| Line | Branch | Exec | Source |
|---|---|---|---|
| 1 | /* | ||
| 2 | * copyright (c) 2016 Ganesh Ajjanagadde <gajjanag@gmail.com> | ||
| 3 | * | ||
| 4 | * This file is part of FFmpeg. | ||
| 5 | * | ||
| 6 | * FFmpeg is free software; you can redistribute it and/or | ||
| 7 | * modify it under the terms of the GNU Lesser General Public | ||
| 8 | * License as published by the Free Software Foundation; either | ||
| 9 | * version 2.1 of the License, or (at your option) any later version. | ||
| 10 | * | ||
| 11 | * FFmpeg is distributed in the hope that it will be useful, | ||
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | ||
| 14 | * Lesser General Public License for more details. | ||
| 15 | * | ||
| 16 | * You should have received a copy of the GNU Lesser General Public | ||
| 17 | * License along with FFmpeg; if not, write to the Free Software | ||
| 18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | ||
| 19 | */ | ||
| 20 | |||
| 21 | /** | ||
| 22 | * @file | ||
| 23 | * internal math functions header | ||
| 24 | */ | ||
| 25 | |||
| 26 | #ifndef AVUTIL_FFMATH_H | ||
| 27 | #define AVUTIL_FFMATH_H | ||
| 28 | |||
| 29 | #include "attributes.h" | ||
| 30 | #include "libm.h" | ||
| 31 | |||
| 32 | /** | ||
| 33 | * Compute 10^x for floating point values. Note: this function is by no means | ||
| 34 | * "correctly rounded", and is meant as a fast, reasonably accurate approximation. | ||
| 35 | * For instance, maximum relative error for the double precision variant is | ||
| 36 | * ~ 1e-13 for very small and very large values. | ||
| 37 | * This is ~2x faster than GNU libm's approach, which is still off by 2ulp on | ||
| 38 | * some inputs. | ||
| 39 | * @param x exponent | ||
| 40 | * @return 10^x | ||
| 41 | */ | ||
| 42 | 264574 | static av_always_inline double ff_exp10(double x) | |
| 43 | { | ||
| 44 | 264574 | return exp2(M_LOG2_10 * x); | |
| 45 | } | ||
| 46 | |||
| 47 | ✗ | static av_always_inline float ff_exp10f(float x) | |
| 48 | { | ||
| 49 | ✗ | return exp2f(M_LOG2_10 * x); | |
| 50 | } | ||
| 51 | |||
| 52 | /** | ||
| 53 | * Compute x^y for floating point x, y. Note: this function is faster than the | ||
| 54 | * libm variant due to mainly 2 reasons: | ||
| 55 | * 1. It does not handle any edge cases. In particular, this is only guaranteed | ||
| 56 | * to work correctly for x > 0. | ||
| 57 | * 2. It is not as accurate as a standard nearly "correctly rounded" libm variant. | ||
| 58 | * @param x base | ||
| 59 | * @param y exponent | ||
| 60 | * @return x^y | ||
| 61 | */ | ||
| 62 | 450145 | static av_always_inline float ff_fast_powf(float x, float y) | |
| 63 | { | ||
| 64 | 450145 | return expf(logf(x) * y); | |
| 65 | } | ||
| 66 | |||
| 67 | #endif /* AVUTIL_FFMATH_H */ | ||
| 68 |