| // Copyright 2014 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // Flags: --no-fast-math |
| |
| assertTrue(isNaN(Math.expm1(NaN))); |
| assertTrue(isNaN(Math.expm1(function() {}))); |
| assertTrue(isNaN(Math.expm1({ toString: function() { return NaN; } }))); |
| assertTrue(isNaN(Math.expm1({ valueOf: function() { return "abc"; } }))); |
| assertEquals("Infinity", String(1/Math.expm1(0))); |
| assertEquals("-Infinity", String(1/Math.expm1(-0))); |
| assertEquals("Infinity", String(Math.expm1(Infinity))); |
| assertEquals(-1, Math.expm1(-Infinity)); |
| |
| for (var x = 0.1; x < 700; x += 0.1) { |
| var expected = Math.exp(x) - 1; |
| assertEqualsDelta(expected, Math.expm1(x), expected * 1E-14); |
| expected = Math.exp(-x) - 1; |
| assertEqualsDelta(expected, Math.expm1(-x), -expected * 1E-14); |
| } |
| |
| // Values close to 0: |
| // Use six terms of Taylor expansion at 0 for exp(x) as test expectation: |
| // exp(x) - 1 == exp(0) + exp(0) * x + x * x / 2 + ... - 1 |
| // == x + x * x / 2 + x * x * x / 6 + ... |
| function expm1(x) { |
| return x * (1 + x * (1/2 + x * ( |
| 1/6 + x * (1/24 + x * ( |
| 1/120 + x * (1/720 + x * ( |
| 1/5040 + x * (1/40320 + x*( |
| 1/362880 + x * (1/3628800)))))))))); |
| } |
| |
| for (var x = 1E-1; x > 1E-300; x *= 0.8) { |
| var expected = expm1(x); |
| assertEqualsDelta(expected, Math.expm1(x), expected * 1E-14); |
| } |