de.termininistic.serein.examples.benchmarks.functions.unimodal.PermFunction.java Source code

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Here is the source code for de.termininistic.serein.examples.benchmarks.functions.unimodal.PermFunction.java

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/**
 * Copyright (C) 2015 Tobias Uhlig (tobias.uhlig@unibw.de)
 *
 * 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 de.termininistic.serein.examples.benchmarks.functions.unimodal;

import org.apache.commons.math3.linear.ArrayRealVector;
import org.apache.commons.math3.linear.RealVector;

import de.termininistic.serein.examples.benchmarks.functions.BenchmarkFunction;
import de.termininistic.serein.examples.benchmarks.functions.Domain;

public class PermFunction implements BenchmarkFunction {
    public final static Domain DEFAULT_DOMAIN = new Domain(-10, 10);
    public final static double DEFAULT_BETA = 10.0;
    private final Domain domain;
    private double beta;

    public PermFunction() {
        this(DEFAULT_BETA, DEFAULT_DOMAIN);
    }

    public PermFunction(double beta, Domain domain) {
        this.domain = domain;
        this.beta = beta;
    }

    @Override
    public Domain getDomain() {
        return domain;
    }

    @Override
    public RealVector getOptimum(int dimension) {
        double[] optimum = new double[dimension];
        for (int i = 0; i < dimension; i++) {
            optimum[i] = 1 / (i + 1);
        }
        return new ArrayRealVector(optimum);
    }

    @Override
    public double map(RealVector v) {
        double sum = 0.0;
        double[] x = v.toArray();
        for (int i = 0; i < x.length; i++) {
            double innerSum = 0.0;
            for (int j = 0; j < x.length; j++) {
                innerSum += (j + 1 + beta) * (Math.pow(x[j], i + 1) - 1 / Math.pow(j + 1, i + 1));
            }
            sum += innerSum * innerSum;
        }
        return sum;
    }

}