\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)}\left(\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\left(\frac{\frac{1 - k}{2}}{2}\right)}\right) \cdot {\left({2}^{\left(\frac{1 - k}{2}\right)} \cdot {\left(\pi \cdot n\right)}^{\left(\frac{1 - k}{2}\right)}\right)}^{\frac{1}{2}}double f(double k, double n) {
double r86862 = 1.0;
double r86863 = k;
double r86864 = sqrt(r86863);
double r86865 = r86862 / r86864;
double r86866 = 2.0;
double r86867 = atan2(1.0, 0.0);
double r86868 = r86866 * r86867;
double r86869 = n;
double r86870 = r86868 * r86869;
double r86871 = r86862 - r86863;
double r86872 = r86871 / r86866;
double r86873 = pow(r86870, r86872);
double r86874 = r86865 * r86873;
return r86874;
}
double f(double k, double n) {
double r86875 = 1.0;
double r86876 = k;
double r86877 = sqrt(r86876);
double r86878 = r86875 / r86877;
double r86879 = 2.0;
double r86880 = atan2(1.0, 0.0);
double r86881 = r86879 * r86880;
double r86882 = n;
double r86883 = r86881 * r86882;
double r86884 = r86875 - r86876;
double r86885 = r86884 / r86879;
double r86886 = 2.0;
double r86887 = r86885 / r86886;
double r86888 = pow(r86883, r86887);
double r86889 = r86878 * r86888;
double r86890 = pow(r86879, r86885);
double r86891 = r86880 * r86882;
double r86892 = pow(r86891, r86885);
double r86893 = r86890 * r86892;
double r86894 = 0.5;
double r86895 = pow(r86893, r86894);
double r86896 = r86889 * r86895;
return r86896;
}



Bits error versus k



Bits error versus n
Results
Initial program 0.4
rmApplied sqr-pow0.5
Applied associate-*r*0.5
rmApplied div-inv0.5
Applied pow-unpow0.5
Simplified0.5
rmApplied add-cube-cbrt0.5
Applied associate-*l*0.5
rmApplied unpow-prod-down0.5
Simplified0.4
Final simplification0.4
herbie shell --seed 2019323 +o rules:numerics
(FPCore (k n)
:name "Migdal et al, Equation (51)"
:precision binary64
(* (/ 1 (sqrt k)) (pow (* (* 2 PI) n) (/ (- 1 k) 2))))