quadm (p42, negative)

Percentage Accurate: 51.4% → 85.3%
Time: 12.1s
Alternatives: 7
Speedup: 19.1×

Specification

?
\[\begin{array}{l} \\ \frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a} \end{array} \]
(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(4.0 * Float64(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[(4.0 * N[(a * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{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 7 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: 51.4% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a} \end{array} \]
(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(4.0 * Float64(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[(4.0 * N[(a * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

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

Alternative 1: 85.3% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq -6.4 \cdot 10^{-55}:\\ \;\;\;\;\frac{-c}{b}\\ \mathbf{elif}\;b \leq 3.4 \cdot 10^{+76}:\\ \;\;\;\;-0.5 \cdot \frac{b + \sqrt{b \cdot b - a \cdot \left(c \cdot 4\right)}}{a}\\ \mathbf{else}:\\ \;\;\;\;\frac{-b}{a}\\ \end{array} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (if (<= b -6.4e-55)
   (/ (- c) b)
   (if (<= b 3.4e+76)
     (* -0.5 (/ (+ b (sqrt (- (* b b) (* a (* c 4.0))))) a))
     (/ (- b) a))))
double code(double a, double b, double c) {
	double tmp;
	if (b <= -6.4e-55) {
		tmp = -c / b;
	} else if (b <= 3.4e+76) {
		tmp = -0.5 * ((b + sqrt(((b * b) - (a * (c * 4.0))))) / a);
	} else {
		tmp = -b / a;
	}
	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 <= (-6.4d-55)) then
        tmp = -c / b
    else if (b <= 3.4d+76) then
        tmp = (-0.5d0) * ((b + sqrt(((b * b) - (a * (c * 4.0d0))))) / a)
    else
        tmp = -b / a
    end if
    code = tmp
end function
public static double code(double a, double b, double c) {
	double tmp;
	if (b <= -6.4e-55) {
		tmp = -c / b;
	} else if (b <= 3.4e+76) {
		tmp = -0.5 * ((b + Math.sqrt(((b * b) - (a * (c * 4.0))))) / a);
	} else {
		tmp = -b / a;
	}
	return tmp;
}
def code(a, b, c):
	tmp = 0
	if b <= -6.4e-55:
		tmp = -c / b
	elif b <= 3.4e+76:
		tmp = -0.5 * ((b + math.sqrt(((b * b) - (a * (c * 4.0))))) / a)
	else:
		tmp = -b / a
	return tmp
function code(a, b, c)
	tmp = 0.0
	if (b <= -6.4e-55)
		tmp = Float64(Float64(-c) / b);
	elseif (b <= 3.4e+76)
		tmp = Float64(-0.5 * Float64(Float64(b + sqrt(Float64(Float64(b * b) - Float64(a * Float64(c * 4.0))))) / a));
	else
		tmp = Float64(Float64(-b) / a);
	end
	return tmp
end
function tmp_2 = code(a, b, c)
	tmp = 0.0;
	if (b <= -6.4e-55)
		tmp = -c / b;
	elseif (b <= 3.4e+76)
		tmp = -0.5 * ((b + sqrt(((b * b) - (a * (c * 4.0))))) / a);
	else
		tmp = -b / a;
	end
	tmp_2 = tmp;
end
code[a_, b_, c_] := If[LessEqual[b, -6.4e-55], N[((-c) / b), $MachinePrecision], If[LessEqual[b, 3.4e+76], N[(-0.5 * N[(N[(b + N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(a * N[(c * 4.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision], N[((-b) / a), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b \leq -6.4 \cdot 10^{-55}:\\
\;\;\;\;\frac{-c}{b}\\

\mathbf{elif}\;b \leq 3.4 \cdot 10^{+76}:\\
\;\;\;\;-0.5 \cdot \frac{b + \sqrt{b \cdot b - a \cdot \left(c \cdot 4\right)}}{a}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if b < -6.4000000000000003e-55

