Average Error: 0.8 → 0.8
Time: 6.7m
Precision: 64
Internal Precision: 384
\[\left(\left(\left(\left(\left(\left(x1 \cdot x4\right) \cdot \left(\left(\left(\left(-x1\right) + x2\right) + x3\right) - x4\right) + x2 \cdot \left(\left(\left(x1 - x2\right) + x3\right) + x4\right)\right) + x3 \cdot \left(\left(\left(x1 + x2\right) - x3\right) + x4\right)\right) - \left(x2 \cdot x3\right) \cdot x4\right) - x1 \cdot x3\right) - x1 \cdot x2\right) - x4\]
\[\sqrt[3]{{\left(\left(\left(x1 \cdot x4\right) \cdot \left(\left(x2 + \left(x3 - x4\right)\right) + \left(-x1\right)\right) + \left(\left(x1 - x2 \cdot x4\right) - \left(\left(x3 - x4\right) - x2\right)\right) \cdot x3\right) + x2 \cdot \left(\left(x3 + x4\right) + \left(x1 - x2\right)\right)\right)}^{3}} - \left(\left(x2 + x3\right) \cdot x1 + x4\right)\]

Error

Bits error versus x1

Bits error versus x2

Bits error versus x3

Bits error versus x4

Derivation

  1. Initial program 0.8

    \[\left(\left(\left(\left(\left(\left(x1 \cdot x4\right) \cdot \left(\left(\left(\left(-x1\right) + x2\right) + x3\right) - x4\right) + x2 \cdot \left(\left(\left(x1 - x2\right) + x3\right) + x4\right)\right) + x3 \cdot \left(\left(\left(x1 + x2\right) - x3\right) + x4\right)\right) - \left(x2 \cdot x3\right) \cdot x4\right) - x1 \cdot x3\right) - x1 \cdot x2\right) - x4\]
  2. Using strategy rm
  3. Applied add-sqr-sqrt0.8

    \[\leadsto \left(\left(\left(\left(\left(\left(x1 \cdot x4\right) \cdot \left(\left(\left(\left(-x1\right) + x2\right) + x3\right) - x4\right) + x2 \cdot \left(\left(\left(x1 - x2\right) + x3\right) + x4\right)\right) + x3 \cdot \color{blue}{\left(\sqrt{\left(\left(x1 + x2\right) - x3\right) + x4} \cdot \sqrt{\left(\left(x1 + x2\right) - x3\right) + x4}\right)}\right) - \left(x2 \cdot x3\right) \cdot x4\right) - x1 \cdot x3\right) - x1 \cdot x2\right) - x4\]
  4. Applied associate-*r*0.8

    \[\leadsto \left(\left(\left(\left(\left(\left(x1 \cdot x4\right) \cdot \left(\left(\left(\left(-x1\right) + x2\right) + x3\right) - x4\right) + x2 \cdot \left(\left(\left(x1 - x2\right) + x3\right) + x4\right)\right) + \color{blue}{\left(x3 \cdot \sqrt{\left(\left(x1 + x2\right) - x3\right) + x4}\right) \cdot \sqrt{\left(\left(x1 + x2\right) - x3\right) + x4}}\right) - \left(x2 \cdot x3\right) \cdot x4\right) - x1 \cdot x3\right) - x1 \cdot x2\right) - x4\]
  5. Taylor expanded around inf 0.8

    \[\leadsto \left(\left(\left(\left(\left(\left(x1 \cdot x4\right) \cdot \left(\left(\left(\left(-x1\right) + x2\right) + x3\right) - x4\right) + x2 \cdot \left(\left(\left(x1 - x2\right) + x3\right) + x4\right)\right) + \left(x3 \cdot \sqrt{\left(\left(x1 + x2\right) - x3\right) + x4}\right) \cdot \sqrt{\left(\left(x1 + x2\right) - x3\right) + x4}\right) - \color{blue}{x2 \cdot \left(x4 \cdot x3\right)}\right) - x1 \cdot x3\right) - x1 \cdot x2\right) - x4\]
  6. Applied simplify0.8

    \[\leadsto \color{blue}{\left(\left(\left(x2 + \left(\left(-x1\right) + \left(x3 - x4\right)\right)\right) \cdot \left(x4 \cdot x1\right) + x3 \cdot \left(\left(x2 + x1\right) - \left(\left(x3 - x4\right) + x4 \cdot x2\right)\right)\right) + x2 \cdot \left(\left(x3 + x4\right) + \left(x1 - x2\right)\right)\right) - \left(\left(x2 + x3\right) \cdot x1 + x4\right)}\]
  7. Using strategy rm
  8. Applied add-cbrt-cube0.8

    \[\leadsto \color{blue}{\sqrt[3]{\left(\left(\left(\left(x2 + \left(\left(-x1\right) + \left(x3 - x4\right)\right)\right) \cdot \left(x4 \cdot x1\right) + x3 \cdot \left(\left(x2 + x1\right) - \left(\left(x3 - x4\right) + x4 \cdot x2\right)\right)\right) + x2 \cdot \left(\left(x3 + x4\right) + \left(x1 - x2\right)\right)\right) \cdot \left(\left(\left(x2 + \left(\left(-x1\right) + \left(x3 - x4\right)\right)\right) \cdot \left(x4 \cdot x1\right) + x3 \cdot \left(\left(x2 + x1\right) - \left(\left(x3 - x4\right) + x4 \cdot x2\right)\right)\right) + x2 \cdot \left(\left(x3 + x4\right) + \left(x1 - x2\right)\right)\right)\right) \cdot \left(\left(\left(x2 + \left(\left(-x1\right) + \left(x3 - x4\right)\right)\right) \cdot \left(x4 \cdot x1\right) + x3 \cdot \left(\left(x2 + x1\right) - \left(\left(x3 - x4\right) + x4 \cdot x2\right)\right)\right) + x2 \cdot \left(\left(x3 + x4\right) + \left(x1 - x2\right)\right)\right)}} - \left(\left(x2 + x3\right) \cdot x1 + x4\right)\]
  9. Applied simplify0.8

    \[\leadsto \sqrt[3]{\color{blue}{{\left(\left(\left(x1 \cdot x4\right) \cdot \left(\left(x2 + \left(x3 - x4\right)\right) + \left(-x1\right)\right) + \left(\left(x1 - x2 \cdot x4\right) - \left(\left(x3 - x4\right) - x2\right)\right) \cdot x3\right) + x2 \cdot \left(\left(x3 + x4\right) + \left(x1 - x2\right)\right)\right)}^{3}}} - \left(\left(x2 + x3\right) \cdot x1 + x4\right)\]

Runtime

Time bar (total: 6.7m)Debug log

herbie shell --seed '#(1743936871 1855164119 3668777427 1254258049 132811564 1366975197)' 
(FPCore (x1 x2 x3 x4)
  :name "kepler1"
  :pre (and (<= 4 x1 6.36) (<= 4 x2 6.36) (<= 4 x3 6.36) (<= 4 x4 6.36))
  (- (- (- (- (+ (+ (* (* x1 x4) (- (+ (+ (- x1) x2) x3) x4)) (* x2 (+ (+ (- x1 x2) x3) x4))) (* x3 (+ (- (+ x1 x2) x3) x4))) (* (* x2 x3) x4)) (* x1 x3)) (* x1 x2)) x4))