Function approx_parabola_integral_simd 

fn approx_parabola_integral_simd<S: Simd, F: SimdFloat<S, Element = f32>>(
    x: F,
) -> F

An approximation to $\int (1 + 4x^2) ^ -0.25 dx$

This is used for flattening curves.

SIMD version of approx_parabola_integral.