\[\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}\]
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: 12.2 s
Input Error: 14.0
Output Error: 3.5
Log:
Profile: 🕒
\(\begin{cases} \frac{b}{c} - \frac{d}{c} \cdot \frac{a}{c} & \text{when } c \le -3.5319744f+18 \\ \frac{b \cdot c}{{c}^2 + {d}^2} - \frac{a \cdot d}{{c}^2 + {d}^2} & \text{when } c \le -1.04332377f-22 \\ -\frac{a}{d} & \text{when } c \le 8.068465f-19 \\ \frac{b \cdot c}{{c}^2 + {d}^2} - \frac{a \cdot d}{{c}^2 + {d}^2} & \text{when } c \le 2.448105f+07 \\ \frac{b}{c} - \frac{d}{c} \cdot \frac{a}{c} & \text{otherwise} \end{cases}\)

    if c < -3.5319744f+18 or 2.448105f+07 < c

    1. Started with
      \[\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}\]
      20.1
    2. Using strategy rm
      20.1
    3. Applied add-sqr-sqrt to get
      \[\frac{b \cdot c - a \cdot d}{\color{red}{{c}^2 + {d}^2}} \leadsto \frac{b \cdot c - a \cdot d}{\color{blue}{{\left(\sqrt{{c}^2 + {d}^2}\right)}^2}}\]
      20.1
    4. Applied taylor to get
      \[\frac{b \cdot c - a \cdot d}{{\left(\sqrt{{c}^2 + {d}^2}\right)}^2} \leadsto \frac{b \cdot c - a \cdot d}{{\left(-1 \cdot c\right)}^2}\]
      18.9
    5. Taylor expanded around -inf to get
      \[\frac{b \cdot c - a \cdot d}{{\color{red}{\left(-1 \cdot c\right)}}^2} \leadsto \frac{b \cdot c - a \cdot d}{{\color{blue}{\left(-1 \cdot c\right)}}^2}\]
      18.9
    6. Applied simplify to get
      \[\color{red}{\frac{b \cdot c - a \cdot d}{{\left(-1 \cdot c\right)}^2}} \leadsto \color{blue}{\frac{b}{c} - \frac{d}{c} \cdot \frac{a}{c}}\]
      0.3

    if -3.5319744f+18 < c < -1.04332377f-22 or 8.068465f-19 < c < 2.448105f+07

    1. Started with
      \[\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}\]
      7.9
    2. Using strategy rm
      7.9
    3. Applied div-sub to get
      \[\color{red}{\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}} \leadsto \color{blue}{\frac{b \cdot c}{{c}^2 + {d}^2} - \frac{a \cdot d}{{c}^2 + {d}^2}}\]
      7.9

    if -1.04332377f-22 < c < 8.068465f-19

    1. Started with
      \[\frac{b \cdot c - a \cdot d}{{c}^2 + {d}^2}\]
      16.1
    2. Using strategy rm
      16.1
    3. Applied add-exp-log to get
      \[\frac{b \cdot c - a \cdot d}{\color{red}{{c}^2 + {d}^2}} \leadsto \frac{b \cdot c - a \cdot d}{\color{blue}{e^{\log \left({c}^2 + {d}^2\right)}}}\]
      17.0
    4. Applied add-exp-log to get
      \[\frac{\color{red}{b \cdot c - a \cdot d}}{e^{\log \left({c}^2 + {d}^2\right)}} \leadsto \frac{\color{blue}{e^{\log \left(b \cdot c - a \cdot d\right)}}}{e^{\log \left({c}^2 + {d}^2\right)}}\]
      24.2
    5. Applied div-exp to get
      \[\color{red}{\frac{e^{\log \left(b \cdot c - a \cdot d\right)}}{e^{\log \left({c}^2 + {d}^2\right)}}} \leadsto \color{blue}{e^{\log \left(b \cdot c - a \cdot d\right) - \log \left({c}^2 + {d}^2\right)}}\]
      24.2
    6. Applied taylor to get
      \[e^{\log \left(b \cdot c - a \cdot d\right) - \log \left({c}^2 + {d}^2\right)} \leadsto e^{\left(\log a + \log -1\right) - \log d}\]
      30.6
    7. Taylor expanded around 0 to get
      \[\color{red}{e^{\left(\log a + \log -1\right) - \log d}} \leadsto \color{blue}{e^{\left(\log a + \log -1\right) - \log d}}\]
      30.6
    8. Applied simplify to get
      \[e^{\left(\log a + \log -1\right) - \log d} \leadsto \frac{-1}{d} \cdot a\]
      0.2

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

  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))))))