Average Error: 37.4 → 15.4
Time: 32.6s
Precision: 64
\[\tan \left(x + \varepsilon\right) - \tan x\]
\[\begin{array}{l} \mathbf{if}\;\varepsilon \le -8.29565067036897 \cdot 10^{-18}:\\ \;\;\;\;\frac{\tan \varepsilon + \tan x}{\log \left(e^{1 - \tan x \cdot \tan \varepsilon}\right)} - \tan x\\ \mathbf{elif}\;\varepsilon \le 3.143523747535153 \cdot 10^{-69}:\\ \;\;\;\;x \cdot \left(\varepsilon \cdot \left(x + \varepsilon\right)\right) + \varepsilon\\ \mathbf{else}:\\ \;\;\;\;\frac{\left(\tan \varepsilon + \tan x\right) \cdot \cos x - \sin x \cdot \left(1 - \frac{\tan x \cdot \sin \varepsilon}{\cos \varepsilon}\right)}{\left(1 - \frac{\tan x \cdot \sin \varepsilon}{\cos \varepsilon}\right) \cdot \cos x}\\ \end{array}\]
\tan \left(x + \varepsilon\right) - \tan x
\begin{array}{l}
\mathbf{if}\;\varepsilon \le -8.29565067036897 \cdot 10^{-18}:\\
\;\;\;\;\frac{\tan \varepsilon + \tan x}{\log \left(e^{1 - \tan x \cdot \tan \varepsilon}\right)} - \tan x\\

\mathbf{elif}\;\varepsilon \le 3.143523747535153 \cdot 10^{-69}:\\
\;\;\;\;x \cdot \left(\varepsilon \cdot \left(x + \varepsilon\right)\right) + \varepsilon\\

\mathbf{else}:\\
\;\;\;\;\frac{\left(\tan \varepsilon + \tan x\right) \cdot \cos x - \sin x \cdot \left(1 - \frac{\tan x \cdot \sin \varepsilon}{\cos \varepsilon}\right)}{\left(1 - \frac{\tan x \cdot \sin \varepsilon}{\cos \varepsilon}\right) \cdot \cos x}\\

\end{array}
double f(double x, double eps) {
        double r3333317 = x;
        double r3333318 = eps;
        double r3333319 = r3333317 + r3333318;
        double r3333320 = tan(r3333319);
        double r3333321 = tan(r3333317);
        double r3333322 = r3333320 - r3333321;
        return r3333322;
}

double f(double x, double eps) {
        double r3333323 = eps;
        double r3333324 = -8.29565067036897e-18;
        bool r3333325 = r3333323 <= r3333324;
        double r3333326 = tan(r3333323);
        double r3333327 = x;
        double r3333328 = tan(r3333327);
        double r3333329 = r3333326 + r3333328;
        double r3333330 = 1.0;
        double r3333331 = r3333328 * r3333326;
        double r3333332 = r3333330 - r3333331;
        double r3333333 = exp(r3333332);
        double r3333334 = log(r3333333);
        double r3333335 = r3333329 / r3333334;
        double r3333336 = r3333335 - r3333328;
        double r3333337 = 3.143523747535153e-69;
        bool r3333338 = r3333323 <= r3333337;
        double r3333339 = r3333327 + r3333323;
        double r3333340 = r3333323 * r3333339;
        double r3333341 = r3333327 * r3333340;
        double r3333342 = r3333341 + r3333323;
        double r3333343 = cos(r3333327);
        double r3333344 = r3333329 * r3333343;
        double r3333345 = sin(r3333327);
        double r3333346 = sin(r3333323);
        double r3333347 = r3333328 * r3333346;
        double r3333348 = cos(r3333323);
        double r3333349 = r3333347 / r3333348;
        double r3333350 = r3333330 - r3333349;
        double r3333351 = r3333345 * r3333350;
        double r3333352 = r3333344 - r3333351;
        double r3333353 = r3333350 * r3333343;
        double r3333354 = r3333352 / r3333353;
        double r3333355 = r3333338 ? r3333342 : r3333354;
        double r3333356 = r3333325 ? r3333336 : r3333355;
        return r3333356;
}

Error

Bits error versus x

Bits error versus eps

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Target

Original37.4
Target15.3
Herbie15.4
\[\frac{\sin \varepsilon}{\cos x \cdot \cos \left(x + \varepsilon\right)}\]

