mirror of
https://github.com/pineappleEA/pineapple-src.git
synced 2024-12-04 22:58:24 -05:00
68 lines
2.0 KiB
C
Executable File
68 lines
2.0 KiB
C
Executable File
/*
|
|
* copyright (c) 2016 Ganesh Ajjanagadde <gajjanag@gmail.com>
|
|
*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* FFmpeg is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* FFmpeg is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with FFmpeg; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
/**
|
|
* @file
|
|
* internal math functions header
|
|
*/
|
|
|
|
#ifndef AVUTIL_FFMATH_H
|
|
#define AVUTIL_FFMATH_H
|
|
|
|
#include "attributes.h"
|
|
#include "libm.h"
|
|
|
|
/**
|
|
* Compute 10^x for floating point values. Note: this function is by no means
|
|
* "correctly rounded", and is meant as a fast, reasonably accurate approximation.
|
|
* For instance, maximum relative error for the double precision variant is
|
|
* ~ 1e-13 for very small and very large values.
|
|
* This is ~2x faster than GNU libm's approach, which is still off by 2ulp on
|
|
* some inputs.
|
|
* @param x exponent
|
|
* @return 10^x
|
|
*/
|
|
static av_always_inline double ff_exp10(double x)
|
|
{
|
|
return exp2(M_LOG2_10 * x);
|
|
}
|
|
|
|
static av_always_inline float ff_exp10f(float x)
|
|
{
|
|
return exp2f(M_LOG2_10 * x);
|
|
}
|
|
|
|
/**
|
|
* Compute x^y for floating point x, y. Note: this function is faster than the
|
|
* libm variant due to mainly 2 reasons:
|
|
* 1. It does not handle any edge cases. In particular, this is only guaranteed
|
|
* to work correctly for x > 0.
|
|
* 2. It is not as accurate as a standard nearly "correctly rounded" libm variant.
|
|
* @param x base
|
|
* @param y exponent
|
|
* @return x^y
|
|
*/
|
|
static av_always_inline float ff_fast_powf(float x, float y)
|
|
{
|
|
return expf(logf(x) * y);
|
|
}
|
|
|
|
#endif /* AVUTIL_FFMATH_H */
|