Average Error: 42.0 → 24.5
Time: 58.2s
Precision: 64
Ground Truth: 128
\[\tan \left(x + \varepsilon\right) - \tan x\]
\[\begin{array}{l} \mathbf{if}\;\varepsilon \le -1.1324884610140404 \cdot 10^{-37}:\\ \;\;\;\;\frac{\cos x - {\left(\sqrt[3]{\cot \left(x + \varepsilon\right)} \cdot \sqrt[3]{\sin x}\right)}^3}{\cot \left(x + \varepsilon\right) \cdot \cos x}\\ \mathbf{if}\;\varepsilon \le -8.343087553984244 \cdot 10^{-186}:\\ \;\;\;\;\frac{\left(\sin x \cdot \varepsilon + \left(\frac{{\varepsilon}^{3} \cdot {\left(\cos x\right)}^{4}}{{\left(\sin x\right)}^{3}} + \left(\frac{\varepsilon \cdot {\left(\cos x\right)}^2}{\sin x} + \left(\frac{1}{3} \cdot \left(\sin x \cdot {\varepsilon}^{3}\right) + \frac{4}{3} \cdot \frac{{\varepsilon}^{3} \cdot {\left(\cos x\right)}^2}{\sin x}\right)\right)\right)\right) - \left(\frac{{\varepsilon}^2 \cdot {\left(\cos x\right)}^{3}}{{\left(\sin x\right)}^2} + {\varepsilon}^2 \cdot \cos x\right)}{\cot \left(x + \varepsilon\right) \cdot \cos x}\\ \mathbf{if}\;\varepsilon \le -1.4036887096279737 \cdot 10^{-262}:\\ \;\;\;\;\left(\varepsilon + {\varepsilon}^{4} \cdot {x}^3\right) + \left(x \cdot x\right) \cdot {\varepsilon}^3\\ \mathbf{if}\;\varepsilon \le 4.0170806835946265 \cdot 10^{-42}:\\ \;\;\;\;\frac{\left(\sin x \cdot \varepsilon + \left(\frac{{\varepsilon}^{3} \cdot {\left(\cos x\right)}^{4}}{{\left(\sin x\right)}^{3}} + \left(\frac{\varepsilon \cdot {\left(\cos x\right)}^2}{\sin x} + \left(\frac{1}{3} \cdot \left(\sin x \cdot {\varepsilon}^{3}\right) + \frac{4}{3} \cdot \frac{{\varepsilon}^{3} \cdot {\left(\cos x\right)}^2}{\sin x}\right)\right)\right)\right) - \left(\frac{{\varepsilon}^2 \cdot {\left(\cos x\right)}^{3}}{{\left(\sin x\right)}^2} + {\varepsilon}^2 \cdot \cos x\right)}{\cot \left(x + \varepsilon\right) \cdot \cos x}\\ \mathbf{else}:\\ \;\;\;\;\frac{\cos x - {\left(\sqrt[3]{\cot \left(x + \varepsilon\right)} \cdot \sqrt[3]{\sin x}\right)}^3}{\cot \left(x + \varepsilon\right) \cdot \cos x}\\ \end{array}\]

Error

Bits error versus x

Bits error versus eps

Target

Original42.0
Comparison21.0
Herbie24.5
\[ \frac{\sin \varepsilon}{\cos x \cdot \cos \left(x + \varepsilon\right)} \]

Derivation

  1. Split input into 3 regimes.
  2. if eps < -1.1324884610140404e-37 or 4.0170806835946265e-42 < eps

    1. Initial program 29.6

      \[\tan \left(x + \varepsilon\right) - \tan x\]
    2. Using strategy rm
    3. Applied tan-quot 29.5

      \[\leadsto \tan \left(x + \varepsilon\right) - \color{blue}{\frac{\sin x}{\cos x}}\]
    4. Applied tan-cotan 29.5

      \[\leadsto \color{blue}{\frac{1}{\cot \left(x + \varepsilon\right)}} - \frac{\sin x}{\cos x}\]
    5. Applied frac-sub 29.4

      \[\leadsto \color{blue}{\frac{1 \cdot \cos x - \cot \left(x + \varepsilon\right) \cdot \sin x}{\cot \left(x + \varepsilon\right) \cdot \cos x}}\]
    6. Applied simplify 29.4

      \[\leadsto \frac{\color{blue}{\cos x - \cot \left(x + \varepsilon\right) \cdot \sin x}}{\cot \left(x + \varepsilon\right) \cdot \cos x}\]
    7. Using strategy rm
    8. Applied add-cube-cbrt 29.3

      \[\leadsto \frac{\cos x - \cot \left(x + \varepsilon\right) \cdot \color{blue}{{\left(\sqrt[3]{\sin x}\right)}^3}}{\cot \left(x + \varepsilon\right) \cdot \cos x}\]
    9. Applied add-cube-cbrt 29.3

      \[\leadsto \frac{\cos x - \color{blue}{{\left(\sqrt[3]{\cot \left(x + \varepsilon\right)}\right)}^3} \cdot {\left(\sqrt[3]{\sin x}\right)}^3}{\cot \left(x + \varepsilon\right) \cdot \cos x}\]
    10. Applied cube-unprod 29.3

      \[\leadsto \frac{\cos x - \color{blue}{{\left(\sqrt[3]{\cot \left(x + \varepsilon\right)} \cdot \sqrt[3]{\sin x}\right)}^3}}{\cot \left(x + \varepsilon\right) \cdot \cos x}\]

    if -1.1324884610140404e-37 < eps < -8.343087553984244e-186 or -1.4036887096279737e-262 < eps < 4.0170806835946265e-42

