\[\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}\]
Test:
Complex division, imag part
Bits:
128 bits
Bits error versus a
Bits error versus b
Bits error versus c
Bits error versus d
Time: 12.9 s
Input Error: 25.7
Output Error: 9.0
Log:
Profile: 🕒
\(\begin{cases} -\frac{a}{d} & \text{when } d \le -3.3416373575121975 \cdot 10^{+67} \\ \frac{1}{\frac{{c}^2 + {d}^2}{b \cdot c - a \cdot d}} & \text{when } d \le -2.818412928592266 \cdot 10^{-174} \\ \frac{b}{c} - \frac{a \cdot d}{c \cdot c} & \text{when } d \le 6.657343370671305 \cdot 10^{-139} \\ \frac{1}{\frac{{c}^2 + {d}^2}{b \cdot c - a \cdot d}} & \text{when } d \le 1.2610866829211587 \cdot 10^{+151} \\ -\frac{a}{d} & \text{otherwise} \end{cases}\)

    if d < -3.3416373575121975e+67 or 1.2610866829211587e+151 < d

    1. Started with
      \[\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}\]
      40.3
    2. Using strategy rm
      40.3
    3. Applied add-exp-log to get
      \[\color{red}{\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}} \leadsto \color{blue}{e^{\log \left(\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}\right)}}\]
      43.1
    4. Applied taylor to get
      \[e^{\log \left(\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}\right)} \leadsto e^{\left(\log a + \log -1\right) - \log d}\]
      62.9
    5. Taylor expanded around 0 to get
      \[e^{\color{red}{\left(\log a + \log -1\right) - \log d}} \leadsto e^{\color{blue}{\left(\log a + \log -1\right) - \log d}}\]
      62.9
    6. Applied simplify to get
      \[e^{\left(\log a + \log -1\right) - \log d} \leadsto \frac{-1}{d} \cdot a\]
      0.2

    7. Applied final simplification
    8. Applied simplify to get
      \[\color{red}{\frac{-1}{d} \cdot a} \leadsto \color{blue}{-\frac{a}{d}}\]
      0

    if -3.3416373575121975e+67 < d < -2.818412928592266e-174

    1. Started with
      \[\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}\]
      15.5
    2. Using strategy rm
      15.5
    3. Applied clear-num to get
      \[\color{red}{\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}} \leadsto \color{blue}{\frac{1}{\frac{{c}^2 + {d}^2}{b \cdot c - a \cdot d}}}\]
      15.7

    if -2.818412928592266e-174 < d < 6.657343370671305e-139

    1. Started with
      \[\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}\]
      22.9
    2. Using strategy rm
      22.9
    3. Applied div-inv to get
      \[\color{red}{\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}} \leadsto \color{blue}{\left(b \cdot c - a \cdot d\right) \cdot \frac{1}{{c}^2 + {d}^2}}\]
      23.2
    4. Using strategy rm
      23.2
    5. Applied add-sqr-sqrt to get
      \[\left(b \cdot c - a \cdot d\right) \cdot \color{red}{\frac{1}{{c}^2 + {d}^2}} \leadsto \left(b \cdot c - a \cdot d\right) \cdot \color{blue}{{\left(\sqrt{\frac{1}{{c}^2 + {d}^2}}\right)}^2}\]
      23.3
    6. Using strategy rm
      23.3
    7. Applied add-cube-cbrt to get
      \[\left(b \cdot c - a \cdot d\right) \cdot {\color{red}{\left(\sqrt{\frac{1}{{c}^2 + {d}^2}}\right)}}^2 \leadsto \left(b \cdot c - a \cdot d\right) \cdot {\color{blue}{\left({\left(\sqrt[3]{\sqrt{\frac{1}{{c}^2 + {d}^2}}}\right)}^3\right)}}^2\]
      24.0
    8. Applied taylor to get
      \[\left(b \cdot c - a \cdot d\right) \cdot {\left({\left(\sqrt[3]{\sqrt{\frac{1}{{c}^2 + {d}^2}}}\right)}^3\right)}^2 \leadsto \frac{b}{c} - \frac{d \cdot a}{{c}^2}\]
      8.2
    9. Taylor expanded around inf to get
      \[\color{red}{\frac{b}{c} - \frac{d \cdot a}{{c}^2}} \leadsto \color{blue}{\frac{b}{c} - \frac{d \cdot a}{{c}^2}}\]
      8.2
    10. Applied simplify to get
      \[\frac{b}{c} - \frac{d \cdot a}{{c}^2} \leadsto \frac{b}{c} - \frac{a \cdot d}{c \cdot c}\]
      8.2

    11. Applied final simplification

    if 6.657343370671305e-139 < d < 1.2610866829211587e+151

    1. Started with
      \[\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}\]
      16.6
    2. Using strategy rm
      16.6
    3. Applied clear-num to get
      \[\color{red}{\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}} \leadsto \color{blue}{\frac{1}{\frac{{c}^2 + {d}^2}{b \cdot c - a \cdot d}}}\]
      16.8

  1. Removed slow pow expressions

Original test:


(lambda ((a default) (b default) (c default) (d default))
  #:name "Complex division, imag part"
  (/ (- (* b c) (* a d)) (+ (sqr c) (sqr d)))
  #:target
  (if (< (fabs d) (fabs c)) (/ (- b (* a (/ d c))) (+ c (* d (/ d c)))) (/ (+ (- a) (* b (/ c d))) (+ d (* c (/ c d))))))