Derivation

  1. Split input into 3 regimes
  2. if eps < -8.29565067036897e-18

    1. Initial program 30.3

      \[\tan \left(x + \varepsilon\right) - \tan x\]
    2. Using strategy rm
    3. Applied tan-sum0.9

      \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon}} - \tan x\]
    4. Using strategy rm
    5. Applied add-log-exp1.0

      \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \color{blue}{\log \left(e^{\tan x \cdot \tan \varepsilon}\right)}} - \tan x\]
    6. Applied add-log-exp1.0

      \[\leadsto \frac{\tan x + \tan \varepsilon}{\color{blue}{\log \left(e^{1}\right)} - \log \left(e^{\tan x \cdot \tan \varepsilon}\right)} - \tan x\]
    7. Applied diff-log1.0

      \[\leadsto \frac{\tan x + \tan \varepsilon}{\color{blue}{\log \left(\frac{e^{1}}{e^{\tan x \cdot \tan \varepsilon}}\right)}} - \tan x\]
    8. Simplified1.0

      \[\leadsto \frac{\tan x + \tan \varepsilon}{\log \color{blue}{\left(e^{1 - \tan \varepsilon \cdot \tan x}\right)}} - \tan x\]

    if -8.29565067036897e-18 < eps < 3.143523747535153e-69

    1. Initial program 46.7

      \[\tan \left(x + \varepsilon\right) - \tan x\]
    2. Taylor expanded around 0 31.2

      \[\leadsto \color{blue}{x \cdot {\varepsilon}^{2} + \left(\varepsilon + {x}^{2} \cdot \varepsilon\right)}\]
    3. Simplified31.1

      \[\leadsto \color{blue}{\varepsilon + \left(\varepsilon \cdot \left(x + \varepsilon\right)\right) \cdot x}\]

    if 3.143523747535153e-69 < eps

    1. Initial program 30.5

      \[\tan \left(x + \varepsilon\right) - \tan x\]
    2. Using strategy rm
    3. Applied tan-sum5.9

      \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon}} - \tan x\]
    4. Using strategy rm
    5. Applied tan-quot5.9

      \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \color{blue}{\frac{\sin \varepsilon}{\cos \varepsilon}}} - \tan x\]
    6. Applied associate-*r/5.9

      \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \color{blue}{\frac{\tan x \cdot \sin \varepsilon}{\cos \varepsilon}}} - \tan x\]
    7. Using strategy rm
    8. Applied tan-quot5.9

      \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \frac{\tan x \cdot \sin \varepsilon}{\cos \varepsilon}} - \color{blue}{\frac{\sin x}{\cos x}}\]
    9. Applied frac-sub5.9

      \[\leadsto \color{blue}{\frac{\left(\tan x + \tan \varepsilon\right) \cdot \cos x - \left(1 - \frac{\tan x \cdot \sin \varepsilon}{\cos \varepsilon}\right) \cdot \sin x}{\left(1 - \frac{\tan x \cdot \sin \varepsilon}{\cos \varepsilon}\right) \cdot \cos x}}\]
  3. Recombined 3 regimes into one program.
  4. Final simplification15.4

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \le -8.29565067036897 \cdot 10^{-18}:\\ \;\;\;\;\frac{\tan \varepsilon + \tan x}{\log \left(e^{1 - \tan x \cdot \tan \varepsilon}\right)} - \tan x\\ \mathbf{elif}\;\varepsilon \le 3.143523747535153 \cdot 10^{-69}:\\ \;\;\;\;x \cdot \left(\varepsilon \cdot \left(x + \varepsilon\right)\right) + \varepsilon\\ \mathbf{else}:\\ \;\;\;\;\frac{\left(\tan \varepsilon + \tan x\right) \cdot \cos x - \sin x \cdot \left(1 - \frac{\tan x \cdot \sin \varepsilon}{\cos \varepsilon}\right)}{\left(1 - \frac{\tan x \cdot \sin \varepsilon}{\cos \varepsilon}\right) \cdot \cos x}\\ \end{array}\]

Reproduce

herbie shell --seed 2019139 
(FPCore (x eps)
  :name "2tan (problem 3.3.2)"

  :herbie-target
  (/ (sin eps) (* (cos x) (cos (+ x eps))))

  (- (tan (+ x eps)) (tan x)))