\[\frac{a \cdot c + b \cdot d}{{c}^2 + {d}^2}\]
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: 11.7 s
Input Error: 12.8
Output Error: 2.6
Log:
Profile: 🕒
\(\begin{cases} (\left(\frac{b}{c}\right) * \left(\frac{d}{c}\right) + \left(\frac{a}{c}\right))_* & \text{when } c \le -9.398266f+14 \\ \frac{(c * a + \left(b \cdot d\right))_*}{{\left(\sqrt{c^2 + d^2}^*\right)}^2} & \text{when } c \le -4.298775f-18 \\ (\left(\frac{b}{\left|d\right|}\right) * \left(\frac{d}{\left|d\right|}\right) + \left(\frac{a}{\left|d\right|} \cdot \frac{c}{\left|d\right|}\right))_* & \text{when } c \le 3.2195558f-26 \\ \frac{(c * a + \left(b \cdot d\right))_*}{{\left(\sqrt{c^2 + d^2}^*\right)}^2} & \text{when } c \le 6.416234f+14 \\ (\left(\frac{b}{c}\right) * \left(\frac{d}{c}\right) + \left(\frac{a}{c}\right))_* & \text{otherwise} \end{cases}\)

    if c < -9.398266f+14 or 6.416234f+14 < c

    1. Started with
      \[\frac{a \cdot c + b \cdot d}{{c}^2 + {d}^2}\]
      20.9
    2. Using strategy rm
      20.9
    3. Applied add-exp-log to get
      \[\frac{a \cdot c + b \cdot d}{{c}^2 + \color{red}{{d}^2}} \leadsto \frac{a \cdot c + b \cdot d}{{c}^2 + \color{blue}{e^{\log \left({d}^2\right)}}}\]
      20.9
    4. Applied taylor to get
      \[\frac{a \cdot c + b \cdot d}{{c}^2 + e^{\log \left({d}^2\right)}} \leadsto \frac{a}{c} + \frac{b \cdot d}{{c}^2}\]
      6.3
    5. Taylor expanded around inf to get
      \[\color{red}{\frac{a}{c} + \frac{b \cdot d}{{c}^2}} \leadsto \color{blue}{\frac{a}{c} + \frac{b \cdot d}{{c}^2}}\]
      6.3
    6. Applied simplify to get
      \[\frac{a}{c} + \frac{b \cdot d}{{c}^2} \leadsto (\left(\frac{b}{c}\right) * \left(\frac{d}{c}\right) + \left(\frac{a}{c}\right))_*\]
      0.3

    7. Applied final simplification

    if -9.398266f+14 < c < -4.298775f-18 or 3.2195558f-26 < c < 6.416234f+14

    1. Started with
      \[\frac{a \cdot c + b \cdot d}{{c}^2 + {d}^2}\]
      8.1
    2. Using strategy rm
      8.1
    3. Applied add-sqr-sqrt to get
      \[\frac{a \cdot c + b \cdot d}{\color{red}{{c}^2 + {d}^2}} \leadsto \frac{a \cdot c + b \cdot d}{\color{blue}{{\left(\sqrt{{c}^2 + {d}^2}\right)}^2}}\]
      8.1
    4. Applied add-sqr-sqrt to get
      \[\frac{\color{red}{a \cdot c + b \cdot d}}{{\left(\sqrt{{c}^2 + {d}^2}\right)}^2} \leadsto \frac{\color{blue}{{\left(\sqrt{a \cdot c + b \cdot d}\right)}^2}}{{\left(\sqrt{{c}^2 + {d}^2}\right)}^2}\]
      20.1
    5. Applied square-undiv to get
      \[\color{red}{\frac{{\left(\sqrt{a \cdot c + b \cdot d}\right)}^2}{{\left(\sqrt{{c}^2 + {d}^2}\right)}^2}} \leadsto \color{blue}{{\left(\frac{\sqrt{a \cdot c + b \cdot d}}{\sqrt{{c}^2 + {d}^2}}\right)}^2}\]
      20.1
    6. Applied simplify to get
      \[{\color{red}{\left(\frac{\sqrt{a \cdot c + b \cdot d}}{\sqrt{{c}^2 + {d}^2}}\right)}}^2 \leadsto {\color{blue}{\left(\frac{\sqrt{(c * a + \left(d \cdot b\right))_*}}{\sqrt{c^2 + d^2}^*}\right)}}^2\]
      18.9
    7. Applied taylor to get
      \[{\left(\frac{\sqrt{(c * a + \left(d \cdot b\right))_*}}{\sqrt{c^2 + d^2}^*}\right)}^2 \leadsto {\left(\frac{\sqrt{(c * a + \left(b \cdot d\right))_*}}{\sqrt{c^2 + d^2}^*}\right)}^2\]
      18.9
    8. Taylor expanded around 0 to get
      \[{\left(\frac{\color{red}{\sqrt{(c * a + \left(b \cdot d\right))_*}}}{\sqrt{c^2 + d^2}^*}\right)}^2 \leadsto {\left(\frac{\color{blue}{\sqrt{(c * a + \left(b \cdot d\right))_*}}}{\sqrt{c^2 + d^2}^*}\right)}^2\]
      18.9
    9. Applied simplify to get
      \[{\left(\frac{\sqrt{(c * a + \left(b \cdot d\right))_*}}{\sqrt{c^2 + d^2}^*}\right)}^2 \leadsto \frac{(c * a + \left(b \cdot d\right))_*}{\sqrt{c^2 + d^2}^* \cdot \sqrt{c^2 + d^2}^*}\]
      5.4

