Quadratic roots, full range

Percentage Accurate: 52.5% → 85.1%
Time: 12.1s
Alternatives: 8
Speedup: 19.1×

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: 52.5% 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: 85.1% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq -2.15 \cdot 10^{+130}:\\ \;\;\;\;\frac{-b}{a}\\ \mathbf{elif}\;b \leq 3.1 \cdot 10^{-8}:\\ \;\;\;\;\frac{\sqrt{b \cdot b - \left(a \cdot 4\right) \cdot c} - b}{a \cdot 2}\\ \mathbf{else}:\\ \;\;\;\;\frac{-c}{b}\\ \end{array} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (if (<= b -2.15e+130)
   (/ (- b) a)
   (if (<= b 3.1e-8)
     (/ (- (sqrt (- (* b b) (* (* a 4.0) c))) b) (* a 2.0))
     (/ (- c) b))))
double code(double a, double b, double c) {
	double tmp;
	if (b <= -2.15e+130) {
		tmp = -b / a;
	} else if (b <= 3.1e-8) {
		tmp = (sqrt(((b * b) - ((a * 4.0) * c))) - 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 <= (-2.15d+130)) then
        tmp = -b / a
    else if (b <= 3.1d-8) then
        tmp = (sqrt(((b * b) - ((a * 4.0d0) * c))) - 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 <= -2.15e+130) {
		tmp = -b / a;
	} else if (b <= 3.1e-8) {
		tmp = (Math.sqrt(((b * b) - ((a * 4.0) * c))) - b) / (a * 2.0);
	} else {
		tmp = -c / b;
	}
	return tmp;
}
def code(a, b, c):
	tmp = 0
	if b <= -2.15e+130:
		tmp = -b / a
	elif b <= 3.1e-8:
		tmp = (math.sqrt(((b * b) - ((a * 4.0) * c))) - b) / (a * 2.0)
	else:
		tmp = -c / b
	return tmp
function code(a, b, c)
	tmp = 0.0
	if (b <= -2.15e+130)
		tmp = Float64(Float64(-b) / a);
	elseif (b <= 3.1e-8)
		tmp = Float64(Float64(sqrt(Float64(Float64(b * b) - Float64(Float64(a * 4.0) * c))) - 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 <= -2.15e+130)
		tmp = -b / a;
	elseif (b <= 3.1e-8)
		tmp = (sqrt(((b * b) - ((a * 4.0) * c))) - b) / (a * 2.0);
	else
		tmp = -c / b;
	end
	tmp_2 = tmp;
end
code[a_, b_, c_] := If[LessEqual[b, -2.15e+130], N[((-b) / a), $MachinePrecision], If[LessEqual[b, 3.1e-8], N[(N[(N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(a * 4.0), $MachinePrecision] * c), $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 -2.15 \cdot 10^{+130}:\\
\;\;\;\;\frac{-b}{a}\\

\mathbf{elif}\;b \leq 3.1 \cdot 10^{-8}:\\
\;\;\;\;\frac{\sqrt{b \cdot b - \left(a \cdot 4\right) \cdot c} - b}{a \cdot 2}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if b < -2.14999999999999992e130

    1. Initial program 53.4%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Step-by-step derivation
      1. *-commutative53.4%

        \[\leadsto \frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{\color{blue}{a \cdot 2}} \]
    3. Simplified53.4%

      \[\leadsto \color{blue}{\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{a \cdot 2}} \]
    4. Taylor expanded in b around -inf 97.0%

      \[\leadsto \color{blue}{-1 \cdot \frac{b}{a}} \]
    5. Step-by-step derivation
      1. associate-*r/97.0%

        \[\leadsto \color{blue}{\frac{-1 \cdot b}{a}} \]
      2. mul-1-neg97.0%

        \[\leadsto \frac{\color{blue}{-b}}{a} \]
    6. Simplified97.0%

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

    if -2.14999999999999992e130 < b < 3.1e-8

    1. Initial program 78.8%

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

    if 3.1e-8 < b

    1. Initial program 12.6%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Step-by-step derivation
      1. *-commutative12.6%

