x - \frac{\log \left(\left(1 - y\right) + y \cdot e^{z}\right)}{t}\begin{array}{l}
\mathbf{if}\;z \le -5.2073484199518872 \cdot 10^{-38} \lor \neg \left(z \le 1.8330086343134758 \cdot 10^{-124} \lor \neg \left(z \le 3.2223812747103702 \cdot 10^{-17}\right)\right):\\
\;\;\;\;x - \log \left(\mathsf{fma}\left(\mathsf{expm1}\left(z\right), y, 1\right)\right) \cdot \frac{1}{t}\\
\mathbf{else}:\\
\;\;\;\;x - \mathsf{fma}\left(0.5, {z}^{2} \cdot y, \mathsf{fma}\left(1, z \cdot y, \log 1\right)\right) \cdot \frac{1}{t}\\
\end{array}double f(double x, double y, double z, double t) {
double r352294 = x;
double r352295 = 1.0;
double r352296 = y;
double r352297 = r352295 - r352296;
double r352298 = z;
double r352299 = exp(r352298);
double r352300 = r352296 * r352299;
double r352301 = r352297 + r352300;
double r352302 = log(r352301);
double r352303 = t;
double r352304 = r352302 / r352303;
double r352305 = r352294 - r352304;
return r352305;
}
double f(double x, double y, double z, double t) {
double r352306 = z;
double r352307 = -5.207348419951887e-38;
bool r352308 = r352306 <= r352307;
double r352309 = 1.8330086343134758e-124;
bool r352310 = r352306 <= r352309;
double r352311 = 3.22238127471037e-17;
bool r352312 = r352306 <= r352311;
double r352313 = !r352312;
bool r352314 = r352310 || r352313;
double r352315 = !r352314;
bool r352316 = r352308 || r352315;
double r352317 = x;
double r352318 = expm1(r352306);
double r352319 = y;
double r352320 = 1.0;
double r352321 = fma(r352318, r352319, r352320);
double r352322 = log(r352321);
double r352323 = 1.0;
double r352324 = t;
double r352325 = r352323 / r352324;
double r352326 = r352322 * r352325;
double r352327 = r352317 - r352326;
double r352328 = 0.5;
double r352329 = 2.0;
double r352330 = pow(r352306, r352329);
double r352331 = r352330 * r352319;
double r352332 = r352306 * r352319;
double r352333 = log(r352320);
double r352334 = fma(r352320, r352332, r352333);
double r352335 = fma(r352328, r352331, r352334);
double r352336 = r352335 * r352325;
double r352337 = r352317 - r352336;
double r352338 = r352316 ? r352327 : r352337;
return r352338;
}




Bits error versus x




Bits error versus y




Bits error versus z




Bits error versus t
| Original | 25.2 |
|---|---|
| Target | 16.2 |
| Herbie | 8.8 |
if z < -5.207348419951887e-38 or 1.8330086343134758e-124 < z < 3.22238127471037e-17Initial program 18.0
Simplified11.8
rmApplied div-inv11.8
if -5.207348419951887e-38 < z < 1.8330086343134758e-124 or 3.22238127471037e-17 < z Initial program 31.1
Simplified11.2
rmApplied div-inv11.2
rmApplied add-cbrt-cube11.3
Simplified11.3
Taylor expanded around 0 6.3
Simplified6.3
Final simplification8.8
herbie shell --seed 2020042 +o rules:numerics
(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)))