0f81d7698a
Port contributed by Raymond Toy <rtoy@google.com>. R=rtoy@chromium.org LOG=N BUG=v8:3481 Review URL: https://codereview.chromium.org/457643002 git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23082 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
71 lines
2.4 KiB
JavaScript
71 lines
2.4 KiB
JavaScript
// Copyright 2014 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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assertTrue(isNaN(Math.log1p(NaN)));
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assertTrue(isNaN(Math.log1p(function() {})));
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assertTrue(isNaN(Math.log1p({ toString: function() { return NaN; } })));
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assertTrue(isNaN(Math.log1p({ valueOf: function() { return "abc"; } })));
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assertEquals(Infinity, 1/Math.log1p(0));
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assertEquals(-Infinity, 1/Math.log1p(-0));
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assertEquals(Infinity, Math.log1p(Infinity));
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assertEquals(-Infinity, Math.log1p(-1));
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assertTrue(isNaN(Math.log1p(-2)));
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assertTrue(isNaN(Math.log1p(-Infinity)));
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for (var x = 1E300; x > 1E16; x *= 0.8) {
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var expected = Math.log(x + 1);
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assertEqualsDelta(expected, Math.log1p(x), expected * 1E-16);
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}
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// Values close to 0:
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// Use Taylor expansion at 1 for log(x) as test expectation:
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// log1p(x) == log(x + 1) == 0 + x / 1 - x^2 / 2 + x^3 / 3 - ...
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function log1p(x) {
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var terms = [];
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var prod = x;
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for (var i = 1; i <= 20; i++) {
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terms.push(prod / i);
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prod *= -x;
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}
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var sum = 0;
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while (terms.length > 0) sum += terms.pop();
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return sum;
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}
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for (var x = 1E-1; x > 1E-300; x *= 0.8) {
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var expected = log1p(x);
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assertEqualsDelta(expected, Math.log1p(x), expected * 1E-16);
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}
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// Issue 3481.
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assertEquals(6.9756137364252422e-03,
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Math.log1p(8070450532247929/Math.pow(2,60)));
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// Tests related to the fdlibm implementation.
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// Test largest double value.
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assertEquals(709.782712893384, Math.log1p(1.7976931348623157e308));
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// Test small values.
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assertEquals(Math.pow(2, -55), Math.log1p(Math.pow(2, -55)));
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assertEquals(9.313225741817976e-10, Math.log1p(Math.pow(2, -30)));
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// Cover various code paths.
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// -.2929 < x < .41422, k = 0
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assertEquals(-0.2876820724517809, Math.log1p(-0.25));
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assertEquals(0.22314355131420976, Math.log1p(0.25));
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// 0.41422 < x < 9.007e15
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assertEquals(2.3978952727983707, Math.log1p(10));
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// x > 9.007e15
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assertEquals(36.841361487904734, Math.log1p(10e15));
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// Normalize u.
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assertEquals(37.08337388996168, Math.log1p(12738099905822720));
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// Normalize u/2.
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assertEquals(37.08336444902049, Math.log1p(12737979646738432));
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// |f| = 0, k != 0
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assertEquals(1.3862943611198906, Math.log1p(3));
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// |f| != 0, k != 0
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assertEquals(1.3862945995384413, Math.log1p(3 + Math.pow(2,-20)));
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// final if-clause: k = 0
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assertEquals(0.5596157879354227, Math.log1p(0.75));
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// final if-clause: k != 0
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assertEquals(0.8109302162163288, Math.log1p(1.25));
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