        \[\leadsto \frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{\color{blue}{a \cdot 2}} \]
    3. Simplified12.6%

      \[\leadsto \color{blue}{\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{a \cdot 2}} \]
    4. Taylor expanded in b around inf 87.6%

      \[\leadsto \color{blue}{-1 \cdot \frac{c}{b}} \]
    5. Step-by-step derivation
      1. mul-1-neg87.6%

        \[\leadsto \color{blue}{-\frac{c}{b}} \]
      2. distribute-neg-frac87.6%

        \[\leadsto \color{blue}{\frac{-c}{b}} \]
    6. Simplified87.6%

      \[\leadsto \color{blue}{\frac{-c}{b}} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification85.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b \leq -2.15 \cdot 10^{+130}:\\ \;\;\;\;\frac{-b}{a}\\ \mathbf{elif}\;b \leq 3.1 \cdot 10^{-8}:\\ \;\;\;\;\frac{\sqrt{b \cdot b - \left(a \cdot 4\right) \cdot c} - b}{a \cdot 2}\\ \mathbf{else}:\\ \;\;\;\;\frac{-c}{b}\\ \end{array} \]

Alternative 2: 79.7% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq -1.95 \cdot 10^{-91}:\\ \;\;\;\;\frac{c}{b} - \frac{b}{a}\\ \mathbf{elif}\;b \leq 3 \cdot 10^{-8}:\\ \;\;\;\;\frac{0.5}{a} \cdot \left(b + \sqrt{a \cdot \left(c \cdot -4\right)}\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{-c}{b}\\ \end{array} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (if (<= b -1.95e-91)
   (- (/ c b) (/ b a))
   (if (<= b 3e-8) (* (/ 0.5 a) (+ b (sqrt (* a (* c -4.0))))) (/ (- c) b))))
double code(double a, double b, double c) {
	double tmp;
	if (b <= -1.95e-91) {
		tmp = (c / b) - (b / a);
	} else if (b <= 3e-8) {
		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 <= (-1.95d-91)) then
        tmp = (c / b) - (b / a)
    else if (b <= 3d-8) 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 <= -1.95e-91) {
		tmp = (c / b) - (b / a);
	} else if (b <= 3e-8) {
		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 <= -1.95e-91:
		tmp = (c / b) - (b / a)
	elif b <= 3e-8:
		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 <= -1.95e-91)
		tmp = Float64(Float64(c / b) - Float64(b / a));
	elseif (b <= 3e-8)
		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 <= -1.95e-91)
		tmp = (c / b) - (b / a);
	elseif (b <= 3e-8)
		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, -1.95e-91], N[(N[(c / b), $MachinePrecision] - N[(b / a), $MachinePrecision]), $MachinePrecision], If[LessEqual[b, 3e-8], 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 -1.95 \cdot 10^{-91}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\

\mathbf{elif}\;b \leq 3 \cdot 10^{-8}:\\
\;\;\;\;\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 < -1.94999999999999997e-91

    1. Initial program 67.7%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Step-by-step derivation
      1. *-commutative67.7%

        \[\leadsto \frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{\color{blue}{a \cdot 2}} \]
    3. Simplified67.7%

      \[\leadsto \color{blue}{\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{a \cdot 2}} \]
    4. Taylor expanded in b around -inf 90.2%

      \[\leadsto \color{blue}{-1 \cdot \frac{b}{a} + \frac{c}{b}} \]
    5. Step-by-step derivation
      1. +-commutative90.2%

        \[\leadsto \color{blue}{\frac{c}{b} + -1 \cdot \frac{b}{a}} \]
      2. mul-1-neg90.2%

        \[\leadsto \frac{c}{b} + \color{blue}{\left(-\frac{b}{a}\right)} \]
      3. unsub-neg90.2%

        \[\leadsto \color{blue}{\frac{c}{b} - \frac{b}{a}} \]
    6. Simplified90.2%

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

    if -1.94999999999999997e-91 < b < 2.99999999999999973e-8

    1. Initial program 73.8%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Step-by-step derivation
      1. *-commutative73.8%

