206 lines
6.8 KiB
C++
206 lines
6.8 KiB
C++
/*
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* Copyright (c) 2018-2020 Arm Limited.
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*
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* SPDX-License-Identifier: MIT
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to
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* deal in the Software without restriction, including without limitation the
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* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#ifndef ARM_COMPUTE_UTILS_ROUNDING_H
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#define ARM_COMPUTE_UTILS_ROUNDING_H
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#include "arm_compute/core/Error.h"
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#include "arm_compute/core/utils/misc/Traits.h"
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#include "support/Requires.h"
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#include "support/ToolchainSupport.h"
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#include <cmath>
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namespace arm_compute
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{
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namespace utils
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{
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namespace rounding
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{
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/** Rounding mode */
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enum class RoundingMode
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{
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TO_ZERO, /**< Round towards zero */
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AWAY_FROM_ZERO, /**< Round away from zero */
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HALF_TO_ZERO, /**< Round half towards from zero */
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HALF_AWAY_FROM_ZERO, /**< Round half away from zero */
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HALF_UP, /**< Round half towards positive infinity */
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HALF_DOWN, /**< Round half towards negative infinity */
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HALF_EVEN /**< Round half towards nearest even */
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};
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/** Round floating-point value with round to zero
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*
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* @tparam T Parameter type. Should be of floating point type.
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*
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* @param[in] value floating-point value to be rounded.
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*
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* @return Floating-point value of rounded @p value.
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*/
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template <typename T, REQUIRES_TA(traits::is_floating_point<T>::value)>
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inline T round_to_zero(T value)
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{
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T res = std::floor(std::fabs(value));
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return (value < 0.f) ? -res : res;
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}
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/** Round floating-point value with round away from zero
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*
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* @tparam T Parameter type. Should be of floating point type.
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*
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* @param[in] value floating-point value to be rounded.
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*
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* @return Floating-point value of rounded @p value.
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*/
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template <typename T, REQUIRES_TA(traits::is_floating_point<T>::value)>
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inline T round_away_from_zero(T value)
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{
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T res = std::ceil(std::fabs(value));
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return (value < 0.f) ? -res : res;
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}
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/** Round floating-point value with half value rounding towards zero.
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*
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* @tparam T Parameter type. Should be of floating point type.
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*
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* @param[in] value floating-point value to be rounded.
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*
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* @return Floating-point value of rounded @p value.
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*/
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template <typename T, REQUIRES_TA(traits::is_floating_point<T>::value)>
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inline T round_half_to_zero(T value)
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{
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T res = T(std::ceil(std::fabs(value) - 0.5f));
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return (value < 0.f) ? -res : res;
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}
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/** Round floating-point value with half value rounding away from zero.
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*
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* @tparam T Parameter type. Should be of floating point type.
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*
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* @param[in] value floating-point value to be rounded.
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*
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* @return Floating-point value of rounded @p value.
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*/
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template <typename T, REQUIRES_TA(traits::is_floating_point<T>::value)>
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inline T round_half_away_from_zero(T value)
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{
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T res = T(std::floor(std::fabs(value) + 0.5f));
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return (value < 0.f) ? -res : res;
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}
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/** Round floating-point value with half value rounding to positive infinity.
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*
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* @tparam T Parameter type. Should be of floating point type.
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*
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* @param[in] value floating-point value to be rounded.
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*
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* @return Floating-point value of rounded @p value.
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*/
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template <typename T, REQUIRES_TA(traits::is_floating_point<T>::value)>
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inline T round_half_up(T value)
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{
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return std::floor(value + 0.5f);
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}
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/** Round floating-point value with half value rounding to negative infinity.
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*
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* @tparam T Parameter type. Should be of floating point type.
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*
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* @param[in] value floating-point value to be rounded.
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*
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* @return Floating-point value of rounded @p value.
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*/
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template <typename T, REQUIRES_TA(traits::is_floating_point<T>::value)>
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inline T round_half_down(T value)
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{
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return std::ceil(value - 0.5f);
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}
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/** Round floating-point value with half value rounding to nearest even.
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*
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* @tparam T Parameter type. Should be of floating point type.
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*
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* @param[in] value floating-point value to be rounded.
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* @param[in] epsilon precision.
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*
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* @return Floating-point value of rounded @p value.
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*/
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template <typename T, REQUIRES_TA(traits::is_floating_point<T>::value)>
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inline T round_half_even(T value, T epsilon = std::numeric_limits<T>::epsilon())
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{
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T positive_value = std::abs(value);
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T ipart = 0;
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std::modf(positive_value, &ipart);
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// If 'value' is exactly halfway between two integers
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if(std::abs(positive_value - (ipart + 0.5f)) < epsilon)
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{
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// If 'ipart' is even then return 'ipart'
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if(std::fmod(ipart, 2.f) < epsilon)
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{
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return support::cpp11::copysign(ipart, value);
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}
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// Else return the nearest even integer
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return support::cpp11::copysign(std::ceil(ipart + 0.5f), value);
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}
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// Otherwise use the usual round to closest
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return support::cpp11::copysign(support::cpp11::round(positive_value), value);
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}
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/** Round floating-point value given a rounding mode
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*
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* @tparam T Parameter type. Should be of floating point type.
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*
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* @param[in] value floating-point value to be rounded.
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* @param[in] rounding_mode Rounding mode to use.
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*
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* @return Floating-point value of rounded @p value.
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*/
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template <typename T, REQUIRES_TA(traits::is_floating_point<T>::value)>
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inline T round(T value, RoundingMode rounding_mode)
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{
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switch(rounding_mode)
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{
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case RoundingMode::TO_ZERO:
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return round_to_zero(value);
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case RoundingMode::AWAY_FROM_ZERO:
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return round_away_from_zero(value);
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case RoundingMode::HALF_TO_ZERO:
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return round_half_to_zero(value);
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case RoundingMode::HALF_AWAY_FROM_ZERO:
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return round_half_away_from_zero(value);
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case RoundingMode::HALF_UP:
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return round_half_up(value);
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case RoundingMode::HALF_DOWN:
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return round_half_down(value);
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case RoundingMode::HALF_EVEN:
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return round_half_even(value);
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default:
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ARM_COMPUTE_ERROR("Unsupported rounding mode!");
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}
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}
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} // namespace rounding
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} // namespace utils
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} // namespace arm_compute
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#endif /*ARM_COMPUTE_UTILS_ROUNDING_H */
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