Quadratic roots, full range

Percentage Accurate: 53.1% → 85.2%
Time: 10.2s
Alternatives: 8
Speedup: 2.5×

Specification

?
\[\begin{array}{l} \\ \frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (/ (+ (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))) (* 2.0 a)))
double code(double a, double b, double c) {
	return (-b + sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a);
}
real(8) function code(a, b, c)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: c
    code = (-b + sqrt(((b * b) - ((4.0d0 * a) * c)))) / (2.0d0 * a)
end function
public static double code(double a, double b, double c) {
	return (-b + Math.sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a);
}
def code(a, b, c):
	return (-b + math.sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a)
function code(a, b, c)
	return Float64(Float64(Float64(-b) + sqrt(Float64(Float64(b * b) - Float64(Float64(4.0 * a) * c)))) / Float64(2.0 * a))
end
function tmp = code(a, b, c)
	tmp = (-b + sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a);
end
code[a_, b_, c_] := N[(N[((-b) + N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(4.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a}
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 8 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 53.1% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (/ (+ (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))) (* 2.0 a)))
double code(double a, double b, double c) {
	return (-b + sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a);
}
real(8) function code(a, b, c)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: c
    code = (-b + sqrt(((b * b) - ((4.0d0 * a) * c)))) / (2.0d0 * a)
end function
public static double code(double a, double b, double c) {
	return (-b + Math.sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a);
}
def code(a, b, c):
	return (-b + math.sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a)
function code(a, b, c)
	return Float64(Float64(Float64(-b) + sqrt(Float64(Float64(b * b) - Float64(Float64(4.0 * a) * c)))) / Float64(2.0 * a))
end
function tmp = code(a, b, c)
	tmp = (-b + sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a);
end
code[a_, b_, c_] := N[(N[((-b) + N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(4.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a}
\end{array}

Alternative 1: 85.2% accurate, 0.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq -5.2 \cdot 10^{+47}:\\ \;\;\;\;\mathsf{fma}\left(b, \frac{c}{b \cdot b}, \frac{b}{-a}\right)\\ \mathbf{elif}\;b \leq 4.5 \cdot 10^{-26}:\\ \;\;\;\;\frac{\sqrt{b \cdot b - c \cdot \left(a \cdot 4\right)} - b}{a \cdot 2}\\ \mathbf{else}:\\ \;\;\;\;-\frac{c}{b}\\ \end{array} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (if (<= b -5.2e+47)
   (fma b (/ c (* b b)) (/ b (- a)))
   (if (<= b 4.5e-26)
     (/ (- (sqrt (- (* b b) (* c (* a 4.0)))) b) (* a 2.0))
     (- (/ c b)))))
double code(double a, double b, double c) {
	double tmp;
	if (b <= -5.2e+47) {
		tmp = fma(b, (c / (b * b)), (b / -a));
	} else if (b <= 4.5e-26) {
		tmp = (sqrt(((b * b) - (c * (a * 4.0)))) - b) / (a * 2.0);
	} else {
		tmp = -(c / b);
	}
	return tmp;
}
function code(a, b, c)
	tmp = 0.0
	if (b <= -5.2e+47)
		tmp = fma(b, Float64(c / Float64(b * b)), Float64(b / Float64(-a)));
	elseif (b <= 4.5e-26)
		tmp = Float64(Float64(sqrt(Float64(Float64(b * b) - Float64(c * Float64(a * 4.0)))) - b) / Float64(a * 2.0));
	else
		tmp = Float64(-Float64(c / b));
	end
	return tmp
end
code[a_, b_, c_] := If[LessEqual[b, -5.2e+47], N[(b * N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] + N[(b / (-a)), $MachinePrecision]), $MachinePrecision], If[LessEqual[b, 4.5e-26], N[(N[(N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(c * N[(a * 4.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(a * 2.0), $MachinePrecision]), $MachinePrecision], (-N[(c / b), $MachinePrecision])]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b \leq -5.2 \cdot 10^{+47}:\\
\;\;\;\;\mathsf{fma}\left(b, \frac{c}{b \cdot b}, \frac{b}{-a}\right)\\

\mathbf{elif}\;b \leq 4.5 \cdot 10^{-26}:\\
\;\;\;\;\frac{\sqrt{b \cdot b - c \cdot \left(a \cdot 4\right)} - b}{a \cdot 2}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if b < -5.20000000000000007e47

    1. Initial program 71.1%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Add Preprocessing
    3. Taylor expanded in b around -inf

      \[\leadsto \color{blue}{-1 \cdot \left(b \cdot \left(-1 \cdot \frac{c}{{b}^{2}} + \frac{1}{a}\right)\right)} \]
    4. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \color{blue}{\mathsf{neg}\left(b \cdot \left(-1 \cdot \frac{c}{{b}^{2}} + \frac{1}{a}\right)\right)} \]
      2. distribute-rgt-inN/A

        \[\leadsto \mathsf{neg}\left(\color{blue}{\left(\left(-1 \cdot \frac{c}{{b}^{2}}\right) \cdot b + \frac{1}{a} \cdot b\right)}\right) \]
      3. distribute-neg-inN/A

        \[\leadsto \color{blue}{\left(\mathsf{neg}\left(\left(-1 \cdot \frac{c}{{b}^{2}}\right) \cdot b\right)\right) + \left(\mathsf{neg}\left(\frac{1}{a} \cdot b\right)\right)} \]
      4. associate-*l/N/A

        \[\leadsto \left(\mathsf{neg}\left(\left(-1 \cdot \frac{c}{{b}^{2}}\right) \cdot b\right)\right) + \left(\mathsf{neg}\left(\color{blue}{\frac{1 \cdot b}{a}}\right)\right) \]
      5. *-lft-identityN/A

        \[\leadsto \left(\mathsf{neg}\left(\left(-1 \cdot \frac{c}{{b}^{2}}\right) \cdot b\right)\right) + \left(\mathsf{neg}\left(\frac{\color{blue}{b}}{a}\right)\right) \]
      6. *-commutativeN/A

        \[\leadsto \left(\mathsf{neg}\left(\color{blue}{b \cdot \left(-1 \cdot \frac{c}{{b}^{2}}\right)}\right)\right) + \left(\mathsf{neg}\left(\frac{b}{a}\right)\right) \]
      7. mul-1-negN/A

