Example exA, Example exB) {
        float dotProduct = this.baseKernel.innerProduct(exA, exB);

        if (this.degree == (int) this.degree) {
            return it.uniroma2.sag.kelp.utils.Math.pow((this.a * dotProduct + this.b), (int) degree);
        }
        return (float) Math.pow((this.a * dotProduct + this.b), degree);
    }

    /**
     * @return the degree
     */
    public float getDegree() {
        return degree;
    }

    /**
     * @param degree the degree to set
     */
    public void setDegree(float degree) {
        this.degree = degree;
    }

    /**
     * @return the a
     */
    public float getA() {
        return a;
    }

    /**
     * @param a the a to set
     */
    public void setA(float a) {
        this.a = a;
    }

    /**
     * @return the b
     */
    public float getB() {
        return b;
    }

    /**
     * @param b the b to set
     */
    public void setB(float b) {
        this.b = b;
    }

}