1 // Copyright 2014 the V8 project authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 assertTrue(isNaN(Math.log1p(NaN))); 6 assertTrue(isNaN(Math.log1p(function() {}))); 7 assertTrue(isNaN(Math.log1p({ toString: function() { return NaN; } }))); 8 assertTrue(isNaN(Math.log1p({ valueOf: function() { return "abc"; } }))); 9 assertEquals(Infinity, 1/Math.log1p(0)); 10 assertEquals(-Infinity, 1/Math.log1p(-0)); 11 assertEquals(Infinity, Math.log1p(Infinity)); 12 assertEquals(-Infinity, Math.log1p(-1)); 13 assertTrue(isNaN(Math.log1p(-2))); 14 assertTrue(isNaN(Math.log1p(-Infinity))); 15 16 for (var x = 1E300; x > 1E16; x *= 0.8) { 17 var expected = Math.log(x + 1); 18 assertEqualsDelta(expected, Math.log1p(x), expected * 1E-16); 19 } 20 21 // Values close to 0: 22 // Use Taylor expansion at 1 for log(x) as test expectation: 23 // log1p(x) == log(x + 1) == 0 + x / 1 - x^2 / 2 + x^3 / 3 - ... 24 function log1p(x) { 25 var terms = []; 26 var prod = x; 27 for (var i = 1; i <= 20; i++) { 28 terms.push(prod / i); 29 prod *= -x; 30 } 31 var sum = 0; 32 while (terms.length > 0) sum += terms.pop(); 33 return sum; 34 } 35 36 for (var x = 1E-1; x > 1E-300; x *= 0.8) { 37 var expected = log1p(x); 38 assertEqualsDelta(expected, Math.log1p(x), expected * 1E-16); 39 } 40 41 // Issue 3481. 42 assertEquals(6.9756137364252422e-03, 43 Math.log1p(8070450532247929/Math.pow(2,60))); 44 45 // Tests related to the fdlibm implementation. 46 // Test largest double value. 47 assertEquals(709.782712893384, Math.log1p(1.7976931348623157e308)); 48 // Test small values. 49 assertEquals(Math.pow(2, -55), Math.log1p(Math.pow(2, -55))); 50 assertEquals(9.313225741817976e-10, Math.log1p(Math.pow(2, -30))); 51 // Cover various code paths. 52 // -.2929 < x < .41422, k = 0 53 assertEquals(-0.2876820724517809, Math.log1p(-0.25)); 54 assertEquals(0.22314355131420976, Math.log1p(0.25)); 55 // 0.41422 < x < 9.007e15 56 assertEquals(2.3978952727983707, Math.log1p(10)); 57 // x > 9.007e15 58 assertEquals(36.841361487904734, Math.log1p(10e15)); 59 // Normalize u. 60 assertEquals(37.08337388996168, Math.log1p(12738099905822720)); 61 // Normalize u/2. 62 assertEquals(37.08336444902049, Math.log1p(12737979646738432)); 63 // |f| = 0, k != 0 64 assertEquals(1.3862943611198906, Math.log1p(3)); 65 // |f| != 0, k != 0 66 assertEquals(1.3862945995384413, Math.log1p(3 + Math.pow(2,-20))); 67 // final if-clause: k = 0 68 assertEquals(0.5596157879354227, Math.log1p(0.75)); 69 // final if-clause: k != 0 70 assertEquals(0.8109302162163288, Math.log1p(1.25)); 71