    1. Initial program 15.7%

      \[\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a} \]
    2. Taylor expanded in b around -inf 92.0%

      \[\leadsto \color{blue}{-1 \cdot \frac{c}{b}} \]
    3. Step-by-step derivation
      1. associate-*r/92.0%

        \[\leadsto \color{blue}{\frac{-1 \cdot c}{b}} \]
      2. neg-mul-192.0%

        \[\leadsto \frac{\color{blue}{-c}}{b} \]
    4. Simplified92.0%

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

    if -6.4000000000000003e-55 < b < 3.3999999999999997e76

    1. Initial program 74.4%

      \[\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a} \]
    2. Simplified74.4%

      \[\leadsto \color{blue}{-0.5 \cdot \frac{b + \sqrt{\mathsf{fma}\left(a, c \cdot -4, b \cdot b\right)}}{a}} \]
    3. Step-by-step derivation
      1. fma-udef74.4%

        \[\leadsto -0.5 \cdot \frac{b + \sqrt{\color{blue}{a \cdot \left(c \cdot -4\right) + b \cdot b}}}{a} \]
      2. associate-*r*74.4%

        \[\leadsto -0.5 \cdot \frac{b + \sqrt{\color{blue}{\left(a \cdot c\right) \cdot -4} + b \cdot b}}{a} \]
      3. metadata-eval74.4%

        \[\leadsto -0.5 \cdot \frac{b + \sqrt{\left(a \cdot c\right) \cdot \color{blue}{\left(-4\right)} + b \cdot b}}{a} \]
      4. distribute-rgt-neg-in74.4%

        \[\leadsto -0.5 \cdot \frac{b + \sqrt{\color{blue}{\left(-\left(a \cdot c\right) \cdot 4\right)} + b \cdot b}}{a} \]
      5. *-commutative74.4%

        \[\leadsto -0.5 \cdot \frac{b + \sqrt{\left(-\color{blue}{4 \cdot \left(a \cdot c\right)}\right) + b \cdot b}}{a} \]
      6. +-commutative74.4%

        \[\leadsto -0.5 \cdot \frac{b + \sqrt{\color{blue}{b \cdot b + \left(-4 \cdot \left(a \cdot c\right)\right)}}}{a} \]
      7. sub-neg74.4%

        \[\leadsto -0.5 \cdot \frac{b + \sqrt{\color{blue}{b \cdot b - 4 \cdot \left(a \cdot c\right)}}}{a} \]
      8. *-commutative74.4%

        \[\leadsto -0.5 \cdot \frac{b + \sqrt{b \cdot b - \color{blue}{\left(a \cdot c\right) \cdot 4}}}{a} \]
      9. associate-*l*74.4%

        \[\leadsto -0.5 \cdot \frac{b + \sqrt{b \cdot b - \color{blue}{a \cdot \left(c \cdot 4\right)}}}{a} \]
    4. Applied egg-rr74.4%

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

    if 3.3999999999999997e76 < b

    1. Initial program 47.9%

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

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

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

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

      \[\leadsto \color{blue}{\frac{-b}{a}} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification85.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b \leq -6.4 \cdot 10^{-55}:\\ \;\;\;\;\frac{-c}{b}\\ \mathbf{elif}\;b \leq 3.4 \cdot 10^{+76}:\\ \;\;\;\;-0.5 \cdot \frac{b + \sqrt{b \cdot b - a \cdot \left(c \cdot 4\right)}}{a}\\ \mathbf{else}:\\ \;\;\;\;\frac{-b}{a}\\ \end{array} \]

