39 lines
1.4 KiB
JavaScript
39 lines
1.4 KiB
JavaScript
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// 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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// Flags: --harmony-maths --no-fast-math
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assertTrue(isNaN(Math.expm1(NaN)));
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assertTrue(isNaN(Math.expm1(function() {})));
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assertTrue(isNaN(Math.expm1({ toString: function() { return NaN; } })));
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assertTrue(isNaN(Math.expm1({ valueOf: function() { return "abc"; } })));
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assertEquals("Infinity", String(1/Math.expm1(0)));
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assertEquals("-Infinity", String(1/Math.expm1(-0)));
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assertEquals("Infinity", String(Math.expm1(Infinity)));
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assertEquals(-1, Math.expm1(-Infinity));
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for (var x = 0.1; x < 700; x += 0.1) {
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var expected = Math.exp(x) - 1;
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assertEqualsDelta(expected, Math.expm1(x), expected * 1E-14);
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expected = Math.exp(-x) - 1;
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assertEqualsDelta(expected, Math.expm1(-x), -expected * 1E-14);
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}
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// Values close to 0:
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// Use six terms of Taylor expansion at 0 for exp(x) as test expectation:
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// exp(x) - 1 == exp(0) + exp(0) * x + x * x / 2 + ... - 1
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// == x + x * x / 2 + x * x * x / 6 + ...
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function expm1(x) {
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return x * (1 + x * (1/2 + x * (
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1/6 + x * (1/24 + x * (
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1/120 + x * (1/720 + x * (
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1/5040 + x * (1/40320 + x*(
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1/362880 + x * (1/3628800))))))))));
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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 = expm1(x);
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assertEqualsDelta(expected, Math.expm1(x), expected * 1E-14);
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}
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