Average Error: 30.5 → 0.4
Time: 1.4m
Precision: 64
Internal Precision: 2432
\[\frac{1 - \cos x}{\sin x}\]
\[1 \cdot \frac{\sin x}{1 + \cos x}\]

Error

Bits error versus x

Target

Original30.5
Target0
Herbie0.4
\[\tan \left(\frac{x}{2}\right)\]

Derivation

  1. Initial program 30.5

    \[\frac{1 - \cos x}{\sin x}\]
  2. Using strategy rm
  3. Applied flip--30.8

    \[\leadsto \frac{\color{blue}{\frac{1 \cdot 1 - \cos x \cdot \cos x}{1 + \cos x}}}{\sin x}\]
  4. Applied simplify15.0

    \[\leadsto \frac{\frac{\color{blue}{\sin x \cdot \sin x}}{1 + \cos x}}{\sin x}\]
  5. Using strategy rm
  6. Applied *-un-lft-identity15.0

    \[\leadsto \frac{\frac{\sin x \cdot \sin x}{1 + \cos x}}{\color{blue}{1 \cdot \sin x}}\]
  7. Applied *-un-lft-identity15.0

    \[\leadsto \frac{\color{blue}{1 \cdot \frac{\sin x \cdot \sin x}{1 + \cos x}}}{1 \cdot \sin x}\]
  8. Applied times-frac15.0

    \[\leadsto \color{blue}{\frac{1}{1} \cdot \frac{\frac{\sin x \cdot \sin x}{1 + \cos x}}{\sin x}}\]
  9. Applied simplify15.0

    \[\leadsto \color{blue}{1} \cdot \frac{\frac{\sin x \cdot \sin x}{1 + \cos x}}{\sin x}\]
  10. Applied simplify0.4

    \[\leadsto 1 \cdot \color{blue}{\frac{\sin x}{1 + \cos x}}\]
  11. Removed slow pow expressions.

Runtime

Time bar (total: 1.4m)Debug logProfile

herbie shell --seed '#(1063027428 1192549564 1443466578 604016274 3637110559 1698629644)' 
(FPCore (x)
  :name "tanhf (example 3.4)"
  :herbie-expected 1

  :herbie-target
  (tan (/ x 2))

  (/ (- 1 (cos x)) (sin x)))