double f(double x, double y) {
double r6591337 = x;
double r6591338 = y;
double r6591339 = r6591337 - r6591338;
double r6591340 = r6591337 + r6591338;
double r6591341 = r6591339 * r6591340;
double r6591342 = r6591337 * r6591337;
double r6591343 = r6591338 * r6591338;
double r6591344 = r6591342 + r6591343;
double r6591345 = r6591341 / r6591344;
return r6591345;
}
double f(double x, double y) {
double r6591346 = y;
double r6591347 = -1.3261488941008737e+154;
bool r6591348 = r6591346 <= r6591347;
double r6591349 = -1.0;
double r6591350 = -6.401413403488955e-157;
bool r6591351 = r6591346 <= r6591350;
double r6591352 = 1.0;
double r6591353 = x;
double r6591354 = r6591346 * r6591346;
double r6591355 = fma(r6591353, r6591353, r6591354);
double r6591356 = r6591353 - r6591346;
double r6591357 = r6591346 + r6591353;
double r6591358 = r6591356 * r6591357;
double r6591359 = r6591355 / r6591358;
double r6591360 = r6591352 / r6591359;
double r6591361 = 1.5746421432035006e-162;
bool r6591362 = r6591346 <= r6591361;
double r6591363 = r6591362 ? r6591352 : r6591360;
double r6591364 = r6591351 ? r6591360 : r6591363;
double r6591365 = r6591348 ? r6591349 : r6591364;
return r6591365;
}
\frac{\left(x - y\right) \cdot \left(x + y\right)}{x \cdot x + y \cdot y}\begin{array}{l}
\mathbf{if}\;y \le -1.3261488941008737 \cdot 10^{+154}:\\
\;\;\;\;-1\\
\mathbf{elif}\;y \le -6.401413403488955 \cdot 10^{-157}:\\
\;\;\;\;\frac{1}{\frac{(x \cdot x + \left(y \cdot y\right))_*}{\left(x - y\right) \cdot \left(y + x\right)}}\\
\mathbf{elif}\;y \le 1.5746421432035006 \cdot 10^{-162}:\\
\;\;\;\;1\\
\mathbf{else}:\\
\;\;\;\;\frac{1}{\frac{(x \cdot x + \left(y \cdot y\right))_*}{\left(x - y\right) \cdot \left(y + x\right)}}\\
\end{array}



Bits error versus x




Bits error versus y
| Original | 19.5 |
|---|---|
| Target | 0.1 |
| Herbie | 4.9 |
if y < -1.3261488941008737e+154Initial program 63.6
Simplified63.6
Taylor expanded around 0 0
if -1.3261488941008737e+154 < y < -6.401413403488955e-157 or 1.5746421432035006e-162 < y Initial program 0.1
Simplified0.0
rmApplied clear-num0.1
if -6.401413403488955e-157 < y < 1.5746421432035006e-162Initial program 28.8
Simplified28.8
Taylor expanded around inf 15.4
Final simplification4.9
herbie shell --seed 2019101 +o rules:numerics
(FPCore (x y)
:name "Kahan p9 Example"
:pre (and (< 0 x 1) (< y 1))
:herbie-target
(if (< 0.5 (fabs (/ x y)) 2) (/ (* (- x y) (+ x y)) (+ (* x x) (* y y))) (- 1 (/ 2 (+ 1 (* (/ x y) (/ x y))))))
(/ (* (- x y) (+ x y)) (+ (* x x) (* y y))))