Average Error: 37.4 → 14.0
Time: 2.2m
Precision: 64
Internal Precision: 2368
\[\tan \left(x + \varepsilon\right) - \tan x\]
\[\begin{array}{l} \mathbf{if}\;(\left(\varepsilon \cdot x\right) \cdot \left((\left(\varepsilon \cdot x\right) \cdot \varepsilon + \varepsilon)_*\right) + \varepsilon)_* \le -8.53710463573885 \cdot 10^{-09}:\\ \;\;\;\;(\left(\frac{\tan \varepsilon + \tan x}{1 - \left(\tan \varepsilon \cdot \tan x\right) \cdot \left(\tan \varepsilon \cdot \tan x\right)}\right) \cdot \left(\tan \varepsilon \cdot \tan x + 1\right) + \left(-\tan x\right))_*\\ \mathbf{if}\;(\left(\varepsilon \cdot x\right) \cdot \left((\left(\varepsilon \cdot x\right) \cdot \varepsilon + \varepsilon)_*\right) + \varepsilon)_* \le 1.1108439280395142 \cdot 10^{-47}:\\ \;\;\;\;(\left(\varepsilon \cdot x\right) \cdot \left((\left(\varepsilon \cdot x\right) \cdot \varepsilon + \varepsilon)_*\right) + \varepsilon)_*\\ \mathbf{else}:\\ \;\;\;\;\frac{(\left(\tan \varepsilon + \tan x\right) \cdot \left(\cos x\right) + \left((\left(\tan x \cdot \sin x\right) \cdot \left(\tan \varepsilon\right) + \left(-\sin x\right))_*\right))_*}{(\left(-\cos x\right) \cdot \left(\tan \varepsilon \cdot \tan x\right) + \left(\cos x\right))_*}\\ \end{array}\]

Error

Bits error versus x

Bits error versus eps

Target

Original37.4
Target15.3
Herbie14.0
\[\frac{\sin \varepsilon}{\cos x \cdot \cos \left(x + \varepsilon\right)}\]

Derivation

  1. Split input into 3 regimes
  2. if (fma (* x eps) (fma (* x eps) eps eps) eps) < -8.53710463573885e-09

    1. Initial program 33.9

      \[\tan \left(x + \varepsilon\right) - \tan x\]
    2. Using strategy rm
    3. Applied tan-sum7.8

      \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon}} - \tan x\]
    4. Using strategy rm
    5. Applied flip--7.9

      \[\leadsto \frac{\tan x + \tan \varepsilon}{\color{blue}{\frac{1 \cdot 1 - \left(\tan x \cdot \tan \varepsilon\right) \cdot \left(\tan x \cdot \tan \varepsilon\right)}{1 + \tan x \cdot \tan \varepsilon}}} - \tan x\]
    6. Applied associate-/r/7.9

      \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 \cdot 1 - \left(\tan x \cdot \tan \varepsilon\right) \cdot \left(\tan x \cdot \tan \varepsilon\right)} \cdot \left(1 + \tan x \cdot \tan \varepsilon\right)} - \tan x\]
    7. Applied fma-neg7.9

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

    if -8.53710463573885e-09 < (fma (* x eps) (fma (* x eps) eps eps) eps) < 1.1108439280395142e-47

    1. Initial program 43.3

      \[\tan \left(x + \varepsilon\right) - \tan x\]
    2. Taylor expanded around 0 23.9

      \[\leadsto \color{blue}{\varepsilon + \left({\varepsilon}^{3} \cdot {x}^{2} + {\varepsilon}^{2} \cdot x\right)}\]
    3. Applied simplify22.6

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

    if 1.1108439280395142e-47 < (fma (* x eps) (fma (* x eps) eps eps) eps)

    1. Initial program 33.4

      \[\tan \left(x + \varepsilon\right) - \tan x\]
    2. Using strategy rm
    3. Applied tan-sum9.2

      \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon}} - \tan x\]
    4. Using strategy rm
    5. Applied add-cube-cbrt9.3

      \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \color{blue}{\left(\sqrt[3]{\tan x \cdot \tan \varepsilon} \cdot \sqrt[3]{\tan x \cdot \tan \varepsilon}\right) \cdot \sqrt[3]{\tan x \cdot \tan \varepsilon}}} - \tan x\]
    6. Using strategy rm
    7. Applied tan-quot9.4