        \[\leadsto \frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{\color{blue}{a \cdot 2}} \]
    3. Simplified73.8%

      \[\leadsto \color{blue}{\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{a \cdot 2}} \]
    4. Applied egg-rr70.4%

      \[\leadsto \color{blue}{\frac{0.5}{a} \cdot \left(b + \sqrt{\mathsf{fma}\left(a, c \cdot -4, {b}^{2}\right)}\right)} \]
    5. Taylor expanded in a around inf 70.4%

      \[\leadsto \frac{0.5}{a} \cdot \left(b + \sqrt{\color{blue}{-4 \cdot \left(a \cdot c\right)}}\right) \]
    6. Step-by-step derivation
      1. *-commutative70.4%

        \[\leadsto \frac{0.5}{a} \cdot \left(b + \sqrt{\color{blue}{\left(a \cdot c\right) \cdot -4}}\right) \]
      2. associate-*r*70.4%

        \[\leadsto \frac{0.5}{a} \cdot \left(b + \sqrt{\color{blue}{a \cdot \left(c \cdot -4\right)}}\right) \]
    7. Simplified70.4%

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

    if 2.99999999999999973e-8 < b

    1. Initial program 12.6%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Step-by-step derivation
      1. *-commutative12.6%

        \[\leadsto \frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{\color{blue}{a \cdot 2}} \]
    3. Simplified12.6%

      \[\leadsto \color{blue}{\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{a \cdot 2}} \]
    4. Taylor expanded in b around inf 87.6%

      \[\leadsto \color{blue}{-1 \cdot \frac{c}{b}} \]
    5. Step-by-step derivation
      1. mul-1-neg87.6%

        \[\leadsto \color{blue}{-\frac{c}{b}} \]
      2. distribute-neg-frac87.6%

        \[\leadsto \color{blue}{\frac{-c}{b}} \]
    6. Simplified87.6%

      \[\leadsto \color{blue}{\frac{-c}{b}} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification83.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b \leq -1.95 \cdot 10^{-91}:\\ \;\;\;\;\frac{c}{b} - \frac{b}{a}\\ \mathbf{elif}\;b \leq 3 \cdot 10^{-8}:\\ \;\;\;\;\frac{0.5}{a} \cdot \left(b + \sqrt{a \cdot \left(c \cdot -4\right)}\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{-c}{b}\\ \end{array} \]

Alternative 3: 80.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq -2.2 \cdot 10^{-92}:\\ \;\;\;\;\frac{c}{b} - \frac{b}{a}\\ \mathbf{elif}\;b \leq 9.4 \cdot 10^{-8}:\\ \;\;\;\;\frac{\sqrt{a \cdot \left(c \cdot -4\right)} - b}{a \cdot 2}\\ \mathbf{else}:\\ \;\;\;\;\frac{-c}{b}\\ \end{array} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (if (<= b -2.2e-92)
   (- (/ c b) (/ b a))
   (if (<= b 9.4e-8) (/ (- (sqrt (* a (* c -4.0))) b) (* a 2.0)) (/ (- c) b))))
double code(double a, double b, double c) {
	double tmp;
	if (b <= -2.2e-92) {
		tmp = (c / b) - (b / a);
	} else if (b <= 9.4e-8) {
		tmp = (sqrt((a * (c * -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 <= (-2.2d-92)) then
        tmp = (c / b) - (b / a)
    else if (b <= 9.4d-8) then
        tmp = (sqrt((a * (c * (-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 <= -2.2e-92) {
		tmp = (c / b) - (b / a);
	} else if (b <= 9.4e-8) {
		tmp = (Math.sqrt((a * (c * -4.0))) - b) / (a * 2.0);
	} else {
		tmp = -c / b;
	}
	return tmp;
}
def code(a, b, c):
	tmp = 0
	if b <= -2.2e-92:
		tmp = (c / b) - (b / a)
	elif b <= 9.4e-8:
		tmp = (math.sqrt((a * (c * -4.0))) - b) / (a * 2.0)
	else:
		tmp = -c / b
	return tmp
function code(a, b, c)
	tmp = 0.0
	if (b <= -2.2e-92)
		tmp = Float64(Float64(c / b) - Float64(b / a));
	elseif (b <= 9.4e-8)
		tmp = Float64(Float64(sqrt(Float64(a * Float64(c * -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 <= -2.2e-92)
		tmp = (c / b) - (b / a);
	elseif (b <= 9.4e-8)
		tmp = (sqrt((a * (c * -4.0))) - b) / (a * 2.0);
	else
		tmp = -c / b;
	end
	tmp_2 = tmp;
end
code[a_, b_, c_] := If[LessEqual[b, -2.2e-92], N[(N[(c / b), $MachinePrecision] - N[(b / a), $MachinePrecision]), $MachinePrecision], If[LessEqual[b, 9.4e-8], N[(N[(N[Sqrt[N[(a * N[(c * -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 -2.2 \cdot 10^{-92}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\