        \[\leadsto \left(\mathsf{neg}\left(b \cdot \color{blue}{\left(\mathsf{neg}\left(\frac{c}{{b}^{2}}\right)\right)}\right)\right) + \left(\mathsf{neg}\left(\frac{b}{a}\right)\right) \]
      8. distribute-rgt-neg-outN/A

        \[\leadsto \left(\mathsf{neg}\left(\color{blue}{\left(\mathsf{neg}\left(b \cdot \frac{c}{{b}^{2}}\right)\right)}\right)\right) + \left(\mathsf{neg}\left(\frac{b}{a}\right)\right) \]
      9. remove-double-negN/A

        \[\leadsto \color{blue}{b \cdot \frac{c}{{b}^{2}}} + \left(\mathsf{neg}\left(\frac{b}{a}\right)\right) \]
      10. lower-fma.f64N/A

        \[\leadsto \color{blue}{\mathsf{fma}\left(b, \frac{c}{{b}^{2}}, \mathsf{neg}\left(\frac{b}{a}\right)\right)} \]
      11. lower-/.f64N/A

        \[\leadsto \mathsf{fma}\left(b, \color{blue}{\frac{c}{{b}^{2}}}, \mathsf{neg}\left(\frac{b}{a}\right)\right) \]
      12. unpow2N/A

        \[\leadsto \mathsf{fma}\left(b, \frac{c}{\color{blue}{b \cdot b}}, \mathsf{neg}\left(\frac{b}{a}\right)\right) \]
      13. lower-*.f64N/A

        \[\leadsto \mathsf{fma}\left(b, \frac{c}{\color{blue}{b \cdot b}}, \mathsf{neg}\left(\frac{b}{a}\right)\right) \]
      14. distribute-neg-frac2N/A

        \[\leadsto \mathsf{fma}\left(b, \frac{c}{b \cdot b}, \color{blue}{\frac{b}{\mathsf{neg}\left(a\right)}}\right) \]
      15. mul-1-negN/A

        \[\leadsto \mathsf{fma}\left(b, \frac{c}{b \cdot b}, \frac{b}{\color{blue}{-1 \cdot a}}\right) \]
      16. lower-/.f64N/A

        \[\leadsto \mathsf{fma}\left(b, \frac{c}{b \cdot b}, \color{blue}{\frac{b}{-1 \cdot a}}\right) \]
      17. mul-1-negN/A

        \[\leadsto \mathsf{fma}\left(b, \frac{c}{b \cdot b}, \frac{b}{\color{blue}{\mathsf{neg}\left(a\right)}}\right) \]
      18. lower-neg.f6498.8

        \[\leadsto \mathsf{fma}\left(b, \frac{c}{b \cdot b}, \frac{b}{\color{blue}{-a}}\right) \]
    5. Applied rewrites98.8%

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

    if -5.20000000000000007e47 < b < 4.4999999999999999e-26

    1. Initial program 79.8%

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

    if 4.4999999999999999e-26 < b

    1. Initial program 13.4%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Add Preprocessing
    3. Taylor expanded in b around inf

      \[\leadsto \color{blue}{-1 \cdot \frac{c}{b}} \]
    4. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \color{blue}{\mathsf{neg}\left(\frac{c}{b}\right)} \]
      2. distribute-neg-frac2N/A

        \[\leadsto \color{blue}{\frac{c}{\mathsf{neg}\left(b\right)}} \]
      3. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{c}{\mathsf{neg}\left(b\right)}} \]
      4. lower-neg.f6490.5

        \[\leadsto \frac{c}{\color{blue}{-b}} \]
    5. Applied rewrites90.5%

      \[\leadsto \color{blue}{\frac{c}{-b}} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification88.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b \leq -5.2 \cdot 10^{+47}:\\ \;\;\;\;\mathsf{fma}\left(b, \frac{c}{b \cdot b}, \frac{b}{-a}\right)\\ \mathbf{elif}\;b \leq 4.5 \cdot 10^{-26}:\\ \;\;\;\;\frac{\sqrt{b \cdot b - c \cdot \left(a \cdot 4\right)} - b}{a \cdot 2}\\ \mathbf{else}:\\ \;\;\;\;-\frac{c}{b}\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 85.1% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq -5.2 \cdot 10^{+47}:\\ \;\;\;\;\mathsf{fma}\left(b, \frac{c}{b \cdot b}, \frac{b}{-a}\right)\\ \mathbf{elif}\;b \leq 4.5 \cdot 10^{-26}:\\ \;\;\;\;\frac{-0.5}{a} \cdot \left(b - \sqrt{\mathsf{fma}\left(a, c \cdot -4, b \cdot b\right)}\right)\\ \mathbf{else}:\\ \;\;\;\;-\frac{c}{b}\\ \end{array} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (if (<= b -5.2e+47)
   (fma b (/ c (* b b)) (/ b (- a)))
   (if (<= b 4.5e-26)
     (* (/ -0.5 a) (- b (sqrt (fma a (* c -4.0) (* b b)))))
     (- (/ c b)))))
double code(double a, double b, double c) {
	double tmp;
	if (b <= -5.2e+47) {
		tmp = fma(b, (c / (b * b)), (b / -a));
	} else if (b <= 4.5e-26) {
		tmp = (-0.5 / a) * (b - sqrt(fma(a, (c * -4.0), (b * b))));
	} else {
		tmp = -(c / b);
	}
	return tmp;
}
function code(a, b, c)
	tmp = 0.0
	if (b <= -5.2e+47)
		tmp = fma(b, Float64(c / Float64(b * b)), Float64(b / Float64(-a)));
	elseif (b <= 4.5e-26)
		tmp = Float64(Float64(-0.5 / a) * Float64(b - sqrt(fma(a, Float64(c * -4.0), Float64(b * b)))));
	else
		tmp = Float64(-Float64(c / b));
	end
	return tmp
end
code[a_, b_, c_] := If[LessEqual[b, -5.2e+47], N[(b * N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] + N[(b / (-a)), $MachinePrecision]), $MachinePrecision], If[LessEqual[b, 4.5e-26], N[(N[(-0.5 / a), $MachinePrecision] * N[(b - N[Sqrt[N[(a * N[(c * -4.0), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], (-N[(c / b), $MachinePrecision])]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b \leq -5.2 \cdot 10^{+47}:\\
\;\;\;\;\mathsf{fma}\left(b, \frac{c}{b \cdot b}, \frac{b}{-a}\right)\\

