\[\frac{\left(-b\right) + \sqrt{{b}^2 - \left(4 \cdot a\right) \cdot c}}{2 \cdot a}\]
Test:
The quadratic formula (r1)
Bits:
128 bits
Bits error versus a
Bits error versus b
Bits error versus c
Time: 14.3 s
Input Error: 16.2
Output Error: 3.8
Log:
Profile: 🕒
\(\begin{cases} \frac{c}{b} - \frac{b}{a} & \text{when } b \le -1.6844219f+10 \\ \frac{1}{2} \cdot \frac{(1 * \left(-b\right) + \left(\sqrt{{b}^2 - 4 \cdot \left(c \cdot a\right)}\right))_*}{a} & \text{when } b \le 3.426723f-06 \\ \frac{\frac{\left(4 \cdot a\right) \cdot c}{\left(-b\right) - \sqrt{{b}^2 - \left(4 \cdot a\right) \cdot c}}}{2 \cdot a} & \text{when } b \le 2.2299319f+17 \\ \frac{c}{b} \cdot \frac{-2}{2} & \text{otherwise} \end{cases}\)

    if b < -1.6844219f+10

    1. Started with
      \[\frac{\left(-b\right) + \sqrt{{b}^2 - \left(4 \cdot a\right) \cdot c}}{2 \cdot a}\]
      21.2
    2. Applied taylor to get
      \[\frac{\left(-b\right) + \sqrt{{b}^2 - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \leadsto \frac{2 \cdot \frac{c \cdot a}{b} - 2 \cdot b}{2 \cdot a}\]
      6.1
    3. Taylor expanded around -inf to get
      \[\frac{\color{red}{2 \cdot \frac{c \cdot a}{b} - 2 \cdot b}}{2 \cdot a} \leadsto \frac{\color{blue}{2 \cdot \frac{c \cdot a}{b} - 2 \cdot b}}{2 \cdot a}\]
      6.1
    4. Applied simplify to get
      \[\color{red}{\frac{2 \cdot \frac{c \cdot a}{b} - 2 \cdot b}{2 \cdot a}} \leadsto \color{blue}{\frac{\frac{c}{b}}{1} - \frac{b}{a}}\]
      0.0
    5. Applied simplify to get
      \[\color{red}{\frac{\frac{c}{b}}{1}} - \frac{b}{a} \leadsto \color{blue}{\frac{c}{b}} - \frac{b}{a}\]
      0.0

    if -1.6844219f+10 < b < 3.426723f-06

    1. Started with
      \[\frac{\left(-b\right) + \sqrt{{b}^2 - \left(4 \cdot a\right) \cdot c}}{2 \cdot a}\]
      6.5
    2. Using strategy rm
      6.5
    3. Applied *-un-lft-identity to get
      \[\frac{\color{red}{\left(-b\right)} + \sqrt{{b}^2 - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \leadsto \frac{\color{blue}{1 \cdot \left(-b\right)} + \sqrt{{b}^2 - \left(4 \cdot a\right) \cdot c}}{2 \cdot a}\]
      6.5
    4. Applied fma-def to get
      \[\frac{\color{red}{1 \cdot \left(-b\right) + \sqrt{{b}^2 - \left(4 \cdot a\right) \cdot c}}}{2 \cdot a} \leadsto \frac{\color{blue}{(1 * \left(-b\right) + \left(\sqrt{{b}^2 - \left(4 \cdot a\right) \cdot c}\right))_*}}{2 \cdot a}\]
      6.5
    5. Applied taylor to get
      \[\frac{(1 * \left(-b\right) + \left(\sqrt{{b}^2 - \left(4 \cdot a\right) \cdot c}\right))_*}{2 \cdot a} \leadsto \frac{1}{2} \cdot \frac{(1 * \left(-b\right) + \left(\sqrt{{b}^2 - 4 \cdot \left(c \cdot a\right)}\right))_*}{a}\]
      6.5
    6. Taylor expanded around 0 to get
      \[\color{red}{\frac{1}{2} \cdot \frac{(1 * \left(-b\right) + \left(\sqrt{{b}^2 - 4 \cdot \left(c \cdot a\right)}\right))_*}{a}} \leadsto \color{blue}{\frac{1}{2} \cdot \frac{(1 * \left(-b\right) + \left(\sqrt{{b}^2 - 4 \cdot \left(c \cdot a\right)}\right))_*}{a}}\]
      6.5

    if 3.426723f-06 < b < 2.2299319f+17

    1. Started with
      \[\frac{\left(-b\right) + \sqrt{{b}^2 - \left(4 \cdot a\right) \cdot c}}{2 \cdot a}\]
      20.6
    2. Using strategy rm
      20.6
    3. Applied flip-+ to get
      \[\frac{\color{red}{\left(-b\right) + \sqrt{{b}^2 - \left(4 \cdot a\right) \cdot c}}}{2 \cdot a} \leadsto \frac{\color{blue}{\frac{{\left(-b\right)}^2 - {\left(\sqrt{{b}^2 - \left(4 \cdot a\right) \cdot c}\right)}^2}{\left(-b\right) - \sqrt{{b}^2 - \left(4 \cdot a\right) \cdot c}}}}{2 \cdot a}\]
      23.4
    4. Applied simplify to get
      \[\frac{\frac{\color{red}{{\left(-b\right)}^2 - {\left(\sqrt{{b}^2 - \left(4 \cdot a\right) \cdot c}\right)}^2}}{\left(-b\right) - \sqrt{{b}^2 - \left(4 \cdot a\right) \cdot c}}}{2 \cdot a} \leadsto \frac{\frac{\color{blue}{\left(4 \cdot a\right) \cdot c}}{\left(-b\right) - \sqrt{{b}^2 - \left(4 \cdot a\right) \cdot c}}}{2 \cdot a}\]
      4.9

    if 2.2299319f+17 < b

    1. Started with
      \[\frac{\left(-b\right) + \sqrt{{b}^2 - \left(4 \cdot a\right) \cdot c}}{2 \cdot a}\]
      30.2
    2. Applied taylor to get
      \[\frac{\left(-b\right) + \sqrt{{b}^2 - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \leadsto \frac{-2 \cdot \frac{c \cdot a}{b}}{2 \cdot a}\]
      7.3
    3. Taylor expanded around inf to get
      \[\frac{\color{red}{-2 \cdot \frac{c \cdot a}{b}}}{2 \cdot a} \leadsto \frac{\color{blue}{-2 \cdot \frac{c \cdot a}{b}}}{2 \cdot a}\]
      7.3
    4. Applied simplify to get
      \[\color{red}{\frac{-2 \cdot \frac{c \cdot a}{b}}{2 \cdot a}} \leadsto \color{blue}{\frac{c}{b} \cdot \frac{-2}{2}}\]
      0

  1. Removed slow pow expressions

Original test:


(lambda ((a default) (b default) (c default))
  #:name "The quadratic formula (r1)"
  (/ (+ (- b) (sqrt (- (sqr b) (* (* 4 a) c)))) (* 2 a))
  #:target
  (if (< b 0) (/ (+ (- b) (sqrt (- (sqr b) (* (* 4 a) c)))) (* 2 a)) (/ c (* a (/ (- (- b) (sqrt (- (sqr b) (* (* 4 a) c)))) (* 2 a))))))