Alternative 2: 80.8% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq -4.8 \cdot 10^{-54}:\\ \;\;\;\;\frac{-c}{b}\\ \mathbf{elif}\;b \leq 1.55 \cdot 10^{-72}:\\ \;\;\;\;-0.5 \cdot \frac{b + \sqrt{c \cdot \left(a \cdot -4\right)}}{a}\\ \mathbf{else}:\\ \;\;\;\;\frac{c}{b} - \frac{b}{a}\\ \end{array} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (if (<= b -4.8e-54)
   (/ (- c) b)
   (if (<= b 1.55e-72)
     (* -0.5 (/ (+ b (sqrt (* c (* a -4.0)))) a))
     (- (/ c b) (/ b a)))))
double code(double a, double b, double c) {
	double tmp;
	if (b <= -4.8e-54) {
		tmp = -c / b;
	} else if (b <= 1.55e-72) {
		tmp = -0.5 * ((b + sqrt((c * (a * -4.0)))) / a);
	} else {
		tmp = (c / b) - (b / a);
	}
	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 <= (-4.8d-54)) then
        tmp = -c / b
    else if (b <= 1.55d-72) then
        tmp = (-0.5d0) * ((b + sqrt((c * (a * (-4.0d0))))) / a)
    else
        tmp = (c / b) - (b / a)
    end if
    code = tmp
end function
public static double code(double a, double b, double c) {
	double tmp;
	if (b <= -4.8e-54) {
		tmp = -c / b;
	} else if (b <= 1.55e-72) {
		tmp = -0.5 * ((b + Math.sqrt((c * (a * -4.0)))) / a);
	} else {
		tmp = (c / b) - (b / a);
	}
	return tmp;
}
def code(a, b, c):
	tmp = 0
	if b <= -4.8e-54:
		tmp = -c / b
	elif b <= 1.55e-72:
		tmp = -0.5 * ((b + math.sqrt((c * (a * -4.0)))) / a)
	else:
		tmp = (c / b) - (b / a)
	return tmp
function code(a, b, c)
	tmp = 0.0
	if (b <= -4.8e-54)
		tmp = Float64(Float64(-c) / b);
	elseif (b <= 1.55e-72)
		tmp = Float64(-0.5 * Float64(Float64(b + sqrt(Float64(c * Float64(a * -4.0)))) / a));
	else
		tmp = Float64(Float64(c / b) - Float64(b / a));
	end
	return tmp
end
function tmp_2 = code(a, b, c)
	tmp = 0.0;
	if (b <= -4.8e-54)
		tmp = -c / b;
	elseif (b <= 1.55e-72)
		tmp = -0.5 * ((b + sqrt((c * (a * -4.0)))) / a);
	else
		tmp = (c / b) - (b / a);
	end
	tmp_2 = tmp;
end
code[a_, b_, c_] := If[LessEqual[b, -4.8e-54], N[((-c) / b), $MachinePrecision], If[LessEqual[b, 1.55e-72], N[(-0.5 * N[(N[(b + N[Sqrt[N[(c * N[(a * -4.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision], N[(N[(c / b), $MachinePrecision] - N[(b / a), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b \leq -4.8 \cdot 10^{-54}:\\
\;\;\;\;\frac{-c}{b}\\

\mathbf{elif}\;b \leq 1.55 \cdot 10^{-72}:\\
\;\;\;\;-0.5 \cdot \frac{b + \sqrt{c \cdot \left(a \cdot -4\right)}}{a}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if b < -4.80000000000000026e-54

    1. Initial program 15.7%

      \[\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a} \]
    2. Taylor expanded in b around -inf 92.0%

      \[\leadsto \color{blue}{-1 \cdot \frac{c}{b}} \]
    3. Step-by-step derivation
      1. associate-*r/92.0%

        \[\leadsto \color{blue}{\frac{-1 \cdot c}{b}} \]
      2. neg-mul-192.0%

        \[\leadsto \frac{\color{blue}{-c}}{b} \]
    4. Simplified92.0%

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

    if -4.80000000000000026e-54 < b < 1.5499999999999999e-72

    1. Initial program 69.6%

      \[\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a} \]
    2. Simplified69.6%

      \[\leadsto \color{blue}{-0.5 \cdot \frac{b + \sqrt{\mathsf{fma}\left(a, c \cdot -4, b \cdot b\right)}}{a}} \]
    3. Taylor expanded in a around inf 65.2%

      \[\leadsto -0.5 \cdot \frac{b + \sqrt{\color{blue}{-4 \cdot \left(c \cdot a\right)}}}{a} \]
    4. Step-by-step derivation
      1. *-commutative65.2%

        \[\leadsto -0.5 \cdot \frac{b + \sqrt{\color{blue}{\left(c \cdot a\right) \cdot -4}}}{a} \]
      2. associate-*r*65.3%

        \[\leadsto -0.5 \cdot \frac{b + \sqrt{\color{blue}{c \cdot \left(a \cdot -4\right)}}}{a} \]
    5. Simplified65.3%

