\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 r62092 = 1.0;
double r62093 = k;
double r62094 = sqrt(r62093);
double r62095 = r62092 / r62094;
double r62096 = 2.0;
double r62097 = atan2(1.0, 0.0);
double r62098 = r62096 * r62097;
double r62099 = n;
double r62100 = r62098 * r62099;
double r62101 = r62092 - r62093;
double r62102 = r62101 / r62096;
double r62103 = pow(r62100, r62102);
double r62104 = r62095 * r62103;
return r62104;
}
double f(double k, double n) {
double r62105 = 1.0;
double r62106 = k;
double r62107 = sqrt(r62106);
double r62108 = r62105 / r62107;
double r62109 = 2.0;
double r62110 = atan2(1.0, 0.0);
double r62111 = r62109 * r62110;
double r62112 = n;
double r62113 = r62111 * r62112;
double r62114 = r62105 - r62106;
double r62115 = r62114 / r62109;
double r62116 = 2.0;
double r62117 = r62115 / r62116;
double r62118 = pow(r62113, r62117);
double r62119 = r62108 * r62118;
double r62120 = pow(r62109, r62115);
double r62121 = r62110 * r62112;
double r62122 = pow(r62121, r62115);
double r62123 = r62120 * r62122;
double r62124 = 0.5;
double r62125 = pow(r62123, r62124);
double r62126 = r62119 * r62125;
return r62126;
}



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))))