\[\frac{a \cdot c + b \cdot d}{{c}^2 + {d}^2}\]
Test:
Complex division, real part
Bits:
128 bits
Bits error versus a
Bits error versus b
Bits error versus c
Bits error versus d
Time: 12.7 s
Input Error: 14.3
Output Error: 2.7
Log:
Profile: 🕒
\(\begin{cases} \frac{c}{d} \cdot \frac{a}{d} + \frac{b}{d} & \text{when } d \le -1461388.5f0 \\ \frac{a}{c} + \frac{b}{c} \cdot \frac{d}{c} & \text{when } d \le 3.1068393f-18 \\ \frac{a \cdot c + b \cdot d}{{\left(\sqrt{{c}^2 + {d}^2}\right)}^2} & \text{when } d \le 4.759657f+20 \\ \frac{c}{d} \cdot \frac{a}{d} + \frac{b}{d} & \text{otherwise} \end{cases}\)

    if d < -1461388.5f0 or 4.759657f+20 < d

    1. Started with
      \[\frac{a \cdot c + b \cdot d}{{c}^2 + {d}^2}\]
      19.6
    2. Using strategy rm
      19.6
    3. Applied add-sqr-sqrt to get
      \[\frac{a \cdot c + b \cdot d}{\color{red}{{c}^2 + {d}^2}} \leadsto \frac{a \cdot c + b \cdot d}{\color{blue}{{\left(\sqrt{{c}^2 + {d}^2}\right)}^2}}\]
      19.6
    4. Applied taylor to get
      \[\frac{a \cdot c + b \cdot d}{{\left(\sqrt{{c}^2 + {d}^2}\right)}^2} \leadsto \frac{a \cdot c + b \cdot d}{{d}^2}\]
      18.2
    5. Taylor expanded around 0 to get
      \[\frac{a \cdot c + b \cdot d}{{\color{red}{d}}^2} \leadsto \frac{a \cdot c + b \cdot d}{{\color{blue}{d}}^2}\]
      18.2
    6. Applied taylor to get
      \[\frac{a \cdot c + b \cdot d}{{d}^2} \leadsto \frac{c \cdot a}{{d}^2} + \frac{b}{d}\]
      5.7
    7. Taylor expanded around 0 to get
      \[\color{red}{\frac{c \cdot a}{{d}^2} + \frac{b}{d}} \leadsto \color{blue}{\frac{c \cdot a}{{d}^2} + \frac{b}{d}}\]
      5.7
    8. Applied simplify to get
      \[\frac{c \cdot a}{{d}^2} + \frac{b}{d} \leadsto \frac{c}{d} \cdot \frac{a}{d} + \frac{b}{d}\]
      0.3

    9. Applied final simplification

    if -1461388.5f0 < d < 3.1068393f-18

    1. Started with
      \[\frac{a \cdot c + b \cdot d}{{c}^2 + {d}^2}\]
      12.6
    2. Using strategy rm
      12.6
    3. Applied add-sqr-sqrt to get
      \[\frac{a \cdot c + b \cdot d}{\color{red}{{c}^2 + {d}^2}} \leadsto \frac{a \cdot c + b \cdot d}{\color{blue}{{\left(\sqrt{{c}^2 + {d}^2}\right)}^2}}\]
      12.6
    4. Using strategy rm
      12.6
    5. Applied add-exp-log to get
      \[\frac{a \cdot c + b \cdot d}{{\color{red}{\left(\sqrt{{c}^2 + {d}^2}\right)}}^2} \leadsto \frac{a \cdot c + b \cdot d}{{\color{blue}{\left(e^{\log \left(\sqrt{{c}^2 + {d}^2}\right)}\right)}}^2}\]
      13.7
    6. Applied taylor to get
      \[\frac{a \cdot c + b \cdot d}{{\left(e^{\log \left(\sqrt{{c}^2 + {d}^2}\right)}\right)}^2} \leadsto \frac{a}{c} + \frac{b \cdot d}{{c}^2}\]
      3.0
    7. Taylor expanded around inf to get
      \[\color{red}{\frac{a}{c} + \frac{b \cdot d}{{c}^2}} \leadsto \color{blue}{\frac{a}{c} + \frac{b \cdot d}{{c}^2}}\]
      3.0
    8. Applied simplify to get
      \[\frac{a}{c} + \frac{b \cdot d}{{c}^2} \leadsto \frac{a}{c} + \frac{b}{c} \cdot \frac{d}{c}\]
      0.8

    9. Applied final simplification

    if 3.1068393f-18 < d < 4.759657f+20

    1. Started with
      \[\frac{a \cdot c + b \cdot d}{{c}^2 + {d}^2}\]
      8.9
    2. Using strategy rm
      8.9
    3. Applied add-sqr-sqrt to get
      \[\frac{a \cdot c + b \cdot d}{\color{red}{{c}^2 + {d}^2}} \leadsto \frac{a \cdot c + b \cdot d}{\color{blue}{{\left(\sqrt{{c}^2 + {d}^2}\right)}^2}}\]
      8.9

  1. Removed slow pow expressions

Original test:


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