\mathbf{elif}\;b \leq 4.5 \cdot 10^{-26}:\\
\;\;\;\;\frac{-0.5}{a} \cdot \left(b - \sqrt{\mathsf{fma}\left(a, c \cdot -4, b \cdot b\right)}\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if b < -5.20000000000000007e47

    1. Initial program 71.1%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Add Preprocessing
    3. Taylor expanded in b around -inf

      \[\leadsto \color{blue}{-1 \cdot \left(b \cdot \left(-1 \cdot \frac{c}{{b}^{2}} + \frac{1}{a}\right)\right)} \]
    4. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \color{blue}{\mathsf{neg}\left(b \cdot \left(-1 \cdot \frac{c}{{b}^{2}} + \frac{1}{a}\right)\right)} \]
      2. distribute-rgt-inN/A

        \[\leadsto \mathsf{neg}\left(\color{blue}{\left(\left(-1 \cdot \frac{c}{{b}^{2}}\right) \cdot b + \frac{1}{a} \cdot b\right)}\right) \]
      3. distribute-neg-inN/A

        \[\leadsto \color{blue}{\left(\mathsf{neg}\left(\left(-1 \cdot \frac{c}{{b}^{2}}\right) \cdot b\right)\right) + \left(\mathsf{neg}\left(\frac{1}{a} \cdot b\right)\right)} \]
      4. associate-*l/N/A

        \[\leadsto \left(\mathsf{neg}\left(\left(-1 \cdot \frac{c}{{b}^{2}}\right) \cdot b\right)\right) + \left(\mathsf{neg}\left(\color{blue}{\frac{1 \cdot b}{a}}\right)\right) \]
      5. *-lft-identityN/A

        \[\leadsto \left(\mathsf{neg}\left(\left(-1 \cdot \frac{c}{{b}^{2}}\right) \cdot b\right)\right) + \left(\mathsf{neg}\left(\frac{\color{blue}{b}}{a}\right)\right) \]
      6. *-commutativeN/A

        \[\leadsto \left(\mathsf{neg}\left(\color{blue}{b \cdot \left(-1 \cdot \frac{c}{{b}^{2}}\right)}\right)\right) + \left(\mathsf{neg}\left(\frac{b}{a}\right)\right) \]
      7. mul-1-negN/A

        \[\leadsto \left(\mathsf{neg}\left(b \cdot \color{blue}{\left(\mathsf{neg}\left(\frac{c}{{b}^{2}}\right)\right)}\right)\right) + \left(\mathsf{neg}\left(\frac{b}{a}\right)\right) \]
      8. distribute-rgt-neg-outN/A

        \[\leadsto \left(\mathsf{neg}\left(\color{blue}{\left(\mathsf{neg}\left(b \cdot \frac{c}{{b}^{2}}\right)\right)}\right)\right) + \left(\mathsf{neg}\left(\frac{b}{a}\right)\right) \]
      9. remove-double-negN/A

        \[\leadsto \color{blue}{b \cdot \frac{c}{{b}^{2}}} + \left(\mathsf{neg}\left(\frac{b}{a}\right)\right) \]
      10. lower-fma.f64N/A

        \[\leadsto \color{blue}{\mathsf{fma}\left(b, \frac{c}{{b}^{2}}, \mathsf{neg}\left(\frac{b}{a}\right)\right)} \]
      11. lower-/.f64N/A

        \[\leadsto \mathsf{fma}\left(b, \color{blue}{\frac{c}{{b}^{2}}}, \mathsf{neg}\left(\frac{b}{a}\right)\right) \]
      12. unpow2N/A

        \[\leadsto \mathsf{fma}\left(b, \frac{c}{\color{blue}{b \cdot b}}, \mathsf{neg}\left(\frac{b}{a}\right)\right) \]
      13. lower-*.f64N/A

        \[\leadsto \mathsf{fma}\left(b, \frac{c}{\color{blue}{b \cdot b}}, \mathsf{neg}\left(\frac{b}{a}\right)\right) \]
      14. distribute-neg-frac2N/A

        \[\leadsto \mathsf{fma}\left(b, \frac{c}{b \cdot b}, \color{blue}{\frac{b}{\mathsf{neg}\left(a\right)}}\right) \]
      15. mul-1-negN/A

        \[\leadsto \mathsf{fma}\left(b, \frac{c}{b \cdot b}, \frac{b}{\color{blue}{-1 \cdot a}}\right) \]
      16. lower-/.f64N/A

        \[\leadsto \mathsf{fma}\left(b, \frac{c}{b \cdot b}, \color{blue}{\frac{b}{-1 \cdot a}}\right) \]
      17. mul-1-negN/A

        \[\leadsto \mathsf{fma}\left(b, \frac{c}{b \cdot b}, \frac{b}{\color{blue}{\mathsf{neg}\left(a\right)}}\right) \]
      18. lower-neg.f6498.8

        \[\leadsto \mathsf{fma}\left(b, \frac{c}{b \cdot b}, \frac{b}{\color{blue}{-a}}\right) \]
    5. Applied rewrites98.8%

