SearchInterval.java

/*
 * 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
 *
 *      https://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.
 */

/*
 * This is not the original file distributed by the Apache Software Foundation
 * It has been modified by the Hipparchus project
 */
package org.hipparchus.optim.univariate;

import org.hipparchus.exception.LocalizedCoreFormats;
import org.hipparchus.exception.MathIllegalArgumentException;
import org.hipparchus.optim.OptimizationData;
import org.hipparchus.util.MathUtils;

/**
 * Search interval and (optional) start value.
 * <br>
 * Immutable class.
 *
 */
public class SearchInterval implements OptimizationData {
    /** Lower bound. */
    private final double lower;
    /** Upper bound. */
    private final double upper;
    /** Start value. */
    private final double start;

    /** Simple constructor.
     * @param lo Lower bound.
     * @param hi Upper bound.
     * @param init Start value.
     * @throws MathIllegalArgumentException if {@code lo >= hi}.
     * @throws MathIllegalArgumentException if {@code init < lo} or {@code init > hi}.
     */
    public SearchInterval(double lo,
                          double hi,
                          double init) {
        if (lo >= hi) {
            throw new MathIllegalArgumentException(LocalizedCoreFormats.NUMBER_TOO_LARGE_BOUND_EXCLUDED,
                                                   lo, hi);
        }

        MathUtils.checkRangeInclusive(init, lo, hi);

        lower = lo;
        upper = hi;
        start = init;
    }

    /** Simple constructor.
     * @param lo Lower bound.
     * @param hi Upper bound.
     * @throws MathIllegalArgumentException if {@code lo >= hi}.
     */
    public SearchInterval(double lo,
                          double hi) {
        this(lo, hi, 0.5 * (lo + hi));
    }

    /**
     * Gets the lower bound.
     *
     * @return the lower bound.
     */
    public double getMin() {
        return lower;
    }
    /**
     * Gets the upper bound.
     *
     * @return the upper bound.
     */
    public double getMax() {
        return upper;
    }
    /**
     * Gets the start value.
     *
     * @return the start value.
     */
    public double getStartValue() {
        return start;
    }
}