\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)}\frac{{\left(\sqrt{\pi} \cdot \left(n \cdot 2\right)\right)}^{\left(\frac{1}{2} - \frac{k}{2}\right)} \cdot {\left(\sqrt{\pi}\right)}^{\left(\frac{1}{2} - \frac{k}{2}\right)}}{\sqrt{k}}double f(double k, double n) {
double r1642622 = 1.0;
double r1642623 = k;
double r1642624 = sqrt(r1642623);
double r1642625 = r1642622 / r1642624;
double r1642626 = 2.0;
double r1642627 = atan2(1.0, 0.0);
double r1642628 = r1642626 * r1642627;
double r1642629 = n;
double r1642630 = r1642628 * r1642629;
double r1642631 = r1642622 - r1642623;
double r1642632 = r1642631 / r1642626;
double r1642633 = pow(r1642630, r1642632);
double r1642634 = r1642625 * r1642633;
return r1642634;
}
double f(double k, double n) {
double r1642635 = atan2(1.0, 0.0);
double r1642636 = sqrt(r1642635);
double r1642637 = n;
double r1642638 = 2.0;
double r1642639 = r1642637 * r1642638;
double r1642640 = r1642636 * r1642639;
double r1642641 = 0.5;
double r1642642 = k;
double r1642643 = r1642642 / r1642638;
double r1642644 = r1642641 - r1642643;
double r1642645 = pow(r1642640, r1642644);
double r1642646 = pow(r1642636, r1642644);
double r1642647 = r1642645 * r1642646;
double r1642648 = sqrt(r1642642);
double r1642649 = r1642647 / r1642648;
return r1642649;
}



Bits error versus k



Bits error versus n
Results
Initial program 0.4
Simplified0.3
rmApplied add-sqr-sqrt0.4
Applied associate-*r*0.4
rmApplied unpow-prod-down0.4
Final simplification0.4
herbie shell --seed 2019156
(FPCore (k n)
:name "Migdal et al, Equation (51)"
(* (/ 1 (sqrt k)) (pow (* (* 2 PI) n) (/ (- 1 k) 2))))