1 /* 2 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 /* 25 * @test 26 * @bug 8214761 27 * @summary When combining two DoubleSummaryStatistics, the compensation 28 * has to be subtracted. 29 */ 30 31 import java.util.DoubleSummaryStatistics; 32 33 public class NegativeCompensation { 34 static final double VAL = 1.000000001; 35 static final int LOG_ITER = 21; 36 37 public static void main(String[] args) { 38 DoubleSummaryStatistics stat0 = new DoubleSummaryStatistics(); 39 DoubleSummaryStatistics stat1 = new DoubleSummaryStatistics(); 40 DoubleSummaryStatistics stat2 = new DoubleSummaryStatistics(); 41 42 stat1.accept(VAL); 43 stat1.accept(VAL); 44 stat2.accept(VAL); 45 stat2.accept(VAL); 46 stat2.accept(VAL); 47 48 for (int i = 0; i < LOG_ITER; ++i) { 49 stat1.combine(stat2); 50 stat2.combine(stat1); 51 } 52 53 System.out.println("count: " + stat2.getCount()); 54 for (long i = 0, iend = stat2.getCount(); i < iend; ++i) { 55 stat0.accept(VAL); 56 } 57 58 double absErr = Math.abs(stat0.getSum() - stat2.getSum()); 59 System.out.println("serial sum: " + stat0.getSum()); 60 System.out.println("combined sum: " + stat2.getSum()); 61 System.out.println("abs error: " + absErr); 62 if (absErr > 0.00000001) { 63 throw new RuntimeException("Absolute error is too big: " + absErr); 64 } 65 } 66 }