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

    if 1.5499999999999999e-72 < b

    1. Initial program 61.5%

      \[\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a} \]
    2. Taylor expanded in b around inf 87.4%

      \[\leadsto \color{blue}{\frac{c}{b} + -1 \cdot \frac{b}{a}} \]
    3. Step-by-step derivation
      1. mul-1-neg87.4%

        \[\leadsto \frac{c}{b} + \color{blue}{\left(-\frac{b}{a}\right)} \]
      2. unsub-neg87.4%

        \[\leadsto \color{blue}{\frac{c}{b} - \frac{b}{a}} \]
    4. Simplified87.4%

      \[\leadsto \color{blue}{\frac{c}{b} - \frac{b}{a}} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification82.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b \leq -4.8 \cdot 10^{-54}:\\ \;\;\;\;\frac{-c}{b}\\ \mathbf{elif}\;b \leq 1.55 \cdot 10^{-72}:\\ \;\;\;\;-0.5 \cdot \frac{b + \sqrt{c \cdot \left(a \cdot -4\right)}}{a}\\ \mathbf{else}:\\ \;\;\;\;\frac{c}{b} - \frac{b}{a}\\ \end{array} \]

Alternative 3: 68.2% accurate, 12.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq -5 \cdot 10^{-310}:\\ \;\;\;\;\frac{-c}{b}\\ \mathbf{else}:\\ \;\;\;\;\frac{c}{b} - \frac{b}{a}\\ \end{array} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (if (<= b -5e-310) (/ (- c) b) (- (/ c b) (/ b a))))
double code(double a, double b, double c) {
	double tmp;
	if (b <= -5e-310) {
		tmp = -c / b;
	} else {
		tmp = (c / b) - (b / a);
	}
	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 <= (-5d-310)) then
        tmp = -c / b
    else
        tmp = (c / b) - (b / a)
    end if
    code = tmp
end function
public static double code(double a, double b, double c) {
	double tmp;
	if (b <= -5e-310) {
		tmp = -c / b;
	} else {
		tmp = (c / b) - (b / a);
	}
	return tmp;
}
def code(a, b, c):
	tmp = 0
	if b <= -5e-310:
		tmp = -c / b
	else:
		tmp = (c / b) - (b / a)
	return tmp
function code(a, b, c)
	tmp = 0.0
	if (b <= -5e-310)
		tmp = Float64(Float64(-c) / b);
	else
		tmp = Float64(Float64(c / b) - Float64(b / a));
	end
	return tmp
end
function tmp_2 = code(a, b, c)
	tmp = 0.0;
	if (b <= -5e-310)
		tmp = -c / b;
	else
		tmp = (c / b) - (b / a);
	end
	tmp_2 = tmp;
end
code[a_, b_, c_] := If[LessEqual[b, -5e-310], N[((-c) / b), $MachinePrecision], N[(N[(c / b), $MachinePrecision] - N[(b / a), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b \leq -5 \cdot 10^{-310}:\\
\;\;\;\;\frac{-c}{b}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if b < -4.999999999999985e-310

    1. Initial program 33.1%

      \[\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a} \]
    2. Taylor expanded in b around -inf 69.3%

      \[\leadsto \color{blue}{-1 \cdot \frac{c}{b}} \]
    3. Step-by-step derivation
      1. associate-*r/69.3%

        \[\leadsto \color{blue}{\frac{-1 \cdot c}{b}} \]
      2. neg-mul-169.3%

        \[\leadsto \frac{\color{blue}{-c}}{b} \]
    4. Simplified69.3%

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

    if -4.999999999999985e-310 < b

    1. Initial program 65.1%

      \[\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a} \]
    2. Taylor expanded in b around inf 71.9%

      \[\leadsto \color{blue}{\frac{c}{b} + -1 \cdot \frac{b}{a}} \]
    3. Step-by-step derivation
      1. mul-1-neg71.9%

        \[\leadsto \frac{c}{b} + \color{blue}{\left(-\frac{b}{a}\right)} \]
      2. unsub-neg71.9%

        \[\leadsto \color{blue}{\frac{c}{b} - \frac{b}{a}} \]
    4. Simplified71.9%

      \[\leadsto \color{blue}{\frac{c}{b} - \frac{b}{a}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification70.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b \leq -5 \cdot 10^{-310}:\\ \;\;\;\;\frac{-c}{b}\\ \mathbf{else}:\\ \;\;\;\;\frac{c}{b} - \frac{b}{a}\\ \end{array} \]