    1. Initial program 59.9

      \[\tan \left(x + \varepsilon\right) - \tan x\]
    2. Using strategy rm
    3. Applied tan-quot 60.2

      \[\leadsto \tan \left(x + \varepsilon\right) - \color{blue}{\frac{\sin x}{\cos x}}\]
    4. Applied tan-cotan 60.3

      \[\leadsto \color{blue}{\frac{1}{\cot \left(x + \varepsilon\right)}} - \frac{\sin x}{\cos x}\]
    5. Applied frac-sub 60.3

      \[\leadsto \color{blue}{\frac{1 \cdot \cos x - \cot \left(x + \varepsilon\right) \cdot \sin x}{\cot \left(x + \varepsilon\right) \cdot \cos x}}\]
    6. Applied simplify 60.3

      \[\leadsto \frac{\color{blue}{\cos x - \cot \left(x + \varepsilon\right) \cdot \sin x}}{\cot \left(x + \varepsilon\right) \cdot \cos x}\]
    7. Using strategy rm
    8. Applied add-cbrt-cube 60.3

      \[\leadsto \frac{\color{blue}{\sqrt[3]{{\left(\cos x - \cot \left(x + \varepsilon\right) \cdot \sin x\right)}^3}}}{\cot \left(x + \varepsilon\right) \cdot \cos x}\]
    9. Applied taylor 17.2

      \[\leadsto \frac{\left(\sin x \cdot \varepsilon + \left(\frac{{\varepsilon}^{3} \cdot {\left(\cos x\right)}^{4}}{{\left(\sin x\right)}^{3}} + \left(\frac{\varepsilon \cdot {\left(\cos x\right)}^2}{\sin x} + \left(\frac{1}{3} \cdot \left(\sin x \cdot {\varepsilon}^{3}\right) + \frac{4}{3} \cdot \frac{{\varepsilon}^{3} \cdot {\left(\cos x\right)}^2}{\sin x}\right)\right)\right)\right) - \left(\frac{{\varepsilon}^2 \cdot {\left(\cos x\right)}^{3}}{{\left(\sin x\right)}^2} + {\varepsilon}^2 \cdot \cos x\right)}{\cot \left(x + \varepsilon\right) \cdot \cos x}\]
    10. Taylor expanded around 0 17.2

      \[\leadsto \frac{\color{blue}{\left(\sin x \cdot \varepsilon + \left(\frac{{\varepsilon}^{3} \cdot {\left(\cos x\right)}^{4}}{{\left(\sin x\right)}^{3}} + \left(\frac{\varepsilon \cdot {\left(\cos x\right)}^2}{\sin x} + \left(\frac{1}{3} \cdot \left(\sin x \cdot {\varepsilon}^{3}\right) + \frac{4}{3} \cdot \frac{{\varepsilon}^{3} \cdot {\left(\cos x\right)}^2}{\sin x}\right)\right)\right)\right) - \left(\frac{{\varepsilon}^2 \cdot {\left(\cos x\right)}^{3}}{{\left(\sin x\right)}^2} + {\varepsilon}^2 \cdot \cos x\right)}}{\cot \left(x + \varepsilon\right) \cdot \cos x}\]

    if -8.343087553984244e-186 < eps < -1.4036887096279737e-262

    1. Initial program 51.0

      \[\tan \left(x + \varepsilon\right) - \tan x\]
    2. Applied taylor 23.0

      \[\leadsto \varepsilon + \left({\varepsilon}^{4} \cdot {x}^{3} + {\varepsilon}^{3} \cdot {x}^2\right)\]
    3. Taylor expanded around 0 23.0

      \[\leadsto \color{blue}{\varepsilon + \left({\varepsilon}^{4} \cdot {x}^{3} + {\varepsilon}^{3} \cdot {x}^2\right)}\]
    4. Applied simplify 23.0

      \[\leadsto \color{blue}{\left(\varepsilon + {\varepsilon}^{4} \cdot {x}^3\right) + \left(x \cdot x\right) \cdot {\varepsilon}^3}\]
  3. Recombined 3 regimes into one program.
  4. Removed slow pow expressions

Runtime

Total time: 58.2s Debug log

Please include this information when filing a bug report:

herbie --seed '#(3916392738 3454683258 2683473460 599201605 346020274 3845347111)'
(FPCore (x eps)
  :name "NMSE problem 3.3.2"
  :herbie-expected 28

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

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