\[\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}\]
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: 19.9 s
Input Error: 13.0
Output Error: 4.3
Log:
Profile: 🕒
\(\begin{cases} -\frac{a}{d} & \text{when } d \le -1.0358282f+21 \\ \frac{b}{1} \cdot \frac{c}{{c}^2 + {d}^2} - \frac{a \cdot d}{{c}^2 + {d}^2} & \text{when } d \le -3.9317606f-27 \\ \frac{b}{c} - \frac{d}{c} \cdot \frac{a}{c} & \text{when } d \le 0.0038476672f0 \\ \frac{b \cdot c}{{c}^2 + {d}^2} - \frac{a}{1} \cdot \frac{d}{{c}^2 + {d}^2} & \text{when } d \le 1.3808528f+21 \\ -\frac{a}{d} & \text{otherwise} \end{cases}\)

    if d < -1.0358282f+21 or 1.3808528f+21 < d

    1. Started with
      \[\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}\]
      20.9
    2. Using strategy rm
      20.9
    3. Applied add-exp-log to get
      \[\color{red}{\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}} \leadsto \color{blue}{e^{\log \left(\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}\right)}}\]
      20.9
    4. Applied taylor to get
      \[e^{\log \left(\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}\right)} \leadsto e^{\left(\log a + \log -1\right) - \log d}\]
      30.9
    5. Taylor expanded around 0 to get
      \[e^{\color{red}{\left(\log a + \log -1\right) - \log d}} \leadsto e^{\color{blue}{\left(\log a + \log -1\right) - \log d}}\]
      30.9
    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 -1.0358282f+21 < d < -3.9317606f-27

    1. Started with
      \[\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}\]
      9.0
    2. Using strategy rm
      9.0
    3. Applied div-sub to get
      \[\color{red}{\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}} \leadsto \color{blue}{\frac{b \cdot c}{{c}^2 + {d}^2} - \frac{a \cdot d}{{c}^2 + {d}^2}}\]
      9.0
    4. Using strategy rm
      9.0
    5. Applied *-un-lft-identity to get
      \[\frac{b \cdot c}{\color{red}{{c}^2 + {d}^2}} - \frac{a \cdot d}{{c}^2 + {d}^2} \leadsto \frac{b \cdot c}{\color{blue}{1 \cdot \left({c}^2 + {d}^2\right)}} - \frac{a \cdot d}{{c}^2 + {d}^2}\]
      9.0
    6. Applied times-frac to get
      \[\color{red}{\frac{b \cdot c}{1 \cdot \left({c}^2 + {d}^2\right)}} - \frac{a \cdot d}{{c}^2 + {d}^2} \leadsto \color{blue}{\frac{b}{1} \cdot \frac{c}{{c}^2 + {d}^2}} - \frac{a \cdot d}{{c}^2 + {d}^2}\]
      8.3

    if -3.9317606f-27 < d < 0.0038476672f0

    1. Started with
      \[\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}\]
      12.0
    2. Using strategy rm
      12.0
    3. Applied add-sqr-sqrt to get
      \[\frac{b \cdot c - a \cdot d}{\color{red}{{c}^2 + {d}^2}} \leadsto \frac{b \cdot c - a \cdot d}{\color{blue}{{\left(\sqrt{{c}^2 + {d}^2}\right)}^2}}\]
      11.9
    4. Applied taylor to get
      \[\frac{b \cdot c - a \cdot d}{{\left(\sqrt{{c}^2 + {d}^2}\right)}^2} \leadsto \frac{b \cdot c - a \cdot d}{{\left(-1 \cdot c\right)}^2}\]
      10.8
    5. Taylor expanded around -inf to get
      \[\frac{b \cdot c - a \cdot d}{{\color{red}{\left(-1 \cdot c\right)}}^2} \leadsto \frac{b \cdot c - a \cdot d}{{\color{blue}{\left(-1 \cdot c\right)}}^2}\]
      10.8
    6. Applied simplify to get
      \[\color{red}{\frac{b \cdot c - a \cdot d}{{\left(-1 \cdot c\right)}^2}} \leadsto \color{blue}{\frac{b}{c} - \frac{d}{c} \cdot \frac{a}{c}}\]
      1.0

    if 0.0038476672f0 < d < 1.3808528f+21

    1. Started with
      \[\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}\]
      10.6
    2. Using strategy rm
      10.6
    3. Applied div-sub to get
      \[\color{red}{\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}} \leadsto \color{blue}{\frac{b \cdot c}{{c}^2 + {d}^2} - \frac{a \cdot d}{{c}^2 + {d}^2}}\]
      10.6
    4. Using strategy rm
      10.6
    5. Applied *-un-lft-identity to get
      \[\frac{b \cdot c}{{c}^2 + {d}^2} - \frac{a \cdot d}{\color{red}{{c}^2 + {d}^2}} \leadsto \frac{b \cdot c}{{c}^2 + {d}^2} - \frac{a \cdot d}{\color{blue}{1 \cdot \left({c}^2 + {d}^2\right)}}\]
      10.6
    6. Applied times-frac to get
      \[\frac{b \cdot c}{{c}^2 + {d}^2} - \color{red}{\frac{a \cdot d}{1 \cdot \left({c}^2 + {d}^2\right)}} \leadsto \frac{b \cdot c}{{c}^2 + {d}^2} - \color{blue}{\frac{a}{1} \cdot \frac{d}{{c}^2 + {d}^2}}\]
      8.5

  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))))))