    10. Applied final simplification
    11. Applied simplify to get
      \[\color{red}{\frac{(c * a + \left(b \cdot d\right))_*}{\sqrt{c^2 + d^2}^* \cdot \sqrt{c^2 + d^2}^*}} \leadsto \color{blue}{\frac{(c * a + \left(b \cdot d\right))_*}{{\left(\sqrt{c^2 + d^2}^*\right)}^2}}\]
      5.4

    if -4.298775f-18 < c < 3.2195558f-26

    1. Started with
      \[\frac{a \cdot c + b \cdot d}{{c}^2 + {d}^2}\]
      10.3
    2. Using strategy rm
      10.3
    3. Applied add-sqr-sqrt to get
      \[\frac{a \cdot c + b \cdot d}{{c}^2 + \color{red}{{d}^2}} \leadsto \frac{a \cdot c + b \cdot d}{{c}^2 + \color{blue}{{\left(\sqrt{{d}^2}\right)}^2}}\]
      10.3
    4. Applied simplify to get
      \[\frac{a \cdot c + b \cdot d}{{c}^2 + {\color{red}{\left(\sqrt{{d}^2}\right)}}^2} \leadsto \frac{a \cdot c + b \cdot d}{{c}^2 + {\color{blue}{\left(\left|d\right|\right)}}^2}\]
      6.3
    5. Using strategy rm
      6.3
    6. Applied add-cube-cbrt to get
      \[\color{red}{\frac{a \cdot c + b \cdot d}{{c}^2 + {\left(\left|d\right|\right)}^2}} \leadsto \color{blue}{{\left(\sqrt[3]{\frac{a \cdot c + b \cdot d}{{c}^2 + {\left(\left|d\right|\right)}^2}}\right)}^3}\]
      6.6
    7. Applied taylor to get
      \[{\left(\sqrt[3]{\frac{a \cdot c + b \cdot d}{{c}^2 + {\left(\left|d\right|\right)}^2}}\right)}^3 \leadsto {\left(\sqrt[3]{\frac{c \cdot a}{{\left(\left|d\right|\right)}^2} + \frac{b \cdot d}{{\left(\left|d\right|\right)}^2}}\right)}^3\]
      6.2
    8. Taylor expanded around 0 to get
      \[{\left(\sqrt[3]{\color{red}{\frac{c \cdot a}{{\left(\left|d\right|\right)}^2} + \frac{b \cdot d}{{\left(\left|d\right|\right)}^2}}}\right)}^3 \leadsto {\left(\sqrt[3]{\color{blue}{\frac{c \cdot a}{{\left(\left|d\right|\right)}^2} + \frac{b \cdot d}{{\left(\left|d\right|\right)}^2}}}\right)}^3\]
      6.2
    9. Applied simplify to get
      \[{\left(\sqrt[3]{\frac{c \cdot a}{{\left(\left|d\right|\right)}^2} + \frac{b \cdot d}{{\left(\left|d\right|\right)}^2}}\right)}^3 \leadsto (\left(\frac{b}{\left|d\right|}\right) * \left(\frac{d}{\left|d\right|}\right) + \left(\frac{a}{\left|d\right|} \cdot \frac{c}{\left|d\right|}\right))_*\]
      0.0

    10. Applied final simplification

  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))))))