/*

 * Copyright (c) Radzivon Bartoshyk, 10/2024. All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without modification,

 * are permitted provided that the following conditions are met:

 *

 * 1.  Redistributions of source code must retain the above copyright notice, this

 * list of conditions and the following disclaimer.

 *

 * 2.  Redistributions in binary form must reproduce the above copyright notice,

 * this list of conditions and the following disclaimer in the documentation

 * and/or other materials provided with the distribution.

 *

 * 3.  Neither the name of the copyright holder nor the names of its

 * contributors may be used to endorse or promote products derived from

 * this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

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 */

use crate::math::consts::ConstPI;

use num_traits::{AsPrimitive, Float, Signed};

#[inline(always)]

pub(crate) fn sphinx<V: Copy + ConstPI + Signed + Float + 'static>(x: V) -> V

where

    f32: AsPrimitive<V>,

{

    if x.abs() < 1e-8.as_() {

        return 1f32.as_();

    }

    let x = x * V::const_pi();

    3.0f32.as_() * (x.sin() - x * x.cos()) / (x * x * x)

}