aoqi@0: /*
aoqi@0:  * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  *
aoqi@0:  */
aoqi@0: 
aoqi@0: /*
aoqi@0:  * Micro-benchmark for Math.pow() and Math.exp()
aoqi@0:  */
aoqi@0: 
aoqi@0: import java.util.*;
aoqi@0: 
aoqi@0: public class Test7177917 {
aoqi@0: 
aoqi@0:   static double d;
aoqi@0: 
aoqi@0:   static Random r = new Random(0);
aoqi@0: 
aoqi@0:   static long  m_pow(double[][] values) {
aoqi@0:     double res = 0;
aoqi@0:     long start = System.nanoTime();
aoqi@0:     for (int i = 0; i < values.length; i++) {
aoqi@0:       res += Math.pow(values[i][0], values[i][1]);
aoqi@0:     }
aoqi@0:     long stop = System.nanoTime();
aoqi@0:     d = res;
aoqi@0:     return (stop - start) / 1000;
aoqi@0:   }
aoqi@0: 
aoqi@0:   static long  m_exp(double[] values) {
aoqi@0:     double res = 0;
aoqi@0:     long start = System.nanoTime();
aoqi@0:     for (int i = 0; i < values.length; i++) {
aoqi@0:       res += Math.exp(values[i]);
aoqi@0:     }
aoqi@0:     long stop = System.nanoTime();
aoqi@0:     d = res;
aoqi@0:     return (stop - start) / 1000;
aoqi@0:   }
aoqi@0: 
aoqi@0:   static double[][] pow_values(int nb) {
aoqi@0:     double[][] res = new double[nb][2];
aoqi@0:     for (int i = 0; i < nb; i++) {
aoqi@0:       double ylogx = (1 + (r.nextDouble() * 2045)) - 1023; // 2045 rather than 2046 as a safety margin
aoqi@0:       double x = Math.abs(Double.longBitsToDouble(r.nextLong()));
aoqi@0:       while (x != x) {
aoqi@0:         x = Math.abs(Double.longBitsToDouble(r.nextLong()));
aoqi@0:       }
aoqi@0:       double logx = Math.log(x) / Math.log(2);
aoqi@0:       double y = ylogx / logx;
aoqi@0: 
aoqi@0:       res[i][0] = x;
aoqi@0:       res[i][1] = y;
aoqi@0:     }
aoqi@0:     return res;
aoqi@0:   }
aoqi@0: 
aoqi@0:   static double[] exp_values(int nb) {
aoqi@0:     double[] res = new double[nb];
aoqi@0:     for (int i = 0; i < nb; i++) {
aoqi@0:       double ylogx = (1 + (r.nextDouble() * 2045)) - 1023; // 2045 rather than 2046 as a safety margin
aoqi@0:       double x = Math.E;
aoqi@0:       double logx = Math.log(x) / Math.log(2);
aoqi@0:       double y = ylogx / logx;
aoqi@0:       res[i] = y;
aoqi@0:     }
aoqi@0:     return res;
aoqi@0:   }
aoqi@0: 
aoqi@0:   static public void main(String[] args) {
aoqi@0:     {
aoqi@0:       // warmup
aoqi@0:       double[][] warmup_values = pow_values(10);
aoqi@0:       m_pow(warmup_values);
aoqi@0: 
aoqi@0:       for (int i = 0; i < 20000; i++) {
aoqi@0:         m_pow(warmup_values);
aoqi@0:       }
aoqi@0:       // test pow perf
aoqi@0:       double[][] values = pow_values(1000000);
aoqi@0:       System.out.println("==> POW " + m_pow(values));
aoqi@0: 
aoqi@0:       // force uncommon trap
aoqi@0:       double[][] nan_values = new double[1][2];
aoqi@0:       nan_values[0][0] = Double.NaN;
aoqi@0:       nan_values[0][1] = Double.NaN;
aoqi@0:       m_pow(nan_values);
aoqi@0: 
aoqi@0:       // force recompilation
aoqi@0:       for (int i = 0; i < 20000; i++) {
aoqi@0:         m_pow(warmup_values);
aoqi@0:       }
aoqi@0: 
aoqi@0:       // test pow perf again
aoqi@0:       System.out.println("==> POW " + m_pow(values));
aoqi@0:     }
aoqi@0:     {
aoqi@0:       // warmup
aoqi@0:       double[] warmup_values = exp_values(10);
aoqi@0:       m_exp(warmup_values);
aoqi@0: 
aoqi@0:       for (int i = 0; i < 20000; i++) {
aoqi@0:         m_exp(warmup_values);
aoqi@0:       }
aoqi@0: 
aoqi@0:       // test pow perf
aoqi@0:       double[] values = exp_values(1000000);
aoqi@0:       System.out.println("==> EXP " + m_exp(values));
aoqi@0: 
aoqi@0:       // force uncommon trap
aoqi@0:       double[] nan_values = new double[1];
aoqi@0:       nan_values[0] = Double.NaN;
aoqi@0:       m_exp(nan_values);
aoqi@0: 
aoqi@0:       // force recompilation
aoqi@0:       for (int i = 0; i < 20000; i++) {
aoqi@0:         m_exp(warmup_values);
aoqi@0:       }
aoqi@0: 
aoqi@0:       // test pow perf again
aoqi@0:       System.out.println("==> EXP " + m_exp(values));
aoqi@0:     }
aoqi@0:   }
aoqi@0: }