Average Error: 32.8 → 10.3
Time: 18.3s
Precision: 64
\[\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a}\]
\[\begin{array}{l} \mathbf{if}\;b \le -1.6239127264630285 \cdot 10^{-63}:\\ \;\;\;\;-\frac{c}{b}\\ \mathbf{elif}\;b \le 7.052614559736995 \cdot 10^{+62}:\\ \;\;\;\;\frac{\frac{-1}{2}}{a} \cdot \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c} + \frac{\frac{-1}{2}}{a} \cdot b\\ \mathbf{else}:\\ \;\;\;\;\frac{c}{b} - \frac{b}{a}\\ \end{array}\]
\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a}
\begin{array}{l}
\mathbf{if}\;b \le -1.6239127264630285 \cdot 10^{-63}:\\
\;\;\;\;-\frac{c}{b}\\

\mathbf{elif}\;b \le 7.052614559736995 \cdot 10^{+62}:\\
\;\;\;\;\frac{\frac{-1}{2}}{a} \cdot \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c} + \frac{\frac{-1}{2}}{a} \cdot b\\

\mathbf{else}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\

\end{array}
double f(double a, double b, double c) {
        double r3679201 = b;
        double r3679202 = -r3679201;
        double r3679203 = r3679201 * r3679201;
        double r3679204 = 4.0;
        double r3679205 = a;
        double r3679206 = c;
        double r3679207 = r3679205 * r3679206;
        double r3679208 = r3679204 * r3679207;
        double r3679209 = r3679203 - r3679208;
        double r3679210 = sqrt(r3679209);
        double r3679211 = r3679202 - r3679210;
        double r3679212 = 2.0;
        double r3679213 = r3679212 * r3679205;
        double r3679214 = r3679211 / r3679213;
        return r3679214;
}

double f(double a, double b, double c) {
        double r3679215 = b;
        double r3679216 = -1.6239127264630285e-63;
        bool r3679217 = r3679215 <= r3679216;
        double r3679218 = c;
        double r3679219 = r3679218 / r3679215;
        double r3679220 = -r3679219;
        double r3679221 = 7.052614559736995e+62;
        bool r3679222 = r3679215 <= r3679221;
        double r3679223 = -0.5;
        double r3679224 = a;
        double r3679225 = r3679223 / r3679224;
        double r3679226 = r3679215 * r3679215;
        double r3679227 = 4.0;
        double r3679228 = r3679227 * r3679224;
        double r3679229 = r3679228 * r3679218;
        double r3679230 = r3679226 - r3679229;
        double r3679231 = sqrt(r3679230);
        double r3679232 = r3679225 * r3679231;
        double r3679233 = r3679225 * r3679215;
        double r3679234 = r3679232 + r3679233;
        double r3679235 = r3679215 / r3679224;
        double r3679236 = r3679219 - r3679235;
        double r3679237 = r3679222 ? r3679234 : r3679236;
        double r3679238 = r3679217 ? r3679220 : r3679237;
        return r3679238;
}

Error

Bits error versus a

Bits error versus b

Bits error versus c

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Target

Original32.8
Target20.1
Herbie10.3
\[\begin{array}{l} \mathbf{if}\;b \lt 0:\\ \;\;\;\;\frac{c}{a \cdot \frac{\left(-b\right) + \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a}}\\ \mathbf{else}:\\ \;\;\;\;\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a}\\ \end{array}\]

Derivation

  1. Split input into 3 regimes
  2. if b < -1.6239127264630285e-63

    1. Initial program 52.2

      \[\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a}\]
    2. Taylor expanded around -inf 8.6

      \[\leadsto \color{blue}{-1 \cdot \frac{c}{b}}\]
    3. Simplified8.6

      \[\leadsto \color{blue}{-\frac{c}{b}}\]

    if -1.6239127264630285e-63 < b < 7.052614559736995e+62

    1. Initial program 13.9

      \[\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a}\]
    2. Using strategy rm
    3. Applied clear-num14.0

      \[\leadsto \color{blue}{\frac{1}{\frac{2 \cdot a}{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}}}\]
    4. Using strategy rm
    5. Applied div-inv14.1

      \[\leadsto \frac{1}{\color{blue}{\left(2 \cdot a\right) \cdot \frac{1}{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}}}\]
    6. Applied add-cube-cbrt14.1

      \[\leadsto \frac{\color{blue}{\left(\sqrt[3]{1} \cdot \sqrt[3]{1}\right) \cdot \sqrt[3]{1}}}{\left(2 \cdot a\right) \cdot \frac{1}{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}}\]
    7. Applied times-frac14.1

      \[\leadsto \color{blue}{\frac{\sqrt[3]{1} \cdot \sqrt[3]{1}}{2 \cdot a} \cdot \frac{\sqrt[3]{1}}{\frac{1}{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}}}\]
    8. Simplified14.1

      \[\leadsto \color{blue}{\frac{\frac{1}{2}}{a}} \cdot \frac{\sqrt[3]{1}}{\frac{1}{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}}\]
    9. Simplified14.0

      \[\leadsto \frac{\frac{1}{2}}{a} \cdot \color{blue}{\left(-\left(b + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}\right)\right)}\]
    10. Using strategy rm
    11. Applied distribute-neg-in14.0

      \[\leadsto \frac{\frac{1}{2}}{a} \cdot \color{blue}{\left(\left(-b\right) + \left(-\sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}\right)\right)}\]
    12. Applied distribute-rgt-in14.1

      \[\leadsto \color{blue}{\left(-b\right) \cdot \frac{\frac{1}{2}}{a} + \left(-\sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}\right) \cdot \frac{\frac{1}{2}}{a}}\]

    if 7.052614559736995e+62 < b

    1. Initial program 38.1

      \[\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a}\]
    2. Taylor expanded around inf 4.7

      \[\leadsto \color{blue}{\frac{c}{b} - \frac{b}{a}}\]
  3. Recombined 3 regimes into one program.
  4. Final simplification10.3

    \[\leadsto \begin{array}{l} \mathbf{if}\;b \le -1.6239127264630285 \cdot 10^{-63}:\\ \;\;\;\;-\frac{c}{b}\\ \mathbf{elif}\;b \le 7.052614559736995 \cdot 10^{+62}:\\ \;\;\;\;\frac{\frac{-1}{2}}{a} \cdot \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c} + \frac{\frac{-1}{2}}{a} \cdot b\\ \mathbf{else}:\\ \;\;\;\;\frac{c}{b} - \frac{b}{a}\\ \end{array}\]

Reproduce

herbie shell --seed 2019158 
(FPCore (a b c)
  :name "The quadratic formula (r2)"

  :herbie-target
  (if (< b 0) (/ c (* a (/ (+ (- b) (sqrt (- (* b b) (* 4 (* a c))))) (* 2 a)))) (/ (- (- b) (sqrt (- (* b b) (* 4 (* a c))))) (* 2 a)))

  (/ (- (- b) (sqrt (- (* b b) (* 4 (* a c))))) (* 2 a)))