Alternative 4: 43.0% accurate, 19.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq -106000000000:\\ \;\;\;\;\frac{c}{b}\\ \mathbf{else}:\\ \;\;\;\;\frac{-b}{a}\\ \end{array} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (if (<= b -106000000000.0) (/ c b) (/ (- b) a)))
double code(double a, double b, double c) {
	double tmp;
	if (b <= -106000000000.0) {
		tmp = c / b;
	} else {
		tmp = -b / a;
	}
	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 <= (-106000000000.0d0)) then
        tmp = c / b
    else
        tmp = -b / a
    end if
    code = tmp
end function
public static double code(double a, double b, double c) {
	double tmp;
	if (b <= -106000000000.0) {
		tmp = c / b;
	} else {
		tmp = -b / a;
	}
	return tmp;
}
def code(a, b, c):
	tmp = 0
	if b <= -106000000000.0:
		tmp = c / b
	else:
		tmp = -b / a
	return tmp
function code(a, b, c)
	tmp = 0.0
	if (b <= -106000000000.0)
		tmp = Float64(c / b);
	else
		tmp = Float64(Float64(-b) / a);
	end
	return tmp
end
function tmp_2 = code(a, b, c)
	tmp = 0.0;
	if (b <= -106000000000.0)
		tmp = c / b;
	else
		tmp = -b / a;
	end
	tmp_2 = tmp;
end
code[a_, b_, c_] := If[LessEqual[b, -106000000000.0], N[(c / b), $MachinePrecision], N[((-b) / a), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b \leq -106000000000:\\
\;\;\;\;\frac{c}{b}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if b < -1.06e11

    1. Initial program 13.2%

      \[\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a} \]
    2. Step-by-step derivation
      1. clear-num13.1%

        \[\leadsto \color{blue}{\frac{1}{\frac{2 \cdot a}{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}}} \]
      2. inv-pow13.1%

        \[\leadsto \color{blue}{{\left(\frac{2 \cdot a}{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}\right)}^{-1}} \]
    3. Applied egg-rr3.7%

      \[\leadsto \color{blue}{{\left(\frac{a \cdot 2}{b - \sqrt{\mathsf{fma}\left(a, c \cdot -4, b \cdot b\right)}}\right)}^{-1}} \]
    4. Step-by-step derivation
      1. unpow-13.7%

        \[\leadsto \color{blue}{\frac{1}{\frac{a \cdot 2}{b - \sqrt{\mathsf{fma}\left(a, c \cdot -4, b \cdot b\right)}}}} \]
      2. fma-udef3.7%

        \[\leadsto \frac{1}{\frac{a \cdot 2}{b - \sqrt{\color{blue}{a \cdot \left(c \cdot -4\right) + b \cdot b}}}} \]
      3. *-commutative3.7%

        \[\leadsto \frac{1}{\frac{a \cdot 2}{b - \sqrt{a \cdot \color{blue}{\left(-4 \cdot c\right)} + b \cdot b}}} \]
      4. associate-*l*3.7%

        \[\leadsto \frac{1}{\frac{a \cdot 2}{b - \sqrt{\color{blue}{\left(a \cdot -4\right) \cdot c} + b \cdot b}}} \]
      5. *-commutative3.7%

        \[\leadsto \frac{1}{\frac{a \cdot 2}{b - \sqrt{\color{blue}{c \cdot \left(a \cdot -4\right)} + b \cdot b}}} \]
      6. fma-def3.7%

        \[\leadsto \frac{1}{\frac{a \cdot 2}{b - \sqrt{\color{blue}{\mathsf{fma}\left(c, a \cdot -4, b \cdot b\right)}}}} \]
    5. Simplified3.7%

      \[\leadsto \color{blue}{\frac{1}{\frac{a \cdot 2}{b - \sqrt{\mathsf{fma}\left(c, a \cdot -4, b \cdot b\right)}}}} \]
    6. Taylor expanded in a around 0 32.6%

