Average Error: 52.2 → 0.1
Time: 19.0s
Precision: 64
Internal Precision: 2432
\[\log \left(x + \sqrt{x \cdot x + 1}\right)\]
↓
\[\begin{array}{l} \mathbf{if}\;x \le -1.1836965105960906:\\ \;\;\;\;\log \left(\frac{\frac{\frac{1}{8}}{x}}{x \cdot x} - \frac{\frac{1}{2}}{x}\right)\\ \mathbf{if}\;x \le 0.007924711946220716:\\ \;\;\;\;\left(\frac{3}{40} \cdot {x}^{5} + x\right) - \frac{1}{6} \cdot {x}^{3}\\ \mathbf{if}\;x \le +\infty:\\ \;\;\;\;\log \left((\left(\sqrt{\sqrt{1^2 + x^2}^*}\right) \cdot \left(\sqrt{\sqrt{1^2 + x^2}^*}\right) + x)_*\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left((\left(\sqrt{\sqrt{1^2 + x^2}^*}\right) \cdot \left(\sqrt{\sqrt{1^2 + x^2}^*}\right) + x)_*\right)\\ \end{array}\]

Error

Bits error versus x

Target

Original52.2
Target44.0
Herbie0.1
\[\begin{array}{l} \mathbf{if}\;x \lt 0:\\ \;\;\;\;\log \left(\frac{-1}{x - \sqrt{x \cdot x + 1}}\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(x + \sqrt{x \cdot x + 1}\right)\\ \end{array}\]

Derivation

  1. Split input into 3 regimes

  2. if x < -1.1836965105960906

    1. Initial program 61.7

      \[\log \left(x + \sqrt{x \cdot x + 1}\right)\]

    2. Applied simplify60.9

      \[\leadsto \color{blue}{\log \left(\sqrt{1^2 + x^2}^* + x\right)}\]

    3. Taylor expanded around -inf 61.1

      \[\leadsto \log \left(\color{blue}{\left(\frac{1}{8} \cdot \frac{1}{{x}^{3}} - \left(\frac{1}{2} \cdot \frac{1}{x} + x\right)\right)} + x\right)\]

    4. Applied simplify0.2

      \[\leadsto \color{blue}{\log \left(\frac{\frac{\frac{1}{8}}{x}}{x \cdot x} - \frac{\frac{1}{2}}{x}\right)}\]

    if -1.1836965105960906 < x < 0.007924711946220716

    1. Initial program 58.7

      \[\log \left(x + \sqrt{x \cdot x + 1}\right)\]

    2. Applied simplify58.7

      \[\leadsto \color{blue}{\log \left(\sqrt{1^2 + x^2}^* + x\right)}\]

    3. Taylor expanded around 0 0.1

      \[\leadsto \color{blue}{\left(\frac{3}{40} \cdot {x}^{5} + x\right) - \frac{1}{6} \cdot {x}^{3}}\]

    if 0.007924711946220716 < x

    1. Initial program 29.7

      \[\log \left(x + \sqrt{x \cdot x + 1}\right)\]

    2. Applied simplify0.1

      \[\leadsto \color{blue}{\log \left(\sqrt{1^2 + x^2}^* + x\right)}\]
    3. Using strategy rm

    4. Applied add-sqr-sqrt0.2

      \[\leadsto \log \left(\color{blue}{\sqrt{\sqrt{1^2 + x^2}^*} \cdot \sqrt{\sqrt{1^2 + x^2}^*}} + x\right)\]

    5. Applied fma-def0.2

      \[\leadsto \log \color{blue}{\left((\left(\sqrt{\sqrt{1^2 + x^2}^*}\right) \cdot \left(\sqrt{\sqrt{1^2 + x^2}^*}\right) + x)_*\right)}\]
  3. Recombined 3 regimes into one program.

Runtime

Time bar (total: 19.0s)Debug logProfile

herbie shell --seed '#(1070131407 1246090267 3027482374 2150728003 2026520792 2347815650)' +o rules:numerics
(FPCore (x)
  :name "Hyperbolic arcsine"

  :herbie-target
  (if (< x 0) (log (/ -1 (- x (sqrt (+ (* x x) 1))))) (log (+ x (sqrt (+ (* x x) 1)))))

  (log (+ x (sqrt (+ (* x x) 1)))))