Average Error: 31.1 → 17.3
Time: 3.6s
Precision: 64
Internal Precision: 128
\[\log \left(\sqrt{re \cdot re + im \cdot im}\right)\]
\[\begin{array}{l} \mathbf{if}\;re \le -6.1157351543722565 \cdot 10^{+62}:\\ \;\;\;\;\log \left(-re\right)\\ \mathbf{elif}\;re \le 2.194524025777904 \cdot 10^{+126}:\\ \;\;\;\;\log \left(\sqrt{im \cdot im + re \cdot re}\right)\\ \mathbf{else}:\\ \;\;\;\;\log re\\ \end{array}\]

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 < -6.1157351543722565e+62

    1. Initial program 44.3

      \[\log \left(\sqrt{re \cdot re + im \cdot im}\right)\]
    2. Initial simplification44.3

      \[\leadsto \log \left(\sqrt{re \cdot re + im \cdot im}\right)\]
    3. Taylor expanded around -inf 10.0

      \[\leadsto \log \color{blue}{\left(-1 \cdot re\right)}\]
    4. Simplified10.0

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

    if -6.1157351543722565e+62 < re < 2.194524025777904e+126

    1. Initial program 21.5

      \[\log \left(\sqrt{re \cdot re + im \cdot im}\right)\]
    2. Initial simplification21.5

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

    if 2.194524025777904e+126 < re

    1. Initial program 55.6

      \[\log \left(\sqrt{re \cdot re + im \cdot im}\right)\]
    2. Initial simplification55.6

      \[\leadsto \log \left(\sqrt{re \cdot re + im \cdot im}\right)\]
    3. Taylor expanded around inf 8.1

      \[\leadsto \log \color{blue}{re}\]
  3. Recombined 3 regimes into one program.
  4. Final simplification17.3

    \[\leadsto \begin{array}{l} \mathbf{if}\;re \le -6.1157351543722565 \cdot 10^{+62}:\\ \;\;\;\;\log \left(-re\right)\\ \mathbf{elif}\;re \le 2.194524025777904 \cdot 10^{+126}:\\ \;\;\;\;\log \left(\sqrt{im \cdot im + re \cdot re}\right)\\ \mathbf{else}:\\ \;\;\;\;\log re\\ \end{array}\]

Runtime

Time bar (total: 3.6s)Debug logProfile

BaselineHerbieOracleSpan%
Regimes31.117.37.623.459%
herbie shell --seed 2018351 
(FPCore (re im)
  :name "math.log/1 on complex, real part"
  (log (sqrt (+ (* re re) (* im im)))))