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Java example source code file (BaseMultivariateOptimizer.java)

This example Java source code file (BaseMultivariateOptimizer.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

basemultivariateoptimizer, baseoptimizer, initialguess, numberistoolargeexception, numberistoosmallexception, optimizationdata, override, pair, simplebounds

The BaseMultivariateOptimizer.java Java example source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.commons.math3.optim;

import org.apache.commons.math3.exception.DimensionMismatchException;
import org.apache.commons.math3.exception.NumberIsTooSmallException;
import org.apache.commons.math3.exception.NumberIsTooLargeException;

/**
 * Base class for implementing optimizers for multivariate functions.
 * It contains the boiler-plate code for initial guess and bounds
 * specifications.
 * <em>It is not a "user" class.
 *
 * @param <PAIR> Type of the point/value pair returned by the optimization
 * algorithm.
 *
 * @since 3.1
 */
public abstract class BaseMultivariateOptimizer<PAIR>
    extends BaseOptimizer<PAIR> {
    /** Initial guess. */
    private double[] start;
    /** Lower bounds. */
    private double[] lowerBound;
    /** Upper bounds. */
    private double[] upperBound;

    /**
     * @param checker Convergence checker.
     */
    protected BaseMultivariateOptimizer(ConvergenceChecker<PAIR> checker) {
        super(checker);
    }

    /**
     * {@inheritDoc}
     *
     * @param optData Optimization data. In addition to those documented in
     * {@link BaseOptimizer#parseOptimizationData(OptimizationData[]) BaseOptimizer},
     * this method will register the following data:
     * <ul>
     *  <li>{@link InitialGuess}
     *  <li>{@link SimpleBounds}
     * </ul>
     * @return {@inheritDoc}
     */
    @Override
    public PAIR optimize(OptimizationData... optData) {
        // Perform optimization.
        return super.optimize(optData);
    }

    /**
     * Scans the list of (required and optional) optimization data that
     * characterize the problem.
     *
     * @param optData Optimization data. The following data will be looked for:
     * <ul>
     *  <li>{@link InitialGuess}
     *  <li>{@link SimpleBounds}
     * </ul>
     */
    @Override
    protected void parseOptimizationData(OptimizationData... optData) {
        // Allow base class to register its own data.
        super.parseOptimizationData(optData);

        // The existing values (as set by the previous call) are reused if
        // not provided in the argument list.
        for (OptimizationData data : optData) {
            if (data instanceof InitialGuess) {
                start = ((InitialGuess) data).getInitialGuess();
                continue;
            }
            if (data instanceof SimpleBounds) {
                final SimpleBounds bounds = (SimpleBounds) data;
                lowerBound = bounds.getLower();
                upperBound = bounds.getUpper();
                continue;
            }
        }

        // Check input consistency.
        checkParameters();
    }

    /**
     * Gets the initial guess.
     *
     * @return the initial guess, or {@code null} if not set.
     */
    public double[] getStartPoint() {
        return start == null ? null : start.clone();
    }
    /**
     * @return the lower bounds, or {@code null} if not set.
     */
    public double[] getLowerBound() {
        return lowerBound == null ? null : lowerBound.clone();
    }
    /**
     * @return the upper bounds, or {@code null} if not set.
     */
    public double[] getUpperBound() {
        return upperBound == null ? null : upperBound.clone();
    }

    /**
     * Check parameters consistency.
     */
    private void checkParameters() {
        if (start != null) {
            final int dim = start.length;
            if (lowerBound != null) {
                if (lowerBound.length != dim) {
                    throw new DimensionMismatchException(lowerBound.length, dim);
                }
                for (int i = 0; i < dim; i++) {
                    final double v = start[i];
                    final double lo = lowerBound[i];
                    if (v < lo) {
                        throw new NumberIsTooSmallException(v, lo, true);
                    }
                }
            }
            if (upperBound != null) {
                if (upperBound.length != dim) {
                    throw new DimensionMismatchException(upperBound.length, dim);
                }
                for (int i = 0; i < dim; i++) {
                    final double v = start[i];
                    final double hi = upperBound[i];
                    if (v > hi) {
                        throw new NumberIsTooLargeException(v, hi, true);
                    }
                }
            }
        }
    }
}

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