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

    if -5.20000000000000007e47 < b < 4.4999999999999999e-26

    1. Initial program 79.8%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Add Preprocessing
    3. Applied rewrites79.6%

      \[\leadsto \color{blue}{\frac{-0.5}{a} \cdot \left(b - \sqrt{\mathsf{fma}\left(a, -4 \cdot c, b \cdot b\right)}\right)} \]

    if 4.4999999999999999e-26 < b

    1. Initial program 13.4%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Add Preprocessing
    3. Taylor expanded in b around inf

      \[\leadsto \color{blue}{-1 \cdot \frac{c}{b}} \]
    4. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \color{blue}{\mathsf{neg}\left(\frac{c}{b}\right)} \]
      2. distribute-neg-frac2N/A

        \[\leadsto \color{blue}{\frac{c}{\mathsf{neg}\left(b\right)}} \]
      3. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{c}{\mathsf{neg}\left(b\right)}} \]
      4. lower-neg.f6490.5

        \[\leadsto \frac{c}{\color{blue}{-b}} \]
    5. Applied rewrites90.5%

      \[\leadsto \color{blue}{\frac{c}{-b}} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification88.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b \leq -5.2 \cdot 10^{+47}:\\ \;\;\;\;\mathsf{fma}\left(b, \frac{c}{b \cdot b}, \frac{b}{-a}\right)\\ \mathbf{elif}\;b \leq 4.5 \cdot 10^{-26}:\\ \;\;\;\;\frac{-0.5}{a} \cdot \left(b - \sqrt{\mathsf{fma}\left(a, c \cdot -4, b \cdot b\right)}\right)\\ \mathbf{else}:\\ \;\;\;\;-\frac{c}{b}\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 80.8% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq -8.6 \cdot 10^{-115}:\\ \;\;\;\;\frac{b}{-a}\\ \mathbf{elif}\;b \leq 2.8 \cdot 10^{-65}:\\ \;\;\;\;\frac{\sqrt{c \cdot \left(a \cdot -4\right)} - b}{a \cdot 2}\\ \mathbf{else}:\\ \;\;\;\;-\frac{c}{b}\\ \end{array} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (if (<= b -8.6e-115)
   (/ b (- a))
   (if (<= b 2.8e-65)
     (/ (- (sqrt (* c (* a -4.0))) b) (* a 2.0))
     (- (/ c b)))))
double code(double a, double b, double c) {
	double tmp;
	if (b <= -8.6e-115) {
		tmp = b / -a;
	} else if (b <= 2.8e-65) {
		tmp = (sqrt((c * (a * -4.0))) - b) / (a * 2.0);
	} else {
		tmp = -(c / b);
	}
	return tmp;
}
real(8) function code(a, b, c)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: c
    real(8) :: tmp
    if (b <= (-8.6d-115)) then
        tmp = b / -a
    else if (b <= 2.8d-65) then
        tmp = (sqrt((c * (a * (-4.0d0)))) - b) / (a * 2.0d0)
    else
        tmp = -(c / b)
    end if
    code = tmp
end function
public static double code(double a, double b, double c) {
	double tmp;
	if (b <= -8.6e-115) {
		tmp = b / -a;
	} else if (b <= 2.8e-65) {
		tmp = (Math.sqrt((c * (a * -4.0))) - b) / (a * 2.0);
	} else {
		tmp = -(c / b);
	}
	return tmp;
}
def code(a, b, c):
	tmp = 0
	if b <= -8.6e-115:
		tmp = b / -a
	elif b <= 2.8e-65:
		tmp = (math.sqrt((c * (a * -4.0))) - b) / (a * 2.0)
	else:
		tmp = -(c / b)
	return tmp
function code(a, b, c)
	tmp = 0.0
	if (b <= -8.6e-115)
		tmp = Float64(b / Float64(-a));
	elseif (b <= 2.8e-65)
		tmp = Float64(Float64(sqrt(Float64(c * Float64(a * -4.0))) - b) / Float64(a * 2.0));
	else
		tmp = Float64(-Float64(c / b));
	end
	return tmp
end
function tmp_2 = code(a, b, c)
	tmp = 0.0;
	if (b <= -8.6e-115)
		tmp = b / -a;
	elseif (b <= 2.8e-65)
		tmp = (sqrt((c * (a * -4.0))) - b) / (a * 2.0);
	else
		tmp = -(c / b);
	end
	tmp_2 = tmp;
end
code[a_, b_, c_] := If[LessEqual[b, -8.6e-115], N[(b / (-a)), $MachinePrecision], If[LessEqual[b, 2.8e-65], N[(N[(N[Sqrt[N[(c * N[(a * -4.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(a * 2.0), $MachinePrecision]), $MachinePrecision], (-N[(c / b), $MachinePrecision])]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b \leq -8.6 \cdot 10^{-115}:\\
\;\;\;\;\frac{b}{-a}\\

\mathbf{elif}\;b \leq 2.8 \cdot 10^{-65}:\\
\;\;\;\;\frac{\sqrt{c \cdot \left(a \cdot -4\right)} - b}{a \cdot 2}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if b < -8.6000000000000008e-115

    1. Initial program 78.2%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Add Preprocessing
    3. Taylor expanded in b around -inf

      \[\leadsto \color{blue}{-1 \cdot \frac{b}{a}} \]
    4. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \color{blue}{\mathsf{neg}\left(\frac{b}{a}\right)} \]
      2. distribute-neg-frac2N/A

        \[\leadsto \color{blue}{\frac{b}{\mathsf{neg}\left(a\right)}} \]
      3. mul-1-negN/A

        \[\leadsto \frac{b}{\color{blue}{-1 \cdot a}} \]
      4. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{b}{-1 \cdot a}} \]
      5. mul-1-negN/A

        \[\leadsto \frac{b}{\color{blue}{\mathsf{neg}\left(a\right)}} \]
      6. lower-neg.f6489.0

        \[\leadsto \frac{b}{\color{blue}{-a}} \]
    5. Applied rewrites89.0%

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

    if -8.6000000000000008e-115 < b < 2.8e-65

    1. Initial program 76.8%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Add Preprocessing
    3. Taylor expanded in b around 0

      \[\leadsto \frac{\left(\mathsf{neg}\left(b\right)\right) + \sqrt{\color{blue}{-4 \cdot \left(a \cdot c\right)}}}{2 \cdot a} \]
    4. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\right)\right) + \sqrt{\color{blue}{\left(a \cdot c\right) \cdot -4}}}{2 \cdot a} \]
      2. associate-*l*N/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\right)\right) + \sqrt{\color{blue}{a \cdot \left(c \cdot -4\right)}}}{2 \cdot a} \]
      3. *-commutativeN/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\right)\right) + \sqrt{a \cdot \color{blue}{\left(-4 \cdot c\right)}}}{2 \cdot a} \]
      4. lower-*.f64N/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\right)\right) + \sqrt{\color{blue}{a \cdot \left(-4 \cdot c\right)}}}{2 \cdot a} \]
      5. *-commutativeN/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\right)\right) + \sqrt{a \cdot \color{blue}{\left(c \cdot -4\right)}}}{2 \cdot a} \]
      6. lower-*.f6472.6

