001/* ===========================================================
002 * Orson Charts : a 3D chart library for the Java(tm) platform
003 * ===========================================================
004 * 
005 * (C)opyright 2013-2022, by David Gilbert.  All rights reserved.
006 * 
007 * https://github.com/jfree/orson-charts
008 * 
009 * This program is free software: you can redistribute it and/or modify
010 * it under the terms of the GNU General Public License as published by
011 * the Free Software Foundation, either version 3 of the License, or
012 * (at your option) any later version.
013 *
014 * This program is distributed in the hope that it will be useful,
015 * but WITHOUT ANY WARRANTY; without even the implied warranty of
016 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
017 * GNU General Public License for more details.
018 *
019 * You should have received a copy of the GNU General Public License
020 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
021 * 
022 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
023 * Other names may be trademarks of their respective owners.]
024 * 
025 * If you do not wish to be bound by the terms of the GPL, an alternative
026 * commercial license can be purchased.  For details, please see visit the
027 * Orson Charts home page:
028 * 
029 * http://www.object-refinery.com/orsoncharts/index.html
030 * 
031 */
032
033package org.jfree.chart3d.data.function;
034
035import org.jfree.chart3d.data.Range;
036import org.jfree.chart3d.internal.Args;
037
038/**
039 * Utility methods related to {@link Function3D}.
040 * 
041 * @since 1.1
042 */
043public class Function3DUtils {
044    
045    private Function3DUtils() {
046        // no need to instantiate this
047    }
048    
049    /**
050     * Returns the range of y-values in the function by sampling.
051     * 
052     * @param f  the function ({@code null} not permitted).
053     * @param xRange  the x-range to sample ({@code null} not permitted).
054     * @param zRange  the z-range to sample ({@code null} not permitted).
055     * @param xSamples  the number of x-samples (must be at least 2).
056     * @param zSamples  the number of z-samples (must be at least 2).
057     * @param ignoreNaN  if {@code true}, any {@code NaN} values will
058     *     be ignored.
059     * 
060     * @return The range ({@code null} in the case that the function 
061     *     returns no valid values). 
062     */
063    public static Range findYRange(Function3D f, Range xRange, Range zRange, 
064            int xSamples, int zSamples, boolean ignoreNaN) {
065        Args.nullNotPermitted(f, "f");
066        Args.nullNotPermitted(xRange, "xRange");
067        Args.nullNotPermitted(zRange, "zRange");
068        double min = Double.POSITIVE_INFINITY;
069        double max = Double.NEGATIVE_INFINITY;
070        for (int xIndex = 0; xIndex <= xSamples - 1; xIndex++) {
071            double fracX = xIndex / (xSamples - 1.0);
072            double x = xRange.value(fracX);
073            for (int zIndex = 0; zIndex <= zSamples - 1; zIndex++) {
074                double fracZ = zIndex / (zSamples - 1.0);
075                double z = zRange.value(fracZ);
076                double y = f.getValue(x, z);
077                if (Double.isNaN(y) && ignoreNaN) {
078                    continue;
079                }
080                min = Math.min(y, min);
081                max = Math.max(y, max);
082            }
083        }
084        if (min <= max) {
085            return new Range(min, max);
086        }
087        return null;
088    }
089}