Average Error: 0.3 → 0.3
Time: 53.2s
Precision: 64
Internal Precision: 128
\[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t\]
\[\log z + \left(\log \left(\sqrt[3]{x + y} \cdot \sqrt[3]{x + y}\right) + \left(\left(a - 0.5\right) \cdot \log t + \left(\log \left(\sqrt[3]{x + y}\right) - t\right)\right)\right)\]

Error

Bits error versus x

Bits error versus y

Bits error versus z

Bits error versus t

Bits error versus a

Derivation

  1. Initial program 0.3

    \[\left(\left(\log \left(x + y\right) + \log z\right) - t\right) + \left(a - 0.5\right) \cdot \log t\]
  2. Simplified0.3

    \[\leadsto \color{blue}{\left(\log \left(y + x\right) - t\right) + (\left(a - 0.5\right) \cdot \left(\log t\right) + \left(\log z\right))_*}\]
  3. Using strategy rm
  4. Applied fma-udef0.3

    \[\leadsto \left(\log \left(y + x\right) - t\right) + \color{blue}{\left(\left(a - 0.5\right) \cdot \log t + \log z\right)}\]
  5. Applied associate-+r+0.3

    \[\leadsto \color{blue}{\left(\left(\log \left(y + x\right) - t\right) + \left(a - 0.5\right) \cdot \log t\right) + \log z}\]
  6. Using strategy rm
  7. Applied add-cube-cbrt0.3

    \[\leadsto \left(\left(\log \color{blue}{\left(\left(\sqrt[3]{y + x} \cdot \sqrt[3]{y + x}\right) \cdot \sqrt[3]{y + x}\right)} - t\right) + \left(a - 0.5\right) \cdot \log t\right) + \log z\]
  8. Applied log-prod0.3

    \[\leadsto \left(\left(\color{blue}{\left(\log \left(\sqrt[3]{y + x} \cdot \sqrt[3]{y + x}\right) + \log \left(\sqrt[3]{y + x}\right)\right)} - t\right) + \left(a - 0.5\right) \cdot \log t\right) + \log z\]
  9. Applied associate--l+0.3

    \[\leadsto \left(\color{blue}{\left(\log \left(\sqrt[3]{y + x} \cdot \sqrt[3]{y + x}\right) + \left(\log \left(\sqrt[3]{y + x}\right) - t\right)\right)} + \left(a - 0.5\right) \cdot \log t\right) + \log z\]
  10. Applied associate-+l+0.3

    \[\leadsto \color{blue}{\left(\log \left(\sqrt[3]{y + x} \cdot \sqrt[3]{y + x}\right) + \left(\left(\log \left(\sqrt[3]{y + x}\right) - t\right) + \left(a - 0.5\right) \cdot \log t\right)\right)} + \log z\]
  11. Final simplification0.3

    \[\leadsto \log z + \left(\log \left(\sqrt[3]{x + y} \cdot \sqrt[3]{x + y}\right) + \left(\left(a - 0.5\right) \cdot \log t + \left(\log \left(\sqrt[3]{x + y}\right) - t\right)\right)\right)\]

Reproduce

herbie shell --seed 2019094 +o rules:numerics
(FPCore (x y z t a)
  :name "Numeric.SpecFunctions:logGammaL from math-functions-0.1.5.2"
  (+ (- (+ (log (+ x y)) (log z)) t) (* (- a 0.5) (log t))))