Average Error: 32.1 → 12.7
Time: 22.9s
Precision: 64
Internal precision: 128
\[\frac{\log \left(\sqrt{re \cdot re + im \cdot im}\right)}{\log 10}\]
\[\begin{array}{l} \mathbf{if}\;im \le -3.1392156119995164 \cdot 10^{+40}:\\ \;\;\;\;\frac{\log \left(-im\right)}{\log 10}\\ \mathbf{if}\;im \le 5.8170505962259145 \cdot 10^{+31}:\\ \;\;\;\;\frac{3}{\log 10 \cdot \frac{1}{\log \left(\sqrt[3]{\sqrt{{im}^2 + re \cdot re}}\right)}}\\ \mathbf{else}:\\ \;\;\;\;\frac{\log im}{\log 10}\\ \end{array}\]

Error

Bits error versus re

Bits error versus im

Derivation

  1. Split input into 3 regimes.
  2. if im < -3.1392156119995164e+40

    1. Initial program 45.8

      \[\frac{\log \left(\sqrt{re \cdot re + im \cdot im}\right)}{\log 10}\]
    2. Applied simplify 45.8

      \[\leadsto \color{blue}{\frac{\log \left(\sqrt{{im}^2 + re \cdot re}\right)}{\log 10}}\]
    3. Applied taylor 0.6

      \[\leadsto \frac{\log \left(-1 \cdot im\right)}{\log 10}\]
    4. Taylor expanded around -inf 0.6

      \[\leadsto \frac{\log \color{blue}{\left(-1 \cdot im\right)}}{\log 10}\]
    5. Applied simplify 0.6

      \[\leadsto \color{blue}{\frac{\log \left(-im\right)}{\log 10}}\]

    if -3.1392156119995164e+40 < im < 5.8170505962259145e+31

    1. Initial program 22.3

      \[\frac{\log \left(\sqrt{re \cdot re + im \cdot im}\right)}{\log 10}\]
    2. Applied simplify 22.3

      \[\leadsto \color{blue}{\frac{\log \left(\sqrt{{im}^2 + re \cdot re}\right)}{\log 10}}\]
    3. Using strategy rm
    4. Applied add-cube-cbrt 22.3

      \[\leadsto \frac{\log \color{blue}{\left({\left(\sqrt[3]{\sqrt{{im}^2 + re \cdot re}}\right)}^3\right)}}{\log 10}\]
    5. Using strategy rm
    6. Applied pow3 22.3

      \[\leadsto \frac{\log \color{blue}{\left({\left(\sqrt[3]{\sqrt{{im}^2 + re \cdot re}}\right)}^{3}\right)}}{\log 10}\]
    7. Applied log-pow 22.3

      \[\leadsto \frac{\color{blue}{3 \cdot \log \left(\sqrt[3]{\sqrt{{im}^2 + re \cdot re}}\right)}}{\log 10}\]
    8. Applied associate-/l* 22.3

      \[\leadsto \color{blue}{\frac{3}{\frac{\log 10}{\log \left(\sqrt[3]{\sqrt{{im}^2 + re \cdot re}}\right)}}}\]
    9. Using strategy rm
    10. Applied div-inv 22.3

      \[\leadsto \frac{3}{\color{blue}{\log 10 \cdot \frac{1}{\log \left(\sqrt[3]{\sqrt{{im}^2 + re \cdot re}}\right)}}}\]

    if 5.8170505962259145e+31 < im

    1. Initial program 42.7

      \[\frac{\log \left(\sqrt{re \cdot re + im \cdot im}\right)}{\log 10}\]
    2. Applied simplify 42.7

      \[\leadsto \color{blue}{\frac{\log \left(\sqrt{{im}^2 + re \cdot re}\right)}{\log 10}}\]
    3. Applied taylor 0.6

      \[\leadsto \frac{\log im}{\log 10}\]
    4. Taylor expanded around inf 0.6

      \[\leadsto \frac{\log \color{blue}{im}}{\log 10}\]
  3. Recombined 3 regimes into one program.
  4. Removed slow pow expressions

Runtime

Time bar (total: 22.9s) Debug log

Please include this information when filing a bug report:

herbie --seed '#(283823130 3901138988 2672121530 4088188533 769191305 236709709)'
(FPCore (re im)
  :name "math.log10 on complex, real part"
  (/ (log (sqrt (+ (* re re) (* im im)))) (log 10)))