/*
  * 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 */