numaxiom 0.0.2

Lightweight numeric marker traits for ranges/signs plus constants and ops; std by default, no_std optional.
Documentation
/// Arctangent helper.
///
/// Contract (minimum): return the principal value of arctangent. Implementers
/// must document behavior for NaN/∞ inputs and accuracy guarantees.
pub trait Atan: Sized {
    fn atan(self) -> Self;
}

#[cfg(any(feature = "std", feature = "libm"))]
mod float_impls {
    use super::Atan;

    #[inline]
    fn atan_f32(x: f32) -> f32 {
        #[cfg(feature = "libm")]
        {
            libm::atanf(x)
        }
        #[cfg(not(feature = "libm"))]
        {
            f32::atan(x)
        }
    }

    #[inline]
    fn atan_f64(x: f64) -> f64 {
        #[cfg(feature = "libm")]
        {
            libm::atan(x)
        }
        #[cfg(not(feature = "libm"))]
        {
            f64::atan(x)
        }
    }

    macro_rules! impl_atan_for_float {
        ($ty:ty, $fn:ident) => {
            impl Atan for $ty {
                fn atan(self) -> Self {
                    $fn(self)
                }
            }
        };
    }

    impl_atan_for_float!(f32, atan_f32);
    impl_atan_for_float!(f64, atan_f64);
}