Average Error: 30.5 → 17.0
Time: 5.6s
Precision: 64
Internal Precision: 576
\[\log \left(\sqrt{re \cdot re + im \cdot im}\right)\]
\[\begin{array}{l} \mathbf{if}\;re \le -9.534618369590614 \cdot 10^{+92}:\\ \;\;\;\;\log \left(-re\right)\\ \mathbf{elif}\;re \le 7.0324657533777544 \cdot 10^{-301}:\\ \;\;\;\;\log \left(\sqrt{im \cdot im + re \cdot re}\right)\\ \mathbf{elif}\;re \le 1.5776960121797607 \cdot 10^{-157}:\\ \;\;\;\;\log im\\ \mathbf{elif}\;re \le 1.0588804460692496 \cdot 10^{+101}:\\ \;\;\;\;\log \left(\sqrt{im \cdot im + re \cdot re}\right)\\ \mathbf{else}:\\ \;\;\;\;\log re\\ \end{array}\]

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 4 regimes
  2. if re < -9.534618369590614e+92

    1. Initial program 48.6

      \[\log \left(\sqrt{re \cdot re + im \cdot im}\right)\]
    2. Taylor expanded around -inf 8.8

      \[\leadsto \log \color{blue}{\left(-1 \cdot re\right)}\]
    3. Simplified8.8

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

    if -9.534618369590614e+92 < re < 7.0324657533777544e-301 or 1.5776960121797607e-157 < re < 1.0588804460692496e+101

    1. Initial program 18.3

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

    if 7.0324657533777544e-301 < re < 1.5776960121797607e-157

    1. Initial program 31.8

      \[\log \left(\sqrt{re \cdot re + im \cdot im}\right)\]
    2. Taylor expanded around 0 34.0

      \[\leadsto \log \color{blue}{im}\]

    if 1.0588804460692496e+101 < re

    1. Initial program 50.1

      \[\log \left(\sqrt{re \cdot re + im \cdot im}\right)\]
    2. Taylor expanded around inf 9.1

      \[\leadsto \log \color{blue}{re}\]
  3. Recombined 4 regimes into one program.
  4. Final simplification17.0

    \[\leadsto \begin{array}{l} \mathbf{if}\;re \le -9.534618369590614 \cdot 10^{+92}:\\ \;\;\;\;\log \left(-re\right)\\ \mathbf{elif}\;re \le 7.0324657533777544 \cdot 10^{-301}:\\ \;\;\;\;\log \left(\sqrt{im \cdot im + re \cdot re}\right)\\ \mathbf{elif}\;re \le 1.5776960121797607 \cdot 10^{-157}:\\ \;\;\;\;\log im\\ \mathbf{elif}\;re \le 1.0588804460692496 \cdot 10^{+101}:\\ \;\;\;\;\log \left(\sqrt{im \cdot im + re \cdot re}\right)\\ \mathbf{else}:\\ \;\;\;\;\log re\\ \end{array}\]

Runtime

Time bar (total: 5.6s)Debug logProfile

herbie shell --seed 2018251 
(FPCore (re im)
  :name "math.log/1 on complex, real part"
  (log (sqrt (+ (* re re) (* im im)))))