\mathbf{elif}\;b \leq 9.4 \cdot 10^{-8}:\\
\;\;\;\;\frac{\sqrt{a \cdot \left(c \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 < -2.19999999999999987e-92

    1. Initial program 67.7%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Step-by-step derivation
      1. *-commutative67.7%

        \[\leadsto \frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{\color{blue}{a \cdot 2}} \]
    3. Simplified67.7%

      \[\leadsto \color{blue}{\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{a \cdot 2}} \]
    4. Taylor expanded in b around -inf 90.2%

      \[\leadsto \color{blue}{-1 \cdot \frac{b}{a} + \frac{c}{b}} \]
    5. Step-by-step derivation
      1. +-commutative90.2%

        \[\leadsto \color{blue}{\frac{c}{b} + -1 \cdot \frac{b}{a}} \]
      2. mul-1-neg90.2%

        \[\leadsto \frac{c}{b} + \color{blue}{\left(-\frac{b}{a}\right)} \]
      3. unsub-neg90.2%

        \[\leadsto \color{blue}{\frac{c}{b} - \frac{b}{a}} \]
    6. Simplified90.2%

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

    if -2.19999999999999987e-92 < b < 9.3999999999999995e-8

    1. Initial program 73.8%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Step-by-step derivation
      1. *-commutative73.8%

        \[\leadsto \frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{\color{blue}{a \cdot 2}} \]
    3. Simplified73.8%

      \[\leadsto \color{blue}{\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{a \cdot 2}} \]
    4. Taylor expanded in b around 0 71.2%

      \[\leadsto \frac{\left(-b\right) + \sqrt{\color{blue}{-4 \cdot \left(a \cdot c\right)}}}{a \cdot 2} \]
    5. Step-by-step derivation
      1. *-commutative71.2%

        \[\leadsto \frac{\left(-b\right) + \sqrt{\color{blue}{\left(a \cdot c\right) \cdot -4}}}{a \cdot 2} \]
      2. associate-*r*71.2%

        \[\leadsto \frac{\left(-b\right) + \sqrt{\color{blue}{a \cdot \left(c \cdot -4\right)}}}{a \cdot 2} \]
    6. Simplified71.2%

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

    if 9.3999999999999995e-8 < b

    1. Initial program 12.6%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Step-by-step derivation
      1. *-commutative12.6%

        \[\leadsto \frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{\color{blue}{a \cdot 2}} \]
    3. Simplified12.6%

      \[\leadsto \color{blue}{\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{a \cdot 2}} \]
    4. Taylor expanded in b around inf 87.6%

      \[\leadsto \color{blue}{-1 \cdot \frac{c}{b}} \]
    5. Step-by-step derivation
      1. mul-1-neg87.6%

        \[\leadsto \color{blue}{-\frac{c}{b}} \]
      2. distribute-neg-frac87.6%

        \[\leadsto \color{blue}{\frac{-c}{b}} \]
    6. Simplified87.6%

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

    \[\leadsto \begin{array}{l} \mathbf{if}\;b \leq -2.2 \cdot 10^{-92}:\\ \;\;\;\;\frac{c}{b} - \frac{b}{a}\\ \mathbf{elif}\;b \leq 9.4 \cdot 10^{-8}:\\ \;\;\;\;\frac{\sqrt{a \cdot \left(c \cdot -4\right)} - b}{a \cdot 2}\\ \mathbf{else}:\\ \;\;\;\;\frac{-c}{b}\\ \end{array} \]

