\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 r187727 = x;
double r187728 = eps;
double r187729 = r187727 + r187728;
double r187730 = tan(r187729);
double r187731 = tan(r187727);
double r187732 = r187730 - r187731;
return r187732;
}
double f(double x, double eps) {
double r187733 = eps;
double r187734 = -6.844251912285021e-54;
bool r187735 = r187733 <= r187734;
double r187736 = x;
double r187737 = tan(r187736);
double r187738 = tan(r187733);
double r187739 = r187737 + r187738;
double r187740 = 1.0;
double r187741 = r187737 * r187738;
double r187742 = r187740 - r187741;
double r187743 = r187739 / r187742;
double r187744 = r187743 * r187743;
double r187745 = r187737 * r187737;
double r187746 = r187744 - r187745;
double r187747 = r187743 + r187737;
double r187748 = r187746 / r187747;
double r187749 = 7.898055614722725e-140;
bool r187750 = r187733 <= r187749;
double r187751 = r187733 * r187736;
double r187752 = r187736 + r187733;
double r187753 = r187751 * r187752;
double r187754 = r187753 + r187733;
double r187755 = cos(r187736);
double r187756 = r187739 * r187755;
double r187757 = sin(r187736);
double r187758 = r187742 * r187757;
double r187759 = r187756 - r187758;
double r187760 = r187742 * r187755;
double r187761 = r187759 / r187760;
double r187762 = r187750 ? r187754 : r187761;
double r187763 = r187735 ? r187748 : r187762;
return r187763;
}




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)))