Average Error: 34.2 → 10.0
Time: 8.5s
Precision: 64
\[\frac{\left(-b\right) + \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a}\]
\[\begin{array}{l} \mathbf{if}\;b \le -8.55528137777049654 \cdot 10^{140}:\\ \;\;\;\;1 \cdot \left(\frac{c}{b} - \frac{b}{a}\right)\\ \mathbf{elif}\;b \le 5.08374808794434102 \cdot 10^{-70}:\\ \;\;\;\;\sqrt{\frac{\sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)} - b}{2}} \cdot \frac{\sqrt{\frac{\sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)} - b}{2}}}{a}\\ \mathbf{else}:\\ \;\;\;\;-1 \cdot \frac{c}{b}\\ \end{array}\]
\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 -8.55528137777049654 \cdot 10^{140}:\\
\;\;\;\;1 \cdot \left(\frac{c}{b} - \frac{b}{a}\right)\\

\mathbf{elif}\;b \le 5.08374808794434102 \cdot 10^{-70}:\\
\;\;\;\;\sqrt{\frac{\sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)} - b}{2}} \cdot \frac{\sqrt{\frac{\sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)} - b}{2}}}{a}\\

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

\end{array}
double f(double a, double b, double c) {
        double r68279 = b;
        double r68280 = -r68279;
        double r68281 = r68279 * r68279;
        double r68282 = 4.0;
        double r68283 = a;
        double r68284 = c;
        double r68285 = r68283 * r68284;
        double r68286 = r68282 * r68285;
        double r68287 = r68281 - r68286;
        double r68288 = sqrt(r68287);
        double r68289 = r68280 + r68288;
        double r68290 = 2.0;
        double r68291 = r68290 * r68283;
        double r68292 = r68289 / r68291;
        return r68292;
}

double f(double a, double b, double c) {
        double r68293 = b;
        double r68294 = -8.555281377770497e+140;
        bool r68295 = r68293 <= r68294;
        double r68296 = 1.0;
        double r68297 = c;
        double r68298 = r68297 / r68293;
        double r68299 = a;
        double r68300 = r68293 / r68299;
        double r68301 = r68298 - r68300;
        double r68302 = r68296 * r68301;
        double r68303 = 5.083748087944341e-70;
        bool r68304 = r68293 <= r68303;
        double r68305 = r68293 * r68293;
        double r68306 = 4.0;
        double r68307 = r68299 * r68297;
        double r68308 = r68306 * r68307;
        double r68309 = r68305 - r68308;
        double r68310 = sqrt(r68309);
        double r68311 = r68310 - r68293;
        double r68312 = 2.0;
        double r68313 = r68311 / r68312;
        double r68314 = sqrt(r68313);
        double r68315 = r68314 / r68299;
        double r68316 = r68314 * r68315;
        double r68317 = -1.0;
        double r68318 = r68317 * r68298;
        double r68319 = r68304 ? r68316 : r68318;
        double r68320 = r68295 ? r68302 : r68319;
        return r68320;
}

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

Original34.2
Target21.1
Herbie10.0
\[\begin{array}{l} \mathbf{if}\;b \lt 0.0:\\ \;\;\;\;\frac{\left(-b\right) + \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a}\\ \mathbf{else}:\\ \;\;\;\;\frac{c}{a \cdot \frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a}}\\ \end{array}\]

Derivation

  1. Split input into 3 regimes
  2. if b < -8.555281377770497e+140

    1. Initial program 58.5

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a}\]
    2. Simplified58.5

      \[\leadsto \color{blue}{\frac{\frac{\sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)} - b}{2}}{a}}\]
    3. Taylor expanded around -inf 2.4

      \[\leadsto \color{blue}{1 \cdot \frac{c}{b} - 1 \cdot \frac{b}{a}}\]
    4. Simplified2.4

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

    if -8.555281377770497e+140 < b < 5.083748087944341e-70

    1. Initial program 12.5

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a}\]
    2. Simplified12.5

      \[\leadsto \color{blue}{\frac{\frac{\sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)} - b}{2}}{a}}\]
    3. Using strategy rm
    4. Applied *-un-lft-identity12.5

      \[\leadsto \frac{\frac{\sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)} - b}{2}}{\color{blue}{1 \cdot a}}\]
    5. Applied add-sqr-sqrt13.0

      \[\leadsto \frac{\color{blue}{\sqrt{\frac{\sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)} - b}{2}} \cdot \sqrt{\frac{\sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)} - b}{2}}}}{1 \cdot a}\]
    6. Applied times-frac13.0

      \[\leadsto \color{blue}{\frac{\sqrt{\frac{\sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)} - b}{2}}}{1} \cdot \frac{\sqrt{\frac{\sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)} - b}{2}}}{a}}\]
    7. Simplified13.0

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

    if 5.083748087944341e-70 < b

    1. Initial program 53.1

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a}\]
    2. Simplified53.1

      \[\leadsto \color{blue}{\frac{\frac{\sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)} - b}{2}}{a}}\]
    3. Taylor expanded around inf 8.7

      \[\leadsto \color{blue}{-1 \cdot \frac{c}{b}}\]
  3. Recombined 3 regimes into one program.
  4. Final simplification10.0

    \[\leadsto \begin{array}{l} \mathbf{if}\;b \le -8.55528137777049654 \cdot 10^{140}:\\ \;\;\;\;1 \cdot \left(\frac{c}{b} - \frac{b}{a}\right)\\ \mathbf{elif}\;b \le 5.08374808794434102 \cdot 10^{-70}:\\ \;\;\;\;\sqrt{\frac{\sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)} - b}{2}} \cdot \frac{\sqrt{\frac{\sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)} - b}{2}}}{a}\\ \mathbf{else}:\\ \;\;\;\;-1 \cdot \frac{c}{b}\\ \end{array}\]

Reproduce

herbie shell --seed 2020046 +o rules:numerics
(FPCore (a b c)
  :name "quadp (p42, positive)"
  :precision binary64

  :herbie-target
  (if (< b 0.0) (/ (+ (- b) (sqrt (- (* b b) (* 4 (* a c))))) (* 2 a)) (/ c (* a (/ (- (- b) (sqrt (- (* b b) (* 4 (* a c))))) (* 2 a)))))

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