\[\frac{a \cdot c + b \cdot d}{{c}^2 + {d}^2}\]
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: 8.4 s
Input Error: 12.7
Output Error: 4.3
Log:
Profile: 🕒
\(\begin{cases} (\left(\frac{a}{\left|c\right|}\right) * \left(\frac{c}{\left|c\right|}\right) + \left(\frac{d}{\left|c\right|} \cdot \frac{b}{\left|c\right|}\right))_* & \text{when } c \le -3.3148205f+22 \\ \frac{a \cdot c + b \cdot d}{{\left(\left|c\right|\right)}^2 + {\left(\left|d\right|\right)}^2} & \text{when } c \le 2.8363323f+14 \\ (\left(\frac{a}{\left|c\right|}\right) * \left(\frac{c}{\left|c\right|}\right) + \left(\frac{d}{\left|c\right|} \cdot \frac{b}{\left|c\right|}\right))_* & \text{otherwise} \end{cases}\)

    if c < -3.3148205f+22 or 2.8363323f+14 < c

    1. Started with
      \[\frac{a \cdot c + b \cdot d}{{c}^2 + {d}^2}\]
      21.0
    2. Using strategy rm
      21.0
    3. Applied add-sqr-sqrt to get
      \[\frac{a \cdot c + b \cdot d}{\color{red}{{c}^2} + {d}^2} \leadsto \frac{a \cdot c + b \cdot d}{\color{blue}{{\left(\sqrt{{c}^2}\right)}^2} + {d}^2}\]
      21.0
    4. Applied simplify to get
      \[\frac{a \cdot c + b \cdot d}{{\color{red}{\left(\sqrt{{c}^2}\right)}}^2 + {d}^2} \leadsto \frac{a \cdot c + b \cdot d}{{\color{blue}{\left(\left|c\right|\right)}}^2 + {d}^2}\]
      15.6
    5. Using strategy rm
      15.6
    6. Applied add-cube-cbrt to get
      \[\color{red}{\frac{a \cdot c + b \cdot d}{{\left(\left|c\right|\right)}^2 + {d}^2}} \leadsto \color{blue}{{\left(\sqrt[3]{\frac{a \cdot c + b \cdot d}{{\left(\left|c\right|\right)}^2 + {d}^2}}\right)}^3}\]
      15.7
    7. Applied taylor to get
      \[{\left(\sqrt[3]{\frac{a \cdot c + b \cdot d}{{\left(\left|c\right|\right)}^2 + {d}^2}}\right)}^3 \leadsto {\left(\sqrt[3]{\frac{b \cdot d}{{\left(\left|c\right|\right)}^2} + \frac{c \cdot a}{{\left(\left|c\right|\right)}^2}}\right)}^3\]
      13.5
    8. Taylor expanded around 0 to get
      \[{\left(\sqrt[3]{\color{red}{\frac{b \cdot d}{{\left(\left|c\right|\right)}^2} + \frac{c \cdot a}{{\left(\left|c\right|\right)}^2}}}\right)}^3 \leadsto {\left(\sqrt[3]{\color{blue}{\frac{b \cdot d}{{\left(\left|c\right|\right)}^2} + \frac{c \cdot a}{{\left(\left|c\right|\right)}^2}}}\right)}^3\]
      13.5
    9. Applied simplify to get
      \[{\left(\sqrt[3]{\frac{b \cdot d}{{\left(\left|c\right|\right)}^2} + \frac{c \cdot a}{{\left(\left|c\right|\right)}^2}}\right)}^3 \leadsto (\left(\frac{a}{\left|c\right|}\right) * \left(\frac{c}{\left|c\right|}\right) + \left(\frac{d}{\left|c\right|} \cdot \frac{b}{\left|c\right|}\right))_*\]
      0.0

    10. Applied final simplification

    if -3.3148205f+22 < c < 2.8363323f+14

    1. Started with
      \[\frac{a \cdot c + b \cdot d}{{c}^2 + {d}^2}\]
      9.5
    2. Using strategy rm
      9.5
    3. Applied add-sqr-sqrt to get
      \[\frac{a \cdot c + b \cdot d}{\color{red}{{c}^2} + {d}^2} \leadsto \frac{a \cdot c + b \cdot d}{\color{blue}{{\left(\sqrt{{c}^2}\right)}^2} + {d}^2}\]
      9.4
    4. Applied simplify to get
      \[\frac{a \cdot c + b \cdot d}{{\color{red}{\left(\sqrt{{c}^2}\right)}}^2 + {d}^2} \leadsto \frac{a \cdot c + b \cdot d}{{\color{blue}{\left(\left|c\right|\right)}}^2 + {d}^2}\]
      8.8
    5. Using strategy rm
      8.8
    6. Applied add-sqr-sqrt to get
      \[\frac{a \cdot c + b \cdot d}{{\left(\left|c\right|\right)}^2 + \color{red}{{d}^2}} \leadsto \frac{a \cdot c + b \cdot d}{{\left(\left|c\right|\right)}^2 + \color{blue}{{\left(\sqrt{{d}^2}\right)}^2}}\]
      8.8
    7. Applied simplify to get
      \[\frac{a \cdot c + b \cdot d}{{\left(\left|c\right|\right)}^2 + {\color{red}{\left(\sqrt{{d}^2}\right)}}^2} \leadsto \frac{a \cdot c + b \cdot d}{{\left(\left|c\right|\right)}^2 + {\color{blue}{\left(\left|d\right|\right)}}^2}\]
      6.0

  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))))))