Alternative 4: 68.2% accurate, 12.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq -4 \cdot 10^{-310}:\\ \;\;\;\;\frac{c}{b} - \frac{b}{a}\\ \mathbf{else}:\\ \;\;\;\;\frac{-c}{b}\\ \end{array} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (if (<= b -4e-310) (- (/ c b) (/ b a)) (/ (- c) b)))
double code(double a, double b, double c) {
	double tmp;
	if (b <= -4e-310) {
		tmp = (c / b) - (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 <= (-4d-310)) then
        tmp = (c / b) - (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 <= -4e-310) {
		tmp = (c / b) - (b / a);
	} else {
		tmp = -c / b;
	}
	return tmp;
}
def code(a, b, c):
	tmp = 0
	if b <= -4e-310:
		tmp = (c / b) - (b / a)
	else:
		tmp = -c / b
	return tmp
function code(a, b, c)
	tmp = 0.0
	if (b <= -4e-310)
		tmp = Float64(Float64(c / b) - Float64(b / a));
	else
		tmp = Float64(Float64(-c) / b);
	end
	return tmp
end
function tmp_2 = code(a, b, c)
	tmp = 0.0;
	if (b <= -4e-310)
		tmp = (c / b) - (b / a);
	else
		tmp = -c / b;
	end
	tmp_2 = tmp;
end
code[a_, b_, c_] := If[LessEqual[b, -4e-310], N[(N[(c / b), $MachinePrecision] - N[(b / a), $MachinePrecision]), $MachinePrecision], N[((-c) / b), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b \leq -4 \cdot 10^{-310}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if b < -3.999999999999988e-310

    1. Initial program 72.2%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Step-by-step derivation
      1. *-commutative72.2%

        \[\leadsto \frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{\color{blue}{a \cdot 2}} \]
    3. Simplified72.2%

      \[\leadsto \color{blue}{\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{a \cdot 2}} \]
    4. Taylor expanded in b around -inf 72.2%

      \[\leadsto \color{blue}{-1 \cdot \frac{b}{a} + \frac{c}{b}} \]
    5. Step-by-step derivation
      1. +-commutative72.2%

        \[\leadsto \color{blue}{\frac{c}{b} + -1 \cdot \frac{b}{a}} \]
      2. mul-1-neg72.2%

        \[\leadsto \frac{c}{b} + \color{blue}{\left(-\frac{b}{a}\right)} \]
      3. unsub-neg72.2%

        \[\leadsto \color{blue}{\frac{c}{b} - \frac{b}{a}} \]
    6. Simplified72.2%

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

    if -3.999999999999988e-310 < b

    1. Initial program 36.3%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Step-by-step derivation
      1. *-commutative36.3%

        \[\leadsto \frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{\color{blue}{a \cdot 2}} \]
    3. Simplified36.3%

      \[\leadsto \color{blue}{\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{a \cdot 2}} \]
    4. Taylor expanded in b around inf 60.1%

      \[\leadsto \color{blue}{-1 \cdot \frac{c}{b}} \]
    5. Step-by-step derivation
      1. mul-1-neg60.1%

        \[\leadsto \color{blue}{-\frac{c}{b}} \]
      2. distribute-neg-frac60.1%

        \[\leadsto \color{blue}{\frac{-c}{b}} \]
    6. Simplified60.1%

      \[\leadsto \color{blue}{\frac{-c}{b}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification66.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b \leq -4 \cdot 10^{-310}:\\ \;\;\;\;\frac{c}{b} - \frac{b}{a}\\ \mathbf{else}:\\ \;\;\;\;\frac{-c}{b}\\ \end{array} \]