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

    if -1.06e11 < b

    1. Initial program 63.8%

      \[\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a} \]
    2. Taylor expanded in b around inf 51.6%

      \[\leadsto \color{blue}{-1 \cdot \frac{b}{a}} \]
    3. Step-by-step derivation
      1. associate-*r/51.6%

        \[\leadsto \color{blue}{\frac{-1 \cdot b}{a}} \]
      2. mul-1-neg51.6%

        \[\leadsto \frac{\color{blue}{-b}}{a} \]
    4. Simplified51.6%

      \[\leadsto \color{blue}{\frac{-b}{a}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification46.1%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b \leq -106000000000:\\ \;\;\;\;\frac{c}{b}\\ \mathbf{else}:\\ \;\;\;\;\frac{-b}{a}\\ \end{array} \]

Alternative 5: 68.0% accurate, 19.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq -5.2 \cdot 10^{-295}:\\ \;\;\;\;\frac{-c}{b}\\ \mathbf{else}:\\ \;\;\;\;\frac{-b}{a}\\ \end{array} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (if (<= b -5.2e-295) (/ (- c) b) (/ (- b) a)))
double code(double a, double b, double c) {
	double tmp;
	if (b <= -5.2e-295) {
		tmp = -c / b;
	} else {
		tmp = -b / a;
	}
	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 <= (-5.2d-295)) then
        tmp = -c / b
    else
        tmp = -b / a
    end if
    code = tmp
end function
public static double code(double a, double b, double c) {
	double tmp;
	if (b <= -5.2e-295) {
		tmp = -c / b;
	} else {
		tmp = -b / a;
	}
	return tmp;
}
def code(a, b, c):
	tmp = 0
	if b <= -5.2e-295:
		tmp = -c / b
	else:
		tmp = -b / a
	return tmp
function code(a, b, c)
	tmp = 0.0
	if (b <= -5.2e-295)
		tmp = Float64(Float64(-c) / b);
	else
		tmp = Float64(Float64(-b) / a);
	end
	return tmp
end
function tmp_2 = code(a, b, c)
	tmp = 0.0;
	if (b <= -5.2e-295)
		tmp = -c / b;
	else
		tmp = -b / a;
	end
	tmp_2 = tmp;
end
code[a_, b_, c_] := If[LessEqual[b, -5.2e-295], N[((-c) / b), $MachinePrecision], N[((-b) / a), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b \leq -5.2 \cdot 10^{-295}:\\
\;\;\;\;\frac{-c}{b}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if b < -5.1999999999999997e-295

    1. Initial program 32.5%

      \[\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a} \]
    2. Taylor expanded in b around -inf 69.8%

      \[\leadsto \color{blue}{-1 \cdot \frac{c}{b}} \]
    3. Step-by-step derivation
      1. associate-*r/69.8%

        \[\leadsto \color{blue}{\frac{-1 \cdot c}{b}} \]
      2. neg-mul-169.8%

        \[\leadsto \frac{\color{blue}{-c}}{b} \]
    4. Simplified69.8%

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

    if -5.1999999999999997e-295 < b

    1. Initial program 65.3%

      \[\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a} \]
    2. Taylor expanded in b around inf 71.0%

      \[\leadsto \color{blue}{-1 \cdot \frac{b}{a}} \]
    3. Step-by-step derivation
      1. associate-*r/71.0%

        \[\leadsto \color{blue}{\frac{-1 \cdot b}{a}} \]
      2. mul-1-neg71.0%

        \[\leadsto \frac{\color{blue}{-b}}{a} \]
    4. Simplified71.0%

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

    \[\leadsto \begin{array}{l} \mathbf{if}\;b \leq -5.2 \cdot 10^{-295}:\\ \;\;\;\;\frac{-c}{b}\\ \mathbf{else}:\\ \;\;\;\;\frac{-b}{a}\\ \end{array} \]

