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 // Flags: --harmony-maths --no-fast-math 6 7 assertTrue(isNaN(Math.expm1(NaN))); 8 assertTrue(isNaN(Math.expm1(function() {}))); 9 assertTrue(isNaN(Math.expm1({ toString: function() { return NaN; } }))); 10 assertTrue(isNaN(Math.expm1({ valueOf: function() { return "abc"; } }))); 11 assertEquals("Infinity", String(1/Math.expm1(0))); 12 assertEquals("-Infinity", String(1/Math.expm1(-0))); 13 assertEquals("Infinity", String(Math.expm1(Infinity))); 14 assertEquals(-1, Math.expm1(-Infinity)); 15 16 for (var x = 0.1; x < 700; x += 0.1) { 17 var expected = Math.exp(x) - 1; 18 assertEqualsDelta(expected, Math.expm1(x), expected * 1E-14); 19 expected = Math.exp(-x) - 1; 20 assertEqualsDelta(expected, Math.expm1(-x), -expected * 1E-14); 21 } 22 23 // Values close to 0: 24 // Use six terms of Taylor expansion at 0 for exp(x) as test expectation: 25 // exp(x) - 1 == exp(0) + exp(0) * x + x * x / 2 + ... - 1 26 // == x + x * x / 2 + x * x * x / 6 + ... 27 function expm1(x) { 28 return x * (1 + x * (1/2 + x * ( 29 1/6 + x * (1/24 + x * ( 30 1/120 + x * (1/720 + x * ( 31 1/5040 + x * (1/40320 + x*( 32 1/362880 + x * (1/3628800)))))))))); 33 } 34 35 for (var x = 1E-1; x > 1E-300; x *= 0.8) { 36 var expected = expm1(x); 37 assertEqualsDelta(expected, Math.expm1(x), expected * 1E-14); 38 } 39