Alternative 5: 43.6% accurate, 19.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq 6.2 \cdot 10^{+68}:\\ \;\;\;\;\frac{-b}{a}\\ \mathbf{else}:\\ \;\;\;\;\frac{c}{b}\\ \end{array} \end{array} \]
(FPCore (a b c) :precision binary64 (if (<= b 6.2e+68) (/ (- b) a) (/ c b)))
double code(double a, double b, double c) {
	double tmp;
	if (b <= 6.2e+68) {
		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 <= 6.2d+68) 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 <= 6.2e+68) {
		tmp = -b / a;
	} else {
		tmp = c / b;
	}
	return tmp;
}
def code(a, b, c):
	tmp = 0
	if b <= 6.2e+68:
		tmp = -b / a
	else:
		tmp = c / b
	return tmp
function code(a, b, c)
	tmp = 0.0
	if (b <= 6.2e+68)
		tmp = Float64(Float64(-b) / a);
	else
		tmp = Float64(c / b);
	end
	return tmp
end
function tmp_2 = code(a, b, c)
	tmp = 0.0;
	if (b <= 6.2e+68)
		tmp = -b / a;
	else
		tmp = c / b;
	end
	tmp_2 = tmp;
end
code[a_, b_, c_] := If[LessEqual[b, 6.2e+68], N[((-b) / a), $MachinePrecision], N[(c / b), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b \leq 6.2 \cdot 10^{+68}:\\
\;\;\;\;\frac{-b}{a}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if b < 6.1999999999999997e68

    1. Initial program 64.8%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Step-by-step derivation
      1. *-commutative64.8%

        \[\leadsto \frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{\color{blue}{a \cdot 2}} \]
    3. Simplified64.8%

      \[\leadsto \color{blue}{\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{a \cdot 2}} \]
    4. Taylor expanded in b around -inf 48.4%

      \[\leadsto \color{blue}{-1 \cdot \frac{b}{a}} \]
    5. Step-by-step derivation
      1. associate-*r/48.4%

        \[\leadsto \color{blue}{\frac{-1 \cdot b}{a}} \]
      2. mul-1-neg48.4%

        \[\leadsto \frac{\color{blue}{-b}}{a} \]
    6. Simplified48.4%

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

    if 6.1999999999999997e68 < b

    1. Initial program 14.1%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Step-by-step derivation
      1. *-commutative14.1%

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

      \[\leadsto \color{blue}{\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{a \cdot 2}} \]
    4. Applied egg-rr4.3%

      \[\leadsto \color{blue}{\frac{0.5}{a} \cdot \left(b + \sqrt{\mathsf{fma}\left(a, c \cdot -4, {b}^{2}\right)}\right)} \]
    5. Taylor expanded in b around -inf 38.6%

      \[\leadsto \color{blue}{\frac{c}{b}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification46.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b \leq 6.2 \cdot 10^{+68}:\\ \;\;\;\;\frac{-b}{a}\\ \mathbf{else}:\\ \;\;\;\;\frac{c}{b}\\ \end{array} \]

Alternative 6: 68.1% accurate, 19.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq 8.2 \cdot 10^{-306}:\\ \;\;\;\;\frac{-b}{a}\\ \mathbf{else}:\\ \;\;\;\;\frac{-c}{b}\\ \end{array} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (if (<= b 8.2e-306) (/ (- b) a) (/ (- c) b)))
double code(double a, double b, double c) {
	double tmp;
	if (b <= 8.2e-306) {
		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 <= 8.2d-306) 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 <= 8.2e-306) {
		tmp = -b / a;
	} else {
		tmp = -c / b;
	}
	return tmp;
}
def code(a, b, c):
	tmp = 0
	if b <= 8.2e-306:
		tmp = -b / a
	else:
		tmp = -c / b
	return tmp
function code(a, b, c)
	tmp = 0.0
	if (b <= 8.2e-306)
		tmp = Float64(Float64(-b) / a);
	else
		tmp = Float64(Float64(-c) / b);
	end
	return tmp
end
function tmp_2 = code(a, b, c)
	tmp = 0.0;
	if (b <= 8.2e-306)
		tmp = -b / a;
	else
		tmp = -c / b;
	end
	tmp_2 = tmp;
end
code[a_, b_, c_] := If[LessEqual[b, 8.2e-306], N[((-b) / a), $MachinePrecision], N[((-c) / b), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b \leq 8.2 \cdot 10^{-306}:\\
\;\;\;\;\frac{-b}{a}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if b < 8.19999999999999969e-306