Alternative 6: 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 49.2%

    \[\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a} \]
  2. Step-by-step derivation
    1. clear-num49.0%

      \[\leadsto \color{blue}{\frac{1}{\frac{2 \cdot a}{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}}} \]
    2. inv-pow49.0%

      \[\leadsto \color{blue}{{\left(\frac{2 \cdot a}{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}\right)}^{-1}} \]
  3. Applied egg-rr29.8%

    \[\leadsto \color{blue}{{\left(\frac{a \cdot 2}{b - \sqrt{\mathsf{fma}\left(a, c \cdot -4, b \cdot b\right)}}\right)}^{-1}} \]
  4. Step-by-step derivation
    1. unpow-129.8%

      \[\leadsto \color{blue}{\frac{1}{\frac{a \cdot 2}{b - \sqrt{\mathsf{fma}\left(a, c \cdot -4, b \cdot b\right)}}}} \]
    2. fma-udef29.8%

      \[\leadsto \frac{1}{\frac{a \cdot 2}{b - \sqrt{\color{blue}{a \cdot \left(c \cdot -4\right) + b \cdot b}}}} \]
    3. *-commutative29.8%

      \[\leadsto \frac{1}{\frac{a \cdot 2}{b - \sqrt{a \cdot \color{blue}{\left(-4 \cdot c\right)} + b \cdot b}}} \]
    4. associate-*l*29.8%

      \[\leadsto \frac{1}{\frac{a \cdot 2}{b - \sqrt{\color{blue}{\left(a \cdot -4\right) \cdot c} + b \cdot b}}} \]
    5. *-commutative29.8%

      \[\leadsto \frac{1}{\frac{a \cdot 2}{b - \sqrt{\color{blue}{c \cdot \left(a \cdot -4\right)} + b \cdot b}}} \]
    6. fma-def29.8%

      \[\leadsto \frac{1}{\frac{a \cdot 2}{b - \sqrt{\color{blue}{\mathsf{fma}\left(c, a \cdot -4, b \cdot b\right)}}}} \]
  5. Simplified29.8%

    \[\leadsto \color{blue}{\frac{1}{\frac{a \cdot 2}{b - \sqrt{\mathsf{fma}\left(c, a \cdot -4, b \cdot b\right)}}}} \]
  6. Taylor expanded in b around -inf 2.5%

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

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

Alternative 7: 11.1% 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 49.2%

    \[\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a} \]
  2. Step-by-step derivation
    1. clear-num49.0%

      \[\leadsto \color{blue}{\frac{1}{\frac{2 \cdot a}{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}}} \]
    2. inv-pow49.0%

      \[\leadsto \color{blue}{{\left(\frac{2 \cdot a}{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}\right)}^{-1}} \]
  3. Applied egg-rr29.8%

    \[\leadsto \color{blue}{{\left(\frac{a \cdot 2}{b - \sqrt{\mathsf{fma}\left(a, c \cdot -4, b \cdot b\right)}}\right)}^{-1}} \]
  4. Step-by-step derivation
    1. unpow-129.8%

      \[\leadsto \color{blue}{\frac{1}{\frac{a \cdot 2}{b - \sqrt{\mathsf{fma}\left(a, c \cdot -4, b \cdot b\right)}}}} \]
    2. fma-udef29.8%

      \[\leadsto \frac{1}{\frac{a \cdot 2}{b - \sqrt{\color{blue}{a \cdot \left(c \cdot -4\right) + b \cdot b}}}} \]
    3. *-commutative29.8%

      \[\leadsto \frac{1}{\frac{a \cdot 2}{b - \sqrt{a \cdot \color{blue}{\left(-4 \cdot c\right)} + b \cdot b}}} \]
    4. associate-*l*29.8%

      \[\leadsto \frac{1}{\frac{a \cdot 2}{b - \sqrt{\color{blue}{\left(a \cdot -4\right) \cdot c} + b \cdot b}}} \]
    5. *-commutative29.8%

      \[\leadsto \frac{1}{\frac{a \cdot 2}{b - \sqrt{\color{blue}{c \cdot \left(a \cdot -4\right)} + b \cdot b}}} \]
    6. fma-def29.8%

      \[\leadsto \frac{1}{\frac{a \cdot 2}{b - \sqrt{\color{blue}{\mathsf{fma}\left(c, a \cdot -4, b \cdot b\right)}}}} \]
  5. Simplified29.8%

