--- /dev/null Mon Jan 26 16:12:29 2009 +++ new/test/java/lang/Math/Log10Tests.java Mon Jan 26 16:12:28 2009 @@ -0,0 +1,223 @@ +/* + * Copyright 2003 Sun Microsystems, Inc. All Rights Reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + */ + +/* + * @test + * @bug 4074599 4939441 + * @summary Tests for {Math, StrictMath}.log10 + * @author Joseph D. Darcy + */ + +import sun.misc.FpUtils; +import sun.misc.DoubleConsts; + +public class Log10Tests { + private Log10Tests(){} + + static final double infinityD = Double.POSITIVE_INFINITY; + static final double NaNd = Double.NaN; + static final double LN_10 = StrictMath.log(10.0); + + // Initialize shared random number generator + static java.util.Random rand = new java.util.Random(0L); + + static int testLog10Case(double input, double expected) { + int failures=0; + + failures+=Tests.test("Math.log10(double)", input, + Math.log10(input), expected); + + failures+=Tests.test("StrictMath.log10(double)", input, + StrictMath.log10(input), expected); + + return failures; + } + + static int testLog10() { + int failures = 0; + + double [][] testCases = { + {Double.NaN, NaNd}, + {Double.longBitsToDouble(0x7FF0000000000001L), NaNd}, + {Double.longBitsToDouble(0xFFF0000000000001L), NaNd}, + {Double.longBitsToDouble(0x7FF8555555555555L), NaNd}, + {Double.longBitsToDouble(0xFFF8555555555555L), NaNd}, + {Double.longBitsToDouble(0x7FFFFFFFFFFFFFFFL), NaNd}, + {Double.longBitsToDouble(0xFFFFFFFFFFFFFFFFL), NaNd}, + {Double.longBitsToDouble(0x7FFDeadBeef00000L), NaNd}, + {Double.longBitsToDouble(0xFFFDeadBeef00000L), NaNd}, + {Double.longBitsToDouble(0x7FFCafeBabe00000L), NaNd}, + {Double.longBitsToDouble(0xFFFCafeBabe00000L), NaNd}, + {Double.NEGATIVE_INFINITY, NaNd}, + {-8.0, NaNd}, + {-1.0, NaNd}, + {-DoubleConsts.MIN_NORMAL, NaNd}, + {-Double.MIN_VALUE, NaNd}, + {-0.0, -infinityD}, + {+0.0, -infinityD}, + {+1.0, 0.0}, + {Double.POSITIVE_INFINITY, infinityD}, + }; + + // Test special cases + for(int i = 0; i < testCases.length; i++) { + failures += testLog10Case(testCases[i][0], + testCases[i][1]); + } + + // Test log10(10^n) == n for integer n; 10^n, n < 0 is not + // exactly representable as a floating-point value -- up to + // 10^22 can be represented exactly + double testCase = 1.0; + for(int i = 0; i < 23; i++) { + failures += testLog10Case(testCase, i); + testCase *= 10.0; + } + + // Test for gross inaccuracy by comparing to log; should be + // within a few ulps of log(x)/log(10) + for(int i = 0; i < 10000; i++) { + double input = Double.longBitsToDouble(rand.nextLong()); + if(! FpUtils.isFinite(input)) + continue; // avoid testing NaN and infinite values + else { + input = Math.abs(input); + + double expected = StrictMath.log(input)/LN_10; + if( ! FpUtils.isFinite(expected)) + continue; // if log(input) overflowed, try again + else { + double result; + + if( Math.abs(((result=Math.log10(input)) - expected)/Math.ulp(expected)) > 3) { + failures++; + System.err.println("For input " + input + + ", Math.log10 was more than 3 ulps different from " + + "log(input)/log(10): log10(input) = " + result + + "\tlog(input)/log(10) = " + expected); + } + + if( Math.abs(((result=StrictMath.log10(input)) - expected)/Math.ulp(expected)) > 3) { + failures++; + System.err.println("For input " + input + + ", StrictMath.log10 was more than 3 ulps different from " + + "log(input)/log(10): log10(input) = " + result + + "\tlog(input)/log(10) = " + expected); + } + + + } + } + } + + // Test for accuracy and monotonicity near log10(1.0). From + // the Taylor expansion of log, + // log10(1+z) ~= (z -(z^2)/2)/LN_10; + { + double neighbors[] = new double[40]; + double neighborsStrict[] = new double[40]; + double z = Double.NaN; + + // Test inputs greater than 1.0. + neighbors[0] = Math.log10(1.0); + neighborsStrict[0] = StrictMath.log10(1.0); + + double input[] = new double[40]; + int half = input.length/2; + + + // Initialize input to the 40 consecutive double values + // "centered" at 1.0. + double up = Double.NaN; + double down = Double.NaN; + for(int i = 0; i < half; i++) { + if (i == 0) { + input[half] = 1.0; + up = FpUtils.nextUp(1.0); + down = FpUtils.nextDown(1.0); + } else { + input[half + i] = up; + input[half - i] = down; + up = FpUtils.nextUp(up); + down = FpUtils.nextDown(down); + } + } + input[0] = FpUtils.nextDown(input[1]); + + for(int i = 0; i < neighbors.length; i++) { + neighbors[i] = Math.log10(input[i]); + neighborsStrict[i] = StrictMath.log10(input[i]); + + // Test accuracy. + z = input[i] - 1.0; + double expected = (z - (z*z)*0.5)/LN_10; + if ( Math.abs(neighbors[i] - expected ) > 3*Math.ulp(expected) ) { + failures++; + System.err.println("For input near 1.0 " + input[i] + + ", Math.log10(1+z) was more than 3 ulps different from " + + "(z-(z^2)/2)/ln(10): log10(input) = " + neighbors[i] + + "\texpected about = " + expected); + } + + if ( Math.abs(neighborsStrict[i] - expected ) > 3*Math.ulp(expected) ) { + failures++; + System.err.println("For input near 1.0 " + input[i] + + ", StrictMath.log10(1+z) was more than 3 ulps different from " + + "(z-(z^2)/2)/ln(10): log10(input) = " + neighborsStrict[i] + + "\texpected about = " + expected); + } + + // Test monotonicity + if( i > 0) { + if( neighbors[i-1] > neighbors[i] ) { + failures++; + System.err.println("Monotonicity failure for Math.log10 at " + input[i] + + " and prior value."); + } + + if( neighborsStrict[i-1] > neighborsStrict[i] ) { + failures++; + System.err.println("Monotonicity failure for StrictMath.log10 at " + input[i] + + " and prior value."); + } + } + } + + } + + return failures; + } + + public static void main(String argv[]) { + int failures = 0; + + failures += testLog10(); + + if (failures > 0) { + System.err.println("Testing log10 incurred " + + failures + " failures."); + throw new RuntimeException(); + } + } + +}