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 r379627 = x;
double r379628 = 1.0;
double r379629 = y;
double r379630 = r379628 - r379629;
double r379631 = z;
double r379632 = exp(r379631);
double r379633 = r379629 * r379632;
double r379634 = r379630 + r379633;
double r379635 = log(r379634);
double r379636 = t;
double r379637 = r379635 / r379636;
double r379638 = r379627 - r379637;
return r379638;
}
double f(double x, double y, double z, double t) {
double r379639 = z;
double r379640 = -5.207348419951887e-38;
bool r379641 = r379639 <= r379640;
double r379642 = 1.8330086343134758e-124;
bool r379643 = r379639 <= r379642;
double r379644 = 3.22238127471037e-17;
bool r379645 = r379639 <= r379644;
double r379646 = !r379645;
bool r379647 = r379643 || r379646;
double r379648 = !r379647;
bool r379649 = r379641 || r379648;
double r379650 = x;
double r379651 = expm1(r379639);
double r379652 = y;
double r379653 = 1.0;
double r379654 = fma(r379651, r379652, r379653);
double r379655 = log(r379654);
double r379656 = 1.0;
double r379657 = t;
double r379658 = r379656 / r379657;
double r379659 = r379655 * r379658;
double r379660 = r379650 - r379659;
double r379661 = 0.5;
double r379662 = 2.0;
double r379663 = pow(r379639, r379662);
double r379664 = r379663 * r379652;
double r379665 = r379639 * r379652;
double r379666 = log(r379653);
double r379667 = fma(r379653, r379665, r379666);
double r379668 = fma(r379661, r379664, r379667);
double r379669 = r379668 * r379658;
double r379670 = r379650 - r379669;
double r379671 = r379649 ? r379660 : r379670;
return r379671;
}




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)))