      \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \left(\sqrt[3]{\tan x \cdot \tan \varepsilon} \cdot \sqrt[3]{\tan x \cdot \tan \varepsilon}\right) \cdot \sqrt[3]{\tan x \cdot \tan \varepsilon}} - \color{blue}{\frac{\sin x}{\cos x}}\]
    8. Applied frac-sub9.4

      \[\leadsto \color{blue}{\frac{\left(\tan x + \tan \varepsilon\right) \cdot \cos x - \left(1 - \left(\sqrt[3]{\tan x \cdot \tan \varepsilon} \cdot \sqrt[3]{\tan x \cdot \tan \varepsilon}\right) \cdot \sqrt[3]{\tan x \cdot \tan \varepsilon}\right) \cdot \sin x}{\left(1 - \left(\sqrt[3]{\tan x \cdot \tan \varepsilon} \cdot \sqrt[3]{\tan x \cdot \tan \varepsilon}\right) \cdot \sqrt[3]{\tan x \cdot \tan \varepsilon}\right) \cdot \cos x}}\]
    9. Applied simplify9.4

      \[\leadsto \frac{\color{blue}{(\left(\tan \varepsilon + \tan x\right) \cdot \left(\cos x\right) + \left((\left(\tan x \cdot \sin x\right) \cdot \left(\tan \varepsilon\right) + \left(-\sin x\right))_*\right))_*}}{\left(1 - \left(\sqrt[3]{\tan x \cdot \tan \varepsilon} \cdot \sqrt[3]{\tan x \cdot \tan \varepsilon}\right) \cdot \sqrt[3]{\tan x \cdot \tan \varepsilon}\right) \cdot \cos x}\]
    10. Applied simplify9.2

      \[\leadsto \frac{(\left(\tan \varepsilon + \tan x\right) \cdot \left(\cos x\right) + \left((\left(\tan x \cdot \sin x\right) \cdot \left(\tan \varepsilon\right) + \left(-\sin x\right))_*\right))_*}{\color{blue}{(\left(-\cos x\right) \cdot \left(\tan x \cdot \tan \varepsilon\right) + \left(\cos x\right))_*}}\]
  3. Recombined 3 regimes into one program.
  4. Applied simplify14.0

    \[\leadsto \color{blue}{\begin{array}{l} \mathbf{if}\;(\left(\varepsilon \cdot x\right) \cdot \left((\left(\varepsilon \cdot x\right) \cdot \varepsilon + \varepsilon)_*\right) + \varepsilon)_* \le -8.53710463573885 \cdot 10^{-09}:\\ \;\;\;\;(\left(\frac{\tan \varepsilon + \tan x}{1 - \left(\tan \varepsilon \cdot \tan x\right) \cdot \left(\tan \varepsilon \cdot \tan x\right)}\right) \cdot \left(\tan \varepsilon \cdot \tan x + 1\right) + \left(-\tan x\right))_*\\ \mathbf{if}\;(\left(\varepsilon \cdot x\right) \cdot \left((\left(\varepsilon \cdot x\right) \cdot \varepsilon + \varepsilon)_*\right) + \varepsilon)_* \le 1.1108439280395142 \cdot 10^{-47}:\\ \;\;\;\;(\left(\varepsilon \cdot x\right) \cdot \left((\left(\varepsilon \cdot x\right) \cdot \varepsilon + \varepsilon)_*\right) + \varepsilon)_*\\ \mathbf{else}:\\ \;\;\;\;\frac{(\left(\tan \varepsilon + \tan x\right) \cdot \left(\cos x\right) + \left((\left(\tan x \cdot \sin x\right) \cdot \left(\tan \varepsilon\right) + \left(-\sin x\right))_*\right))_*}{(\left(-\cos x\right) \cdot \left(\tan \varepsilon \cdot \tan x\right) + \left(\cos x\right))_*}\\ \end{array}}\]

Runtime

Time bar (total: 2.2m)Debug logProfile

herbie shell --seed '#(1071852389 864846987 1238109217 3425890003 4124793586 650694553)' +o rules:numerics
(FPCore (x eps)
  :name "2tan (problem 3.3.2)"

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

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