src/core/utils/Math.h

/*
 * Copyright (c) 2023 Arm Limited.
 *
 * SPDX-License-Identifier: MIT
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#ifndef ACL_SRC_CORE_UTILS_MATH_H
#define ACL_SRC_CORE_UTILS_MATH_H

#include <array>

namespace arm_compute
{

/** Lookup table for erf(x) calculation. */
template <typename T>
struct ErfLutEntry
{
    /** erf(x) */
    T value;

    /** 2 / sqrt(pi) * e^(-x^2) */
    T scale;
};

/** The lookup table for FP32 erf(x) calculation. */
extern const std::array<ErfLutEntry<float>, 513> erf_f32_lut;

} // namespace arm_compute

#endif // ACL_SRC_CORE_UTILS_MATH_H