        \[\leadsto \frac{\left(-b\right) + \sqrt{a \cdot \color{blue}{\left(c \cdot -4\right)}}}{2 \cdot a} \]
    5. Applied rewrites72.6%

      \[\leadsto \frac{\left(-b\right) + \sqrt{\color{blue}{a \cdot \left(c \cdot -4\right)}}}{2 \cdot a} \]
    6. Step-by-step derivation
      1. lift-neg.f64N/A

        \[\leadsto \frac{\color{blue}{\left(\mathsf{neg}\left(b\right)\right)} + \sqrt{a \cdot \left(c \cdot -4\right)}}{2 \cdot a} \]
      2. lift-*.f64N/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\right)\right) + \sqrt{a \cdot \color{blue}{\left(c \cdot -4\right)}}}{2 \cdot a} \]
      3. lift-*.f64N/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\right)\right) + \sqrt{\color{blue}{a \cdot \left(c \cdot -4\right)}}}{2 \cdot a} \]
      4. lift-sqrt.f64N/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\right)\right) + \color{blue}{\sqrt{a \cdot \left(c \cdot -4\right)}}}{2 \cdot a} \]
      5. lift-+.f64N/A

        \[\leadsto \frac{\color{blue}{\left(\mathsf{neg}\left(b\right)\right) + \sqrt{a \cdot \left(c \cdot -4\right)}}}{2 \cdot a} \]
      6. lift-*.f64N/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\right)\right) + \sqrt{a \cdot \left(c \cdot -4\right)}}{\color{blue}{2 \cdot a}} \]
      7. lift-/.f6472.6

        \[\leadsto \color{blue}{\frac{\left(-b\right) + \sqrt{a \cdot \left(c \cdot -4\right)}}{2 \cdot a}} \]
      8. lift-+.f64N/A

        \[\leadsto \frac{\color{blue}{\left(\mathsf{neg}\left(b\right)\right) + \sqrt{a \cdot \left(c \cdot -4\right)}}}{2 \cdot a} \]
      9. +-commutativeN/A

        \[\leadsto \frac{\color{blue}{\sqrt{a \cdot \left(c \cdot -4\right)} + \left(\mathsf{neg}\left(b\right)\right)}}{2 \cdot a} \]
      10. lift-neg.f64N/A

        \[\leadsto \frac{\sqrt{a \cdot \left(c \cdot -4\right)} + \color{blue}{\left(\mathsf{neg}\left(b\right)\right)}}{2 \cdot a} \]
      11. unsub-negN/A

        \[\leadsto \frac{\color{blue}{\sqrt{a \cdot \left(c \cdot -4\right)} - b}}{2 \cdot a} \]
      12. lower--.f6472.6

        \[\leadsto \frac{\color{blue}{\sqrt{a \cdot \left(c \cdot -4\right)} - b}}{2 \cdot a} \]
      13. lift-*.f64N/A

        \[\leadsto \frac{\sqrt{\color{blue}{a \cdot \left(c \cdot -4\right)}} - b}{2 \cdot a} \]
      14. *-commutativeN/A

        \[\leadsto \frac{\sqrt{\color{blue}{\left(c \cdot -4\right) \cdot a}} - b}{2 \cdot a} \]
      15. lift-*.f64N/A

        \[\leadsto \frac{\sqrt{\color{blue}{\left(c \cdot -4\right)} \cdot a} - b}{2 \cdot a} \]
      16. associate-*l*N/A

        \[\leadsto \frac{\sqrt{\color{blue}{c \cdot \left(-4 \cdot a\right)}} - b}{2 \cdot a} \]
      17. lower-*.f64N/A

        \[\leadsto \frac{\sqrt{\color{blue}{c \cdot \left(-4 \cdot a\right)}} - b}{2 \cdot a} \]
      18. lower-*.f6472.6

        \[\leadsto \frac{\sqrt{c \cdot \color{blue}{\left(-4 \cdot a\right)}} - b}{2 \cdot a} \]
      19. lift-*.f64N/A

        \[\leadsto \frac{\sqrt{c \cdot \left(-4 \cdot a\right)} - b}{\color{blue}{2 \cdot a}} \]
      20. *-commutativeN/A

        \[\leadsto \frac{\sqrt{c \cdot \left(-4 \cdot a\right)} - b}{\color{blue}{a \cdot 2}} \]
      21. lower-*.f6472.6

        \[\leadsto \frac{\sqrt{c \cdot \left(-4 \cdot a\right)} - b}{\color{blue}{a \cdot 2}} \]
    7. Applied rewrites72.6%

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

    if 2.8e-65 < b

    1. Initial program 17.8%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Add Preprocessing
    3. Taylor expanded in b around inf

      \[\leadsto \color{blue}{-1 \cdot \frac{c}{b}} \]
    4. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \color{blue}{\mathsf{neg}\left(\frac{c}{b}\right)} \]
      2. distribute-neg-frac2N/A

        \[\leadsto \color{blue}{\frac{c}{\mathsf{neg}\left(b\right)}} \]
      3. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{c}{\mathsf{neg}\left(b\right)}} \]
      4. lower-neg.f6485.4

