double f(double x, double y) {
double r6787207 = x;
double r6787208 = y;
double r6787209 = r6787207 - r6787208;
double r6787210 = r6787207 + r6787208;
double r6787211 = r6787209 * r6787210;
double r6787212 = r6787207 * r6787207;
double r6787213 = r6787208 * r6787208;
double r6787214 = r6787212 + r6787213;
double r6787215 = r6787211 / r6787214;
return r6787215;
}
double f(double x, double y) {
double r6787216 = y;
double r6787217 = -1.366618915167733e+154;
bool r6787218 = r6787216 <= r6787217;
double r6787219 = -1.0;
double r6787220 = -2.70713010924186e-162;
bool r6787221 = r6787216 <= r6787220;
double r6787222 = x;
double r6787223 = r6787222 - r6787216;
double r6787224 = r6787216 + r6787222;
double r6787225 = r6787223 * r6787224;
double r6787226 = r6787216 * r6787216;
double r6787227 = fma(r6787222, r6787222, r6787226);
double r6787228 = r6787225 / r6787227;
double r6787229 = 3.060862139420529e-162;
bool r6787230 = r6787216 <= r6787229;
double r6787231 = 1.0;
double r6787232 = r6787230 ? r6787231 : r6787228;
double r6787233 = r6787221 ? r6787228 : r6787232;
double r6787234 = r6787218 ? r6787219 : r6787233;
return r6787234;
}
\frac{\left(x - y\right) \cdot \left(x + y\right)}{x \cdot x + y \cdot y}\begin{array}{l}
\mathbf{if}\;y \le -1.366618915167733 \cdot 10^{+154}:\\
\;\;\;\;-1\\
\mathbf{elif}\;y \le -2.70713010924186 \cdot 10^{-162}:\\
\;\;\;\;\frac{\left(x - y\right) \cdot \left(y + x\right)}{(x \cdot x + \left(y \cdot y\right))_*}\\
\mathbf{elif}\;y \le 3.060862139420529 \cdot 10^{-162}:\\
\;\;\;\;1\\
\mathbf{else}:\\
\;\;\;\;\frac{\left(x - y\right) \cdot \left(y + x\right)}{(x \cdot x + \left(y \cdot y\right))_*}\\
\end{array}



Bits error versus x




Bits error versus y
| Original | 19.4 |
|---|---|
| Target | 0.1 |
| Herbie | 4.9 |
if y < -1.366618915167733e+154Initial program 63.6
Simplified63.6
Taylor expanded around 0 0
if -1.366618915167733e+154 < y < -2.70713010924186e-162 or 3.060862139420529e-162 < y Initial program 0.1
Simplified0.1
if -2.70713010924186e-162 < y < 3.060862139420529e-162Initial program 29.0
Simplified29.0
Taylor expanded around inf 15.2
Final simplification4.9
herbie shell --seed 2019102 +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))))