    1. Initial program 72.2%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Step-by-step derivation
      1. *-commutative72.2%

        \[\leadsto \frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{\color{blue}{a \cdot 2}} \]
    3. Simplified72.2%

      \[\leadsto \color{blue}{\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{a \cdot 2}} \]
    4. Taylor expanded in b around -inf 72.2%

      \[\leadsto \color{blue}{-1 \cdot \frac{b}{a}} \]
    5. Step-by-step derivation
      1. associate-*r/72.2%

        \[\leadsto \color{blue}{\frac{-1 \cdot b}{a}} \]
      2. mul-1-neg72.2%

        \[\leadsto \frac{\color{blue}{-b}}{a} \]
    6. Simplified72.2%

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

    if 8.19999999999999969e-306 < b

    1. Initial program 36.3%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Step-by-step derivation
      1. *-commutative36.3%

        \[\leadsto \frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{\color{blue}{a \cdot 2}} \]
    3. Simplified36.3%

      \[\leadsto \color{blue}{\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{a \cdot 2}} \]
    4. Taylor expanded in b around inf 60.1%

      \[\leadsto \color{blue}{-1 \cdot \frac{c}{b}} \]
    5. Step-by-step derivation
      1. mul-1-neg60.1%

        \[\leadsto \color{blue}{-\frac{c}{b}} \]
      2. distribute-neg-frac60.1%

        \[\leadsto \color{blue}{\frac{-c}{b}} \]
    6. Simplified60.1%

      \[\leadsto \color{blue}{\frac{-c}{b}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification66.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b \leq 8.2 \cdot 10^{-306}:\\ \;\;\;\;\frac{-b}{a}\\ \mathbf{else}:\\ \;\;\;\;\frac{-c}{b}\\ \end{array} \]

Alternative 7: 2.5% accurate, 38.7× 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 55.5%

    \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
  2. Step-by-step derivation
    1. *-commutative55.5%

      \[\leadsto \frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{\color{blue}{a \cdot 2}} \]
  3. Simplified55.5%

    \[\leadsto \color{blue}{\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{a \cdot 2}} \]
  4. Applied egg-rr35.4%

    \[\leadsto \color{blue}{\frac{0.5}{a} \cdot \left(b + \sqrt{\mathsf{fma}\left(a, c \cdot -4, {b}^{2}\right)}\right)} \]
  5. Taylor expanded in a around 0 2.5%

    \[\leadsto \color{blue}{\frac{b}{a}} \]
  6. Final simplification2.5%

    \[\leadsto \frac{b}{a} \]

Alternative 8: 10.5% accurate, 38.7× 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 55.5%

    \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
  2. Step-by-step derivation
    1. *-commutative55.5%

      \[\leadsto \frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{\color{blue}{a \cdot 2}} \]
  3. Simplified55.5%

    \[\leadsto \color{blue}{\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{a \cdot 2}} \]
  4. Applied egg-rr35.4%

    \[\leadsto \color{blue}{\frac{0.5}{a} \cdot \left(b + \sqrt{\mathsf{fma}\left(a, c \cdot -4, {b}^{2}\right)}\right)} \]
  5. Taylor expanded in b around -inf 9.3%

    \[\leadsto \color{blue}{\frac{c}{b}} \]
  6. Final simplification9.3%

    \[\leadsto \frac{c}{b} \]

Reproduce

?
herbie shell --seed 2023331 
(FPCore (a b c)
  :name "Quadratic roots, full range"
  :precision binary64
  (/ (+ (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))) (* 2.0 a)))