        \[\leadsto \frac{c}{\color{blue}{-b}} \]
    5. Applied rewrites85.4%

      \[\leadsto \color{blue}{\frac{c}{-b}} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification83.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b \leq -8.6 \cdot 10^{-115}:\\ \;\;\;\;\frac{b}{-a}\\ \mathbf{elif}\;b \leq 2.8 \cdot 10^{-65}:\\ \;\;\;\;\frac{\sqrt{c \cdot \left(a \cdot -4\right)} - b}{a \cdot 2}\\ \mathbf{else}:\\ \;\;\;\;-\frac{c}{b}\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 80.8% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq -8.6 \cdot 10^{-115}:\\ \;\;\;\;\frac{b}{-a}\\ \mathbf{elif}\;b \leq 2.8 \cdot 10^{-65}:\\ \;\;\;\;\frac{-0.5}{a} \cdot \left(b - \sqrt{a \cdot \left(c \cdot -4\right)}\right)\\ \mathbf{else}:\\ \;\;\;\;-\frac{c}{b}\\ \end{array} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (if (<= b -8.6e-115)
   (/ b (- a))
   (if (<= b 2.8e-65)
     (* (/ -0.5 a) (- b (sqrt (* a (* c -4.0)))))
     (- (/ c b)))))
double code(double a, double b, double c) {
	double tmp;
	if (b <= -8.6e-115) {
		tmp = b / -a;
	} else if (b <= 2.8e-65) {
		tmp = (-0.5 / a) * (b - sqrt((a * (c * -4.0))));
	} else {
		tmp = -(c / b);
	}
	return tmp;
}
real(8) function code(a, b, c)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: c
    real(8) :: tmp
    if (b <= (-8.6d-115)) then
        tmp = b / -a
    else if (b <= 2.8d-65) then
        tmp = ((-0.5d0) / a) * (b - sqrt((a * (c * (-4.0d0)))))
    else
        tmp = -(c / b)
    end if
    code = tmp
end function
public static double code(double a, double b, double c) {
	double tmp;
	if (b <= -8.6e-115) {
		tmp = b / -a;
	} else if (b <= 2.8e-65) {
		tmp = (-0.5 / a) * (b - Math.sqrt((a * (c * -4.0))));
	} else {
		tmp = -(c / b);
	}
	return tmp;
}
def code(a, b, c):
	tmp = 0
	if b <= -8.6e-115:
		tmp = b / -a
	elif b <= 2.8e-65:
		tmp = (-0.5 / a) * (b - math.sqrt((a * (c * -4.0))))
	else:
		tmp = -(c / b)
	return tmp
function code(a, b, c)
	tmp = 0.0
	if (b <= -8.6e-115)
		tmp = Float64(b / Float64(-a));
	elseif (b <= 2.8e-65)
		tmp = Float64(Float64(-0.5 / a) * Float64(b - sqrt(Float64(a * Float64(c * -4.0)))));
	else
		tmp = Float64(-Float64(c / b));
	end
	return tmp
end
function tmp_2 = code(a, b, c)
	tmp = 0.0;
	if (b <= -8.6e-115)
		tmp = b / -a;
	elseif (b <= 2.8e-65)
		tmp = (-0.5 / a) * (b - sqrt((a * (c * -4.0))));
	else
		tmp = -(c / b);
	end
	tmp_2 = tmp;
end
code[a_, b_, c_] := If[LessEqual[b, -8.6e-115], N[(b / (-a)), $MachinePrecision], If[LessEqual[b, 2.8e-65], N[(N[(-0.5 / a), $MachinePrecision] * N[(b - N[Sqrt[N[(a * N[(c * -4.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], (-N[(c / b), $MachinePrecision])]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b \leq -8.6 \cdot 10^{-115}:\\
\;\;\;\;\frac{b}{-a}\\

\mathbf{elif}\;b \leq 2.8 \cdot 10^{-65}:\\
\;\;\;\;\frac{-0.5}{a} \cdot \left(b - \sqrt{a \cdot \left(c \cdot -4\right)}\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if b < -8.6000000000000008e-115

    1. Initial program 78.2%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Add Preprocessing
    3. Taylor expanded in b around -inf

      \[\leadsto \color{blue}{-1 \cdot \frac{b}{a}} \]
    4. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \color{blue}{\mathsf{neg}\left(\frac{b}{a}\right)} \]
      2. distribute-neg-frac2N/A

        \[\leadsto \color{blue}{\frac{b}{\mathsf{neg}\left(a\right)}} \]
      3. mul-1-negN/A

        \[\leadsto \frac{b}{\color{blue}{-1 \cdot a}} \]
      4. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{b}{-1 \cdot a}} \]
      5. mul-1-negN/A

        \[\leadsto \frac{b}{\color{blue}{\mathsf{neg}\left(a\right)}} \]
      6. lower-neg.f6489.0

        \[\leadsto \frac{b}{\color{blue}{-a}} \]
    5. Applied rewrites89.0%

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

    if -8.6000000000000008e-115 < b < 2.8e-65

    1. Initial program 76.8%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Add Preprocessing
    3. Applied rewrites76.7%

      \[\leadsto \color{blue}{\frac{-0.5}{a} \cdot \left(b - \sqrt{\mathsf{fma}\left(a, -4 \cdot c, b \cdot b\right)}\right)} \]
    4. Taylor expanded in a around inf

      \[\leadsto \frac{\frac{-1}{2}}{a} \cdot \left(b - \sqrt{\color{blue}{-4 \cdot \left(a \cdot c\right)}}\right) \]
    5. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{\frac{-1}{2}}{a} \cdot \left(b - \sqrt{\color{blue}{\left(a \cdot c\right) \cdot -4}}\right) \]
      2. rem-square-sqrtN/A

        \[\leadsto \frac{\frac{-1}{2}}{a} \cdot \left(b - \sqrt{\left(a \cdot c\right) \cdot \color{blue}{\left(\sqrt{-4} \cdot \sqrt{-4}\right)}}\right) \]
      3. unpow2N/A

        \[\leadsto \frac{\frac{-1}{2}}{a} \cdot \left(b - \sqrt{\left(a \cdot c\right) \cdot \color{blue}{{\left(\sqrt{-4}\right)}^{2}}}\right) \]
      4. associate-*r*N/A

        \[\leadsto \frac{\frac{-1}{2}}{a} \cdot \left(b - \sqrt{\color{blue}{a \cdot \left(c \cdot {\left(\sqrt{-4}\right)}^{2}\right)}}\right) \]
      5. *-commutativeN/A

        \[\leadsto \frac{\frac{-1}{2}}{a} \cdot \left(b - \sqrt{a \cdot \color{blue}{\left({\left(\sqrt{-4}\right)}^{2} \cdot c\right)}}\right) \]
      6. unpow2N/A

        \[\leadsto \frac{\frac{-1}{2}}{a} \cdot \left(b - \sqrt{a \cdot \left(\color{blue}{\left(\sqrt{-4} \cdot \sqrt{-4}\right)} \cdot c\right)}\right) \]
      7. rem-square-sqrtN/A

