Average Error: 34.1 → 12.5
Time: 6.2s
Precision: 64
\[\frac{\left(-b_2\right) + \sqrt{b_2 \cdot b_2 - a \cdot c}}{a}\]
\[\begin{array}{l} \mathbf{if}\;b_2 \le -3.5812949048043538 \cdot 10^{-96}:\\ \;\;\;\;\frac{1}{2} \cdot \frac{c}{b_2} - 2 \cdot \frac{b_2}{a}\\ \mathbf{elif}\;b_2 \le 7.99853652545151242 \cdot 10^{49}:\\ \;\;\;\;\frac{1}{\frac{a}{a \cdot c} \cdot \left(\left(-b_2\right) - \sqrt{b_2 \cdot b_2 - a \cdot c}\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{-1}{2} \cdot \frac{c}{b_2}\\ \end{array}\]
\frac{\left(-b_2\right) + \sqrt{b_2 \cdot b_2 - a \cdot c}}{a}
\begin{array}{l}
\mathbf{if}\;b_2 \le -3.5812949048043538 \cdot 10^{-96}:\\
\;\;\;\;\frac{1}{2} \cdot \frac{c}{b_2} - 2 \cdot \frac{b_2}{a}\\

\mathbf{elif}\;b_2 \le 7.99853652545151242 \cdot 10^{49}:\\
\;\;\;\;\frac{1}{\frac{a}{a \cdot c} \cdot \left(\left(-b_2\right) - \sqrt{b_2 \cdot b_2 - a \cdot c}\right)}\\

\mathbf{else}:\\
\;\;\;\;\frac{-1}{2} \cdot \frac{c}{b_2}\\

\end{array}
double f(double a, double b_2, double c) {
        double r21331 = b_2;
        double r21332 = -r21331;
        double r21333 = r21331 * r21331;
        double r21334 = a;
        double r21335 = c;
        double r21336 = r21334 * r21335;
        double r21337 = r21333 - r21336;
        double r21338 = sqrt(r21337);
        double r21339 = r21332 + r21338;
        double r21340 = r21339 / r21334;
        return r21340;
}

double f(double a, double b_2, double c) {
        double r21341 = b_2;
        double r21342 = -3.581294904804354e-96;
        bool r21343 = r21341 <= r21342;
        double r21344 = 0.5;
        double r21345 = c;
        double r21346 = r21345 / r21341;
        double r21347 = r21344 * r21346;
        double r21348 = 2.0;
        double r21349 = a;
        double r21350 = r21341 / r21349;
        double r21351 = r21348 * r21350;
        double r21352 = r21347 - r21351;
        double r21353 = 7.998536525451512e+49;
        bool r21354 = r21341 <= r21353;
        double r21355 = 1.0;
        double r21356 = r21349 * r21345;
        double r21357 = r21349 / r21356;
        double r21358 = -r21341;
        double r21359 = r21341 * r21341;
        double r21360 = r21359 - r21356;
        double r21361 = sqrt(r21360);
        double r21362 = r21358 - r21361;
        double r21363 = r21357 * r21362;
        double r21364 = r21355 / r21363;
        double r21365 = -0.5;
        double r21366 = r21365 * r21346;
        double r21367 = r21354 ? r21364 : r21366;
        double r21368 = r21343 ? r21352 : r21367;
        return r21368;
}

Error

Bits error versus a

Bits error versus b_2

Bits error versus c

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Derivation

  1. Split input into 3 regimes
  2. if b_2 < -3.581294904804354e-96

    1. Initial program 25.9

      \[\frac{\left(-b_2\right) + \sqrt{b_2 \cdot b_2 - a \cdot c}}{a}\]
    2. Taylor expanded around -inf 12.9

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \frac{c}{b_2} - 2 \cdot \frac{b_2}{a}}\]

    if -3.581294904804354e-96 < b_2 < 7.998536525451512e+49

    1. Initial program 24.5

      \[\frac{\left(-b_2\right) + \sqrt{b_2 \cdot b_2 - a \cdot c}}{a}\]
    2. Using strategy rm
    3. Applied flip-+26.7

      \[\leadsto \frac{\color{blue}{\frac{\left(-b_2\right) \cdot \left(-b_2\right) - \sqrt{b_2 \cdot b_2 - a \cdot c} \cdot \sqrt{b_2 \cdot b_2 - a \cdot c}}{\left(-b_2\right) - \sqrt{b_2 \cdot b_2 - a \cdot c}}}}{a}\]
    4. Simplified18.5

      \[\leadsto \frac{\frac{\color{blue}{0 + a \cdot c}}{\left(-b_2\right) - \sqrt{b_2 \cdot b_2 - a \cdot c}}}{a}\]
    5. Using strategy rm
    6. Applied *-un-lft-identity18.5

      \[\leadsto \frac{\frac{0 + a \cdot c}{\color{blue}{1 \cdot \left(\left(-b_2\right) - \sqrt{b_2 \cdot b_2 - a \cdot c}\right)}}}{a}\]
    7. Applied *-un-lft-identity18.5

      \[\leadsto \frac{\frac{\color{blue}{1 \cdot \left(0 + a \cdot c\right)}}{1 \cdot \left(\left(-b_2\right) - \sqrt{b_2 \cdot b_2 - a \cdot c}\right)}}{a}\]
    8. Applied times-frac18.5

      \[\leadsto \frac{\color{blue}{\frac{1}{1} \cdot \frac{0 + a \cdot c}{\left(-b_2\right) - \sqrt{b_2 \cdot b_2 - a \cdot c}}}}{a}\]
    9. Applied associate-/l*18.6

      \[\leadsto \color{blue}{\frac{\frac{1}{1}}{\frac{a}{\frac{0 + a \cdot c}{\left(-b_2\right) - \sqrt{b_2 \cdot b_2 - a \cdot c}}}}}\]
    10. Simplified18.4

      \[\leadsto \frac{\frac{1}{1}}{\color{blue}{\frac{a}{a \cdot c} \cdot \left(\left(-b_2\right) - \sqrt{b_2 \cdot b_2 - a \cdot c}\right)}}\]

    if 7.998536525451512e+49 < b_2

    1. Initial program 56.9

      \[\frac{\left(-b_2\right) + \sqrt{b_2 \cdot b_2 - a \cdot c}}{a}\]
    2. Taylor expanded around inf 4.0

      \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{c}{b_2}}\]
  3. Recombined 3 regimes into one program.
  4. Final simplification12.5

    \[\leadsto \begin{array}{l} \mathbf{if}\;b_2 \le -3.5812949048043538 \cdot 10^{-96}:\\ \;\;\;\;\frac{1}{2} \cdot \frac{c}{b_2} - 2 \cdot \frac{b_2}{a}\\ \mathbf{elif}\;b_2 \le 7.99853652545151242 \cdot 10^{49}:\\ \;\;\;\;\frac{1}{\frac{a}{a \cdot c} \cdot \left(\left(-b_2\right) - \sqrt{b_2 \cdot b_2 - a \cdot c}\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{-1}{2} \cdot \frac{c}{b_2}\\ \end{array}\]

Reproduce

herbie shell --seed 2020033 
(FPCore (a b_2 c)
  :name "quad2p (problem 3.2.1, positive)"
  :precision binary64
  (/ (+ (- b_2) (sqrt (- (* b_2 b_2) (* a c)))) a))