x - \frac{\log \left(\left(1 - y\right) + y \cdot e^{z}\right)}{t}\begin{array}{l}
\mathbf{if}\;z \le -0.0155597802650863076:\\
\;\;\;\;x - \frac{\log \left(\sqrt{\left(1 - y\right) + y \cdot e^{z}}\right) + \log \left(\sqrt{\left(1 - y\right) + y \cdot e^{z}}\right)}{t}\\
\mathbf{elif}\;z \le 4.93108439134458235 \cdot 10^{-25}:\\
\;\;\;\;x - \left(1 \cdot \left(\left(z \cdot y\right) \cdot \frac{1}{t}\right) + \frac{\log 1}{t}\right)\\
\mathbf{else}:\\
\;\;\;\;x - \frac{\log \left(1 + y \cdot \left(\frac{1}{2} \cdot {z}^{2} + z\right)\right)}{t}\\
\end{array}double f(double x, double y, double z, double t) {
double r312441 = x;
double r312442 = 1.0;
double r312443 = y;
double r312444 = r312442 - r312443;
double r312445 = z;
double r312446 = exp(r312445);
double r312447 = r312443 * r312446;
double r312448 = r312444 + r312447;
double r312449 = log(r312448);
double r312450 = t;
double r312451 = r312449 / r312450;
double r312452 = r312441 - r312451;
return r312452;
}
double f(double x, double y, double z, double t) {
double r312453 = z;
double r312454 = -0.015559780265086308;
bool r312455 = r312453 <= r312454;
double r312456 = x;
double r312457 = 1.0;
double r312458 = y;
double r312459 = r312457 - r312458;
double r312460 = exp(r312453);
double r312461 = r312458 * r312460;
double r312462 = r312459 + r312461;
double r312463 = sqrt(r312462);
double r312464 = log(r312463);
double r312465 = r312464 + r312464;
double r312466 = t;
double r312467 = r312465 / r312466;
double r312468 = r312456 - r312467;
double r312469 = 4.931084391344582e-25;
bool r312470 = r312453 <= r312469;
double r312471 = r312453 * r312458;
double r312472 = 1.0;
double r312473 = r312472 / r312466;
double r312474 = r312471 * r312473;
double r312475 = r312457 * r312474;
double r312476 = log(r312457);
double r312477 = r312476 / r312466;
double r312478 = r312475 + r312477;
double r312479 = r312456 - r312478;
double r312480 = 0.5;
double r312481 = 2.0;
double r312482 = pow(r312453, r312481);
double r312483 = r312480 * r312482;
double r312484 = r312483 + r312453;
double r312485 = r312458 * r312484;
double r312486 = r312457 + r312485;
double r312487 = log(r312486);
double r312488 = r312487 / r312466;
double r312489 = r312456 - r312488;
double r312490 = r312470 ? r312479 : r312489;
double r312491 = r312455 ? r312468 : r312490;
return r312491;
}




Bits error versus x




Bits error versus y




Bits error versus z




Bits error versus t
Results
| Original | 24.7 |
|---|---|
| Target | 15.9 |
| Herbie | 8.1 |
if z < -0.015559780265086308Initial program 10.8
rmApplied add-sqr-sqrt10.8
Applied log-prod10.8
if -0.015559780265086308 < z < 4.931084391344582e-25Initial program 30.9
Taylor expanded around 0 6.5
Simplified6.5
Taylor expanded around 0 6.6
rmApplied div-inv6.6
if 4.931084391344582e-25 < z Initial program 26.6
Taylor expanded around 0 14.5
Simplified14.5
Final simplification8.1
herbie shell --seed 2020043
(FPCore (x y z t)
:name "System.Random.MWC.Distributions:truncatedExp from mwc-random-0.13.3.2"
:precision binary64
:herbie-target
(if (< z -2.8874623088207947e+119) (- (- x (/ (/ (- 0.5) (* y t)) (* z z))) (* (/ (- 0.5) (* y t)) (/ (/ 2 z) (* z z)))) (- x (/ (log (+ 1 (* z y))) t)))
(- x (/ (log (+ (- 1 y) (* y (exp z)))) t)))