    \[\leadsto \color{blue}{\frac{1}{\frac{a \cdot 2}{b - \sqrt{\mathsf{fma}\left(c, a \cdot -4, b \cdot b\right)}}}} \]
  6. Taylor expanded in a around 0 11.6%

    \[\leadsto \color{blue}{\frac{c}{b}} \]
  7. Final simplification11.6%

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

Developer target: 70.1% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}\\ \mathbf{if}\;b < 0:\\ \;\;\;\;\frac{c}{a \cdot \frac{\left(-b\right) + t_0}{2 \cdot a}}\\ \mathbf{else}:\\ \;\;\;\;\frac{\left(-b\right) - t_0}{2 \cdot a}\\ \end{array} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (let* ((t_0 (sqrt (- (* b b) (* 4.0 (* a c))))))
   (if (< b 0.0)
     (/ c (* a (/ (+ (- b) t_0) (* 2.0 a))))
     (/ (- (- b) t_0) (* 2.0 a)))))
double code(double a, double b, double c) {
	double t_0 = sqrt(((b * b) - (4.0 * (a * c))));
	double tmp;
	if (b < 0.0) {
		tmp = c / (a * ((-b + t_0) / (2.0 * a)));
	} else {
		tmp = (-b - t_0) / (2.0 * a);
	}
	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) :: t_0
    real(8) :: tmp
    t_0 = sqrt(((b * b) - (4.0d0 * (a * c))))
    if (b < 0.0d0) then
        tmp = c / (a * ((-b + t_0) / (2.0d0 * a)))
    else
        tmp = (-b - t_0) / (2.0d0 * a)
    end if
    code = tmp
end function
public static double code(double a, double b, double c) {
	double t_0 = Math.sqrt(((b * b) - (4.0 * (a * c))));
	double tmp;
	if (b < 0.0) {
		tmp = c / (a * ((-b + t_0) / (2.0 * a)));
	} else {
		tmp = (-b - t_0) / (2.0 * a);
	}
	return tmp;
}
def code(a, b, c):
	t_0 = math.sqrt(((b * b) - (4.0 * (a * c))))
	tmp = 0
	if b < 0.0:
		tmp = c / (a * ((-b + t_0) / (2.0 * a)))
	else:
		tmp = (-b - t_0) / (2.0 * a)
	return tmp
function code(a, b, c)
	t_0 = sqrt(Float64(Float64(b * b) - Float64(4.0 * Float64(a * c))))
	tmp = 0.0
	if (b < 0.0)
		tmp = Float64(c / Float64(a * Float64(Float64(Float64(-b) + t_0) / Float64(2.0 * a))));
	else
		tmp = Float64(Float64(Float64(-b) - t_0) / Float64(2.0 * a));
	end
	return tmp
end
function tmp_2 = code(a, b, c)
	t_0 = sqrt(((b * b) - (4.0 * (a * c))));
	tmp = 0.0;
	if (b < 0.0)
		tmp = c / (a * ((-b + t_0) / (2.0 * a)));
	else
		tmp = (-b - t_0) / (2.0 * a);
	end
	tmp_2 = tmp;
end
code[a_, b_, c_] := Block[{t$95$0 = N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(4.0 * N[(a * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]}, If[Less[b, 0.0], N[(c / N[(a * N[(N[((-b) + t$95$0), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[((-b) - t$95$0), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}\\
\mathbf{if}\;b < 0:\\
\;\;\;\;\frac{c}{a \cdot \frac{\left(-b\right) + t_0}{2 \cdot a}}\\

\mathbf{else}:\\
\;\;\;\;\frac{\left(-b\right) - t_0}{2 \cdot a}\\


\end{array}
\end{array}

Reproduce

?
herbie shell --seed 2023215 
(FPCore (a b c)
  :name "quadm (p42, negative)"
  :precision binary64

  :herbie-target
  (if (< b 0.0) (/ c (* a (/ (+ (- b) (sqrt (- (* b b) (* 4.0 (* a c))))) (* 2.0 a)))) (/ (- (- b) (sqrt (- (* b b) (* 4.0 (* a c))))) (* 2.0 a)))

  (/ (- (- b) (sqrt (- (* b b) (* 4.0 (* a c))))) (* 2.0 a)))