\sqrt{0.5 \cdot \left(1 + \frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}}\right)}\log \left(e^{\frac{\sqrt{\left(\left(\frac{x \cdot x}{\sqrt{\sqrt{p \cdot \left(p \cdot 4\right) + x \cdot x}} \cdot \sqrt{\sqrt{p \cdot \left(p \cdot 4\right) + x \cdot x}}} \cdot \frac{x}{p \cdot \left(p \cdot 4\right) + x \cdot x}\right) \cdot 0.5 + 0.5\right) \cdot \left(0.5 \cdot 0.5\right)}}{\sqrt{\left(\frac{x}{\sqrt{p \cdot \left(p \cdot 4\right) + x \cdot x}} \cdot 0.5\right) \cdot \left(\frac{x}{\sqrt{p \cdot \left(p \cdot 4\right) + x \cdot x}} \cdot 0.5\right) + \left(0.5 \cdot 0.5 - 0.5 \cdot \left(\frac{x}{\sqrt{p \cdot \left(p \cdot 4\right) + x \cdot x}} \cdot 0.5\right)\right)}}}\right)double f(double p, double x) {
double r67967689 = 0.5;
double r67967690 = 1.0;
double r67967691 = x;
double r67967692 = 4.0;
double r67967693 = p;
double r67967694 = r67967692 * r67967693;
double r67967695 = r67967694 * r67967693;
double r67967696 = r67967691 * r67967691;
double r67967697 = r67967695 + r67967696;
double r67967698 = sqrt(r67967697);
double r67967699 = r67967691 / r67967698;
double r67967700 = r67967690 + r67967699;
double r67967701 = r67967689 * r67967700;
double r67967702 = sqrt(r67967701);
return r67967702;
}
double f(double p, double x) {
double r67967703 = x;
double r67967704 = r67967703 * r67967703;
double r67967705 = p;
double r67967706 = 4.0;
double r67967707 = r67967705 * r67967706;
double r67967708 = r67967705 * r67967707;
double r67967709 = r67967708 + r67967704;
double r67967710 = sqrt(r67967709);
double r67967711 = sqrt(r67967710);
double r67967712 = r67967711 * r67967711;
double r67967713 = r67967704 / r67967712;
double r67967714 = r67967703 / r67967709;
double r67967715 = r67967713 * r67967714;
double r67967716 = 0.5;
double r67967717 = r67967715 * r67967716;
double r67967718 = r67967717 + r67967716;
double r67967719 = r67967716 * r67967716;
double r67967720 = r67967718 * r67967719;
double r67967721 = sqrt(r67967720);
double r67967722 = r67967703 / r67967710;
double r67967723 = r67967722 * r67967716;
double r67967724 = r67967723 * r67967723;
double r67967725 = r67967716 * r67967723;
double r67967726 = r67967719 - r67967725;
double r67967727 = r67967724 + r67967726;
double r67967728 = sqrt(r67967727);
double r67967729 = r67967721 / r67967728;
double r67967730 = exp(r67967729);
double r67967731 = log(r67967730);
return r67967731;
}




Bits error versus p




Bits error versus x
Results
| Original | 13.1 |
|---|---|
| Target | 13.2 |
| Herbie | 14.1 |
Initial program 13.1
Simplified13.1
rmApplied add-log-exp13.2
rmApplied flip3-+13.2
Applied sqrt-div13.2
Simplified13.6
rmApplied add-sqr-sqrt13.6
Applied sqrt-prod14.1
Final simplification14.1
herbie shell --seed 2019121
(FPCore (p x)
:name "Given's Rotation SVD example"
:pre (< 1e-150 (fabs x) 1e+150)
:herbie-target
(sqrt (+ 1/2 (/ (copysign 1/2 x) (hypot 1 (/ (* 2 p) x)))))
(sqrt (* 0.5 (+ 1 (/ x (sqrt (+ (* (* 4 p) p) (* x x))))))))