        \[\leadsto \frac{\frac{-1}{2}}{a} \cdot \left(b - \sqrt{a \cdot \left(\color{blue}{-4} \cdot c\right)}\right) \]
      8. lower-*.f64N/A

        \[\leadsto \frac{\frac{-1}{2}}{a} \cdot \left(b - \sqrt{\color{blue}{a \cdot \left(-4 \cdot c\right)}}\right) \]
      9. *-commutativeN/A

        \[\leadsto \frac{\frac{-1}{2}}{a} \cdot \left(b - \sqrt{a \cdot \color{blue}{\left(c \cdot -4\right)}}\right) \]
      10. lower-*.f6472.5

        \[\leadsto \frac{-0.5}{a} \cdot \left(b - \sqrt{a \cdot \color{blue}{\left(c \cdot -4\right)}}\right) \]
    6. Applied rewrites72.5%

      \[\leadsto \frac{-0.5}{a} \cdot \left(b - \sqrt{\color{blue}{a \cdot \left(c \cdot -4\right)}}\right) \]

    if 2.8e-65 < b

    1. Initial program 17.8%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Add Preprocessing
    3. Taylor expanded in b around inf

      \[\leadsto \color{blue}{-1 \cdot \frac{c}{b}} \]
    4. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \color{blue}{\mathsf{neg}\left(\frac{c}{b}\right)} \]
      2. distribute-neg-frac2N/A

        \[\leadsto \color{blue}{\frac{c}{\mathsf{neg}\left(b\right)}} \]
      3. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{c}{\mathsf{neg}\left(b\right)}} \]
      4. lower-neg.f6485.4

        \[\leadsto \frac{c}{\color{blue}{-b}} \]
    5. Applied rewrites85.4%

      \[\leadsto \color{blue}{\frac{c}{-b}} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification83.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b \leq -8.6 \cdot 10^{-115}:\\ \;\;\;\;\frac{b}{-a}\\ \mathbf{elif}\;b \leq 2.8 \cdot 10^{-65}:\\ \;\;\;\;\frac{-0.5}{a} \cdot \left(b - \sqrt{a \cdot \left(c \cdot -4\right)}\right)\\ \mathbf{else}:\\ \;\;\;\;-\frac{c}{b}\\ \end{array} \]
  5. Add Preprocessing

Alternative 5: 67.2% accurate, 2.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq -2 \cdot 10^{-311}:\\ \;\;\;\;\frac{b}{-a}\\ \mathbf{else}:\\ \;\;\;\;-\frac{c}{b}\\ \end{array} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (if (<= b -2e-311) (/ b (- a)) (- (/ c b))))
double code(double a, double b, double c) {
	double tmp;
	if (b <= -2e-311) {
		tmp = b / -a;
	} else {
		tmp = -(c / b);
	}
	return tmp;
}
real(8) function code(a, b, c)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: c
    real(8) :: tmp
    if (b <= (-2d-311)) then
        tmp = b / -a
    else
        tmp = -(c / b)
    end if
    code = tmp
end function
public static double code(double a, double b, double c) {
	double tmp;
	if (b <= -2e-311) {
		tmp = b / -a;
	} else {
		tmp = -(c / b);
	}
	return tmp;
}
def code(a, b, c):
	tmp = 0
	if b <= -2e-311:
		tmp = b / -a
	else:
		tmp = -(c / b)
	return tmp
function code(a, b, c)
	tmp = 0.0
	if (b <= -2e-311)
		tmp = Float64(b / Float64(-a));
	else
		tmp = Float64(-Float64(c / b));
	end
	return tmp
end
function tmp_2 = code(a, b, c)
	tmp = 0.0;
	if (b <= -2e-311)
		tmp = b / -a;
	else
		tmp = -(c / b);
	end
	tmp_2 = tmp;
end
code[a_, b_, c_] := If[LessEqual[b, -2e-311], N[(b / (-a)), $MachinePrecision], (-N[(c / b), $MachinePrecision])]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b \leq -2 \cdot 10^{-311}:\\
\;\;\;\;\frac{b}{-a}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if b < -1.9999999999999e-311

    1. Initial program 79.1%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Add Preprocessing
    3. Taylor expanded in b around -inf

      \[\leadsto \color{blue}{-1 \cdot \frac{b}{a}} \]
    4. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \color{blue}{\mathsf{neg}\left(\frac{b}{a}\right)} \]
      2. distribute-neg-frac2N/A

        \[\leadsto \color{blue}{\frac{b}{\mathsf{neg}\left(a\right)}} \]
      3. mul-1-negN/A

        \[\leadsto \frac{b}{\color{blue}{-1 \cdot a}} \]
      4. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{b}{-1 \cdot a}} \]
      5. mul-1-negN/A

        \[\leadsto \frac{b}{\color{blue}{\mathsf{neg}\left(a\right)}} \]
      6. lower-neg.f6472.8

        \[\leadsto \frac{b}{\color{blue}{-a}} \]
    5. Applied rewrites72.8%

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

    if -1.9999999999999e-311 < b

    1. Initial program 32.3%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Add Preprocessing
    3. Taylor expanded in b around inf

      \[\leadsto \color{blue}{-1 \cdot \frac{c}{b}} \]
    4. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \color{blue}{\mathsf{neg}\left(\frac{c}{b}\right)} \]
      2. distribute-neg-frac2N/A

        \[\leadsto \color{blue}{\frac{c}{\mathsf{neg}\left(b\right)}} \]
      3. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{c}{\mathsf{neg}\left(b\right)}} \]
      4. lower-neg.f6467.0

        \[\leadsto \frac{c}{\color{blue}{-b}} \]
    5. Applied rewrites67.0%

      \[\leadsto \color{blue}{\frac{c}{-b}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification70.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b \leq -2 \cdot 10^{-311}:\\ \;\;\;\;\frac{b}{-a}\\ \mathbf{else}:\\ \;\;\;\;-\frac{c}{b}\\ \end{array} \]
  5. Add Preprocessing

