\tan \left(x + \varepsilon\right) - \tan x
\begin{array}{l}
\mathbf{if}\;\varepsilon \le -6.844251912285020723082132168526967873585 \cdot 10^{-54}:\\
\;\;\;\;\frac{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon} \cdot \frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon} - \tan x \cdot \tan x}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon} + \tan x}\\
\mathbf{elif}\;\varepsilon \le 7.898055614722724574412272427378393232998 \cdot 10^{-140}:\\
\;\;\;\;\left(\varepsilon \cdot x\right) \cdot \left(x + \varepsilon\right) + \varepsilon\\
\mathbf{else}:\\
\;\;\;\;\frac{\left(\tan x + \tan \varepsilon\right) \cdot \cos x - \left(1 - \tan x \cdot \tan \varepsilon\right) \cdot \sin x}{\left(1 - \tan x \cdot \tan \varepsilon\right) \cdot \cos x}\\
\end{array}double f(double x, double eps) {
double r159689 = x;
double r159690 = eps;
double r159691 = r159689 + r159690;
double r159692 = tan(r159691);
double r159693 = tan(r159689);
double r159694 = r159692 - r159693;
return r159694;
}
double f(double x, double eps) {
double r159695 = eps;
double r159696 = -6.844251912285021e-54;
bool r159697 = r159695 <= r159696;
double r159698 = x;
double r159699 = tan(r159698);
double r159700 = tan(r159695);
double r159701 = r159699 + r159700;
double r159702 = 1.0;
double r159703 = r159699 * r159700;
double r159704 = r159702 - r159703;
double r159705 = r159701 / r159704;
double r159706 = r159705 * r159705;
double r159707 = r159699 * r159699;
double r159708 = r159706 - r159707;
double r159709 = r159705 + r159699;
double r159710 = r159708 / r159709;
double r159711 = 7.898055614722725e-140;
bool r159712 = r159695 <= r159711;
double r159713 = r159695 * r159698;
double r159714 = r159698 + r159695;
double r159715 = r159713 * r159714;
double r159716 = r159715 + r159695;
double r159717 = cos(r159698);
double r159718 = r159701 * r159717;
double r159719 = sin(r159698);
double r159720 = r159704 * r159719;
double r159721 = r159718 - r159720;
double r159722 = r159704 * r159717;
double r159723 = r159721 / r159722;
double r159724 = r159712 ? r159716 : r159723;
double r159725 = r159697 ? r159710 : r159724;
return r159725;
}




Bits error versus x




Bits error versus eps
Results
| Original | 37.5 |
|---|---|
| Target | 15.0 |
| Herbie | 16.6 |
if eps < -6.844251912285021e-54Initial program 30.1
rmApplied tan-sum4.3
rmApplied flip--4.4
if -6.844251912285021e-54 < eps < 7.898055614722725e-140Initial program 48.9
Taylor expanded around 0 32.2
Simplified31.9
if 7.898055614722725e-140 < eps Initial program 32.7
rmApplied tan-quot32.5
Applied tan-sum12.0
Applied frac-sub12.0
Final simplification16.6
herbie shell --seed 2019353
(FPCore (x eps)
:name "2tan (problem 3.3.2)"
:precision binary64
:herbie-target
(/ (sin eps) (* (cos x) (cos (+ x eps))))
(- (tan (+ x eps)) (tan x)))