x - \frac{\log \left(\left(1 - y\right) + y \cdot e^{z}\right)}{t}\begin{array}{l}
\mathbf{if}\;z \le -1.788149422936711126217649570543650854038 \cdot 10^{-10}:\\
\;\;\;\;x - \log \left(e^{z} \cdot y + \left(1 - y\right)\right) \cdot \frac{1}{t}\\
\mathbf{elif}\;z \le 1.548199489295338911120653686915655113605 \cdot 10^{-142} \lor \neg \left(z \le 4.70552617509855223204263570258364278042 \cdot 10^{-18}\right):\\
\;\;\;\;x - \frac{\log 1 + \left(1 \cdot z + {z}^{2} \cdot 0.5\right) \cdot y}{t}\\
\mathbf{else}:\\
\;\;\;\;x - \frac{\log \left(\left(\frac{1}{2} \cdot y\right) \cdot {z}^{2} + \left(y \cdot z + 1\right)\right)}{t}\\
\end{array}double f(double x, double y, double z, double t) {
double r233215 = x;
double r233216 = 1.0;
double r233217 = y;
double r233218 = r233216 - r233217;
double r233219 = z;
double r233220 = exp(r233219);
double r233221 = r233217 * r233220;
double r233222 = r233218 + r233221;
double r233223 = log(r233222);
double r233224 = t;
double r233225 = r233223 / r233224;
double r233226 = r233215 - r233225;
return r233226;
}
double f(double x, double y, double z, double t) {
double r233227 = z;
double r233228 = -1.788149422936711e-10;
bool r233229 = r233227 <= r233228;
double r233230 = x;
double r233231 = exp(r233227);
double r233232 = y;
double r233233 = r233231 * r233232;
double r233234 = 1.0;
double r233235 = r233234 - r233232;
double r233236 = r233233 + r233235;
double r233237 = log(r233236);
double r233238 = 1.0;
double r233239 = t;
double r233240 = r233238 / r233239;
double r233241 = r233237 * r233240;
double r233242 = r233230 - r233241;
double r233243 = 1.548199489295339e-142;
bool r233244 = r233227 <= r233243;
double r233245 = 4.705526175098552e-18;
bool r233246 = r233227 <= r233245;
double r233247 = !r233246;
bool r233248 = r233244 || r233247;
double r233249 = log(r233234);
double r233250 = r233234 * r233227;
double r233251 = 2.0;
double r233252 = pow(r233227, r233251);
double r233253 = 0.5;
double r233254 = r233252 * r233253;
double r233255 = r233250 + r233254;
double r233256 = r233255 * r233232;
double r233257 = r233249 + r233256;
double r233258 = r233257 / r233239;
double r233259 = r233230 - r233258;
double r233260 = 0.5;
double r233261 = r233260 * r233232;
double r233262 = r233261 * r233252;
double r233263 = r233232 * r233227;
double r233264 = r233263 + r233234;
double r233265 = r233262 + r233264;
double r233266 = log(r233265);
double r233267 = r233266 / r233239;
double r233268 = r233230 - r233267;
double r233269 = r233248 ? r233259 : r233268;
double r233270 = r233229 ? r233242 : r233269;
return r233270;
}




Bits error versus x




Bits error versus y




Bits error versus z




Bits error versus t
Results
| Original | 25.3 |
|---|---|
| Target | 16.1 |
| Herbie | 8.5 |
if z < -1.788149422936711e-10Initial program 11.1
rmApplied div-inv11.1
if -1.788149422936711e-10 < z < 1.548199489295339e-142 or 4.705526175098552e-18 < z Initial program 31.6
Taylor expanded around 0 6.5
Simplified6.4
if 1.548199489295339e-142 < z < 4.705526175098552e-18Initial program 31.5
Taylor expanded around 0 11.5
Simplified11.5
Final simplification8.5
herbie shell --seed 2019194
(FPCore (x y z t)
:name "System.Random.MWC.Distributions:truncatedExp from mwc-random-0.13.3.2"
:herbie-target
(if (< z -2.8874623088207947e+119) (- (- x (/ (/ (- 0.5) (* y t)) (* z z))) (* (/ (- 0.5) (* y t)) (/ (/ 2.0 z) (* z z)))) (- x (/ (log (+ 1.0 (* z y))) t)))
(- x (/ (log (+ (- 1.0 y) (* y (exp z)))) t)))