Average Error: 30.6 → 16.6
Time: 3.7s
Precision: 64
Internal Precision: 576
\[\log \left(\sqrt{re \cdot re + im \cdot im}\right)\]
\[\begin{array}{l} \mathbf{if}\;re \le -8.909366589068526 \cdot 10^{+70}:\\ \;\;\;\;\log \left(-re\right)\\ \mathbf{elif}\;re \le 1.612196108127751 \cdot 10^{+139}:\\ \;\;\;\;\log \left(\sqrt{im \cdot im + re \cdot re}\right)\\ \mathbf{else}:\\ \;\;\;\;\log re\\ \end{array}\]

Error

Bits error versus re

Bits error versus im

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Derivation

  1. Split input into 3 regimes
  2. if re < -8.909366589068526e+70

    1. Initial program 45.7

      \[\log \left(\sqrt{re \cdot re + im \cdot im}\right)\]
    2. Taylor expanded around -inf 10.3

      \[\leadsto \log \color{blue}{\left(-1 \cdot re\right)}\]
    3. Simplified10.3

      \[\leadsto \log \color{blue}{\left(-re\right)}\]

    if -8.909366589068526e+70 < re < 1.612196108127751e+139

    1. Initial program 20.6

      \[\log \left(\sqrt{re \cdot re + im \cdot im}\right)\]

    if 1.612196108127751e+139 < re

    1. Initial program 57.6

      \[\log \left(\sqrt{re \cdot re + im \cdot im}\right)\]
    2. Taylor expanded around inf 6.3

      \[\leadsto \log \color{blue}{re}\]
  3. Recombined 3 regimes into one program.
  4. Final simplification16.6

    \[\leadsto \begin{array}{l} \mathbf{if}\;re \le -8.909366589068526 \cdot 10^{+70}:\\ \;\;\;\;\log \left(-re\right)\\ \mathbf{elif}\;re \le 1.612196108127751 \cdot 10^{+139}:\\ \;\;\;\;\log \left(\sqrt{im \cdot im + re \cdot re}\right)\\ \mathbf{else}:\\ \;\;\;\;\log re\\ \end{array}\]

Runtime

Time bar (total: 3.7s)Debug logProfile

herbie shell --seed 2018220 
(FPCore (re im)
  :name "math.log/1 on complex, real part"
  (log (sqrt (+ (* re re) (* im im)))))