/*

 * 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

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 */

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

use num_traits::{AsPrimitive, Float};

use std::ops::{Mul, MulAssign, Neg};

#[inline(always)]

pub(crate) fn gaussian<

    V: ConstPI + Copy + Neg<Output = V> + Mul<Output = V> + MulAssign + 'static + Float,

>(

    x: V,

) -> V

where

    f32: AsPrimitive<V>,

{

    let sigma: V = 0.35f32.as_();

    let pi = V::const_pi();

    let mut den = 2f32.as_() * sigma * sigma;

    den *= den;

    (1f32.as_() / ((2f32.as_() * pi).sqrt() * sigma)) * (-x / den).exp()

}