Average Error: 28.7 → 0.4
Time: 4.5s
Precision: 64
\[1.05367121277235087 \cdot 10^{-8} \lt a \lt 94906265.6242515594 \land 1.05367121277235087 \cdot 10^{-8} \lt b \lt 94906265.6242515594 \land 1.05367121277235087 \cdot 10^{-8} \lt c \lt 94906265.6242515594\]
\[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a}\]
↓
\[\frac{4 \cdot a}{\left(2 \cdot a\right) \cdot \left(\frac{-b}{c} - \frac{\sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{c}\right)}\]
\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a}
↓
\frac{4 \cdot a}{\left(2 \cdot a\right) \cdot \left(\frac{-b}{c} - \frac{\sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{c}\right)}
double code(double a, double b, double c) {
	return ((-b + sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a));
}
↓
double code(double a, double b, double c) {
	return ((4.0 * a) / ((2.0 * a) * ((-b / c) - (sqrt(((b * b) - ((4.0 * a) * c))) / c))));
}

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

Derivation

  1. Initial program 28.7

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

  3. Applied flip-+28.8

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

  4. Simplified0.4

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

  6. Applied associate-*r*0.4

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

  7. Applied associate-/l*0.4

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

  8. Applied associate-/l/0.4

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

  10. Applied div-sub0.4

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

  11. Final simplification0.4

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

Reproduce

herbie shell --seed 2020071 
(FPCore (a b c)
  :name "Quadratic roots, narrow range"
  :precision binary64
  :pre (and (< 1.0536712127723509e-08 a 94906265.62425156) (< 1.0536712127723509e-08 b 94906265.62425156) (< 1.0536712127723509e-08 c 94906265.62425156))
  (/ (+ (- b) (sqrt (- (* b b) (* (* 4 a) c)))) (* 2 a)))