Alternative 6: 43.3% accurate, 2.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq 2300:\\ \;\;\;\;\frac{b}{-a}\\ \mathbf{else}:\\ \;\;\;\;\frac{c}{b}\\ \end{array} \end{array} \]
(FPCore (a b c) :precision binary64 (if (<= b 2300.0) (/ b (- a)) (/ c b)))
double code(double a, double b, double c) {
	double tmp;
	if (b <= 2300.0) {
		tmp = b / -a;
	} else {
		tmp = c / b;
	}
	return tmp;
}
real(8) function code(a, b, c)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: c
    real(8) :: tmp
    if (b <= 2300.0d0) then
        tmp = b / -a
    else
        tmp = c / b
    end if
    code = tmp
end function
public static double code(double a, double b, double c) {
	double tmp;
	if (b <= 2300.0) {
		tmp = b / -a;
	} else {
		tmp = c / b;
	}
	return tmp;
}
def code(a, b, c):
	tmp = 0
	if b <= 2300.0:
		tmp = b / -a
	else:
		tmp = c / b
	return tmp
function code(a, b, c)
	tmp = 0.0
	if (b <= 2300.0)
		tmp = Float64(b / Float64(-a));
	else
		tmp = Float64(c / b);
	end
	return tmp
end
function tmp_2 = code(a, b, c)
	tmp = 0.0;
	if (b <= 2300.0)
		tmp = b / -a;
	else
		tmp = c / b;
	end
	tmp_2 = tmp;
end
code[a_, b_, c_] := If[LessEqual[b, 2300.0], N[(b / (-a)), $MachinePrecision], N[(c / b), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b \leq 2300:\\
\;\;\;\;\frac{b}{-a}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if b < 2300

    1. Initial program 74.4%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Add Preprocessing
    3. Taylor expanded in b around -inf

      \[\leadsto \color{blue}{-1 \cdot \frac{b}{a}} \]
    4. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \color{blue}{\mathsf{neg}\left(\frac{b}{a}\right)} \]
      2. distribute-neg-frac2N/A

        \[\leadsto \color{blue}{\frac{b}{\mathsf{neg}\left(a\right)}} \]
      3. mul-1-negN/A

        \[\leadsto \frac{b}{\color{blue}{-1 \cdot a}} \]
      4. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{b}{-1 \cdot a}} \]
      5. mul-1-negN/A

        \[\leadsto \frac{b}{\color{blue}{\mathsf{neg}\left(a\right)}} \]
      6. lower-neg.f6455.4

        \[\leadsto \frac{b}{\color{blue}{-a}} \]
    5. Applied rewrites55.4%

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

    if 2300 < b

    1. Initial program 12.8%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Add Preprocessing
    3. Applied rewrites3.7%

      \[\leadsto \color{blue}{\frac{0.5}{\frac{1}{b + \sqrt{\mathsf{fma}\left(a, -4 \cdot c, b \cdot b\right)}} \cdot a}} \]
    4. Taylor expanded in b around -inf

      \[\leadsto \color{blue}{\frac{c}{b}} \]
    5. Step-by-step derivation
      1. lower-/.f6430.3

        \[\leadsto \color{blue}{\frac{c}{b}} \]
    6. Applied rewrites30.3%

      \[\leadsto \color{blue}{\frac{c}{b}} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 7: 10.8% accurate, 4.2× speedup?

\[\begin{array}{l} \\ \frac{c}{b} \end{array} \]
(FPCore (a b c) :precision binary64 (/ c b))
double code(double a, double b, double c) {
	return c / b;
}
real(8) function code(a, b, c)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: c
    code = c / b
end function
public static double code(double a, double b, double c) {
	return c / b;
}
def code(a, b, c):
	return c / b
function code(a, b, c)
	return Float64(c / b)
end
function tmp = code(a, b, c)
	tmp = c / b;
end
code[a_, b_, c_] := N[(c / b), $MachinePrecision]
\begin{array}{l}

\\
\frac{c}{b}
\end{array}
Derivation
  1. Initial program 58.0%

    \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
  2. Add Preprocessing
  3. Applied rewrites34.8%

    \[\leadsto \color{blue}{\frac{0.5}{\frac{1}{b + \sqrt{\mathsf{fma}\left(a, -4 \cdot c, b \cdot b\right)}} \cdot a}} \]
  4. Taylor expanded in b around -inf

    \[\leadsto \color{blue}{\frac{c}{b}} \]
  5. Step-by-step derivation
    1. lower-/.f6410.3

      \[\leadsto \color{blue}{\frac{c}{b}} \]
  6. Applied rewrites10.3%

    \[\leadsto \color{blue}{\frac{c}{b}} \]
  7. Add Preprocessing

Alternative 8: 2.5% accurate, 4.2× speedup?

\[\begin{array}{l} \\ \frac{b}{a} \end{array} \]
(FPCore (a b c) :precision binary64 (/ b a))
double code(double a, double b, double c) {
	return b / a;
}
real(8) function code(a, b, c)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: c
    code = b / a
end function
public static double code(double a, double b, double c) {
	return b / a;
}
def code(a, b, c):
	return b / a
function code(a, b, c)
	return Float64(b / a)
end
function tmp = code(a, b, c)
	tmp = b / a;
end
code[a_, b_, c_] := N[(b / a), $MachinePrecision]
\begin{array}{l}

\\
\frac{b}{a}
\end{array}
Derivation
  1. Initial program 58.0%

    \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
  2. Add Preprocessing
  3. Applied rewrites34.8%

    \[\leadsto \color{blue}{\frac{0.5}{\frac{1}{b + \sqrt{\mathsf{fma}\left(a, -4 \cdot c, b \cdot b\right)}} \cdot a}} \]
  4. Taylor expanded in b around inf

    \[\leadsto \color{blue}{\frac{b}{a}} \]
  5. Step-by-step derivation
    1. lower-/.f642.2

      \[\leadsto \color{blue}{\frac{b}{a}} \]
  6. Applied rewrites2.2%

    \[\leadsto \color{blue}{\frac{b}{a}} \]
  7. Add Preprocessing

Reproduce

?
herbie shell --seed 2024219 
(FPCore (a b c)
  :name "Quadratic roots, full range"
  :precision binary64
  (/ (+ (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))) (* 2.0 a)))