quad2m (problem 3.2.1, negative)

Percentage Accurate: 52.0% → 84.1%
Time: 11.3s
Alternatives: 7
Speedup: 11.2×

Specification

?
\[\begin{array}{l} \\ \frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{a} \end{array} \]
(FPCore (a b_2 c)
 :precision binary64
 (/ (- (- b_2) (sqrt (- (* b_2 b_2) (* a c)))) a))
double code(double a, double b_2, double c) {
	return (-b_2 - sqrt(((b_2 * b_2) - (a * c)))) / a;
}
real(8) function code(a, b_2, c)
    real(8), intent (in) :: a
    real(8), intent (in) :: b_2
    real(8), intent (in) :: c
    code = (-b_2 - sqrt(((b_2 * b_2) - (a * c)))) / a
end function
public static double code(double a, double b_2, double c) {
	return (-b_2 - Math.sqrt(((b_2 * b_2) - (a * c)))) / a;
}
def code(a, b_2, c):
	return (-b_2 - math.sqrt(((b_2 * b_2) - (a * c)))) / a
function code(a, b_2, c)
	return Float64(Float64(Float64(-b_2) - sqrt(Float64(Float64(b_2 * b_2) - Float64(a * c)))) / a)
end
function tmp = code(a, b_2, c)
	tmp = (-b_2 - sqrt(((b_2 * b_2) - (a * c)))) / a;
end
code[a_, b$95$2_, c_] := N[(N[((-b$95$2) - N[Sqrt[N[(N[(b$95$2 * b$95$2), $MachinePrecision] - N[(a * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / a), $MachinePrecision]
\begin{array}{l}

\\
\frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{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: 52.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{a} \end{array} \]
(FPCore (a b_2 c)
 :precision binary64
 (/ (- (- b_2) (sqrt (- (* b_2 b_2) (* a c)))) a))
double code(double a, double b_2, double c) {
	return (-b_2 - sqrt(((b_2 * b_2) - (a * c)))) / a;
}
real(8) function code(a, b_2, c)
    real(8), intent (in) :: a
    real(8), intent (in) :: b_2
    real(8), intent (in) :: c
    code = (-b_2 - sqrt(((b_2 * b_2) - (a * c)))) / a
end function
public static double code(double a, double b_2, double c) {
	return (-b_2 - Math.sqrt(((b_2 * b_2) - (a * c)))) / a;
}
def code(a, b_2, c):
	return (-b_2 - math.sqrt(((b_2 * b_2) - (a * c)))) / a
function code(a, b_2, c)
	return Float64(Float64(Float64(-b_2) - sqrt(Float64(Float64(b_2 * b_2) - Float64(a * c)))) / a)
end
function tmp = code(a, b_2, c)
	tmp = (-b_2 - sqrt(((b_2 * b_2) - (a * c)))) / a;
end
code[a_, b$95$2_, c_] := N[(N[((-b$95$2) - N[Sqrt[N[(N[(b$95$2 * b$95$2), $MachinePrecision] - N[(a * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / a), $MachinePrecision]
\begin{array}{l}

\\
\frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{a}
\end{array}

Alternative 1: 84.1% accurate, 0.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{-0.5 \cdot c}{b\_2}\\ t_1 := \frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - c \cdot a}}{a}\\ \mathbf{if}\;b\_2 \leq -1.2 \cdot 10^{-54}:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;b\_2 \leq -5 \cdot 10^{-109}:\\ \;\;\;\;t\_1\\ \mathbf{elif}\;b\_2 \leq -1.05 \cdot 10^{-178}:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;b\_2 \leq 2.4 \cdot 10^{+62}:\\ \;\;\;\;t\_1\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot \frac{b\_2}{a} + 0.5 \cdot \frac{c}{b\_2}\\ \end{array} \end{array} \]
(FPCore (a b_2 c)
 :precision binary64
 (let* ((t_0 (/ (* -0.5 c) b_2))
        (t_1 (/ (- (- b_2) (sqrt (- (* b_2 b_2) (* c a)))) a)))
   (if (<= b_2 -1.2e-54)
     t_0
     (if (<= b_2 -5e-109)
       t_1
       (if (<= b_2 -1.05e-178)
         t_0
         (if (<= b_2 2.4e+62)
           t_1
           (+ (* -2.0 (/ b_2 a)) (* 0.5 (/ c b_2)))))))))
double code(double a, double b_2, double c) {
	double t_0 = (-0.5 * c) / b_2;
	double t_1 = (-b_2 - sqrt(((b_2 * b_2) - (c * a)))) / a;
	double tmp;
	if (b_2 <= -1.2e-54) {
		tmp = t_0;
	} else if (b_2 <= -5e-109) {
		tmp = t_1;
	} else if (b_2 <= -1.05e-178) {
		tmp = t_0;
	} else if (b_2 <= 2.4e+62) {
		tmp = t_1;
	} else {
		tmp = (-2.0 * (b_2 / a)) + (0.5 * (c / b_2));
	}
	return tmp;
}
real(8) function code(a, b_2, c)
    real(8), intent (in) :: a
    real(8), intent (in) :: b_2
    real(8), intent (in) :: c
    real(8) :: t_0
    real(8) :: t_1
    real(8) :: tmp
    t_0 = ((-0.5d0) * c) / b_2
    t_1 = (-b_2 - sqrt(((b_2 * b_2) - (c * a)))) / a
    if (b_2 <= (-1.2d-54)) then
        tmp = t_0
    else if (b_2 <= (-5d-109)) then
        tmp = t_1
    else if (b_2 <= (-1.05d-178)) then
        tmp = t_0
    else if (b_2 <= 2.4d+62) then
        tmp = t_1
    else
        tmp = ((-2.0d0) * (b_2 / a)) + (0.5d0 * (c / b_2))
    end if
    code = tmp
end function
public static double code(double a, double b_2, double c) {
	double t_0 = (-0.5 * c) / b_2;
	double t_1 = (-b_2 - Math.sqrt(((b_2 * b_2) - (c * a)))) / a;
	double tmp;
	if (b_2 <= -1.2e-54) {
		tmp = t_0;
	} else if (b_2 <= -5e-109) {
		tmp = t_1;
	} else if (b_2 <= -1.05e-178) {
		tmp = t_0;
	} else if (b_2 <= 2.4e+62) {
		tmp = t_1;
	} else {
		tmp = (-2.0 * (b_2 / a)) + (0.5 * (c / b_2));
	}
	return tmp;
}
def code(a, b_2, c):
	t_0 = (-0.5 * c) / b_2
	t_1 = (-b_2 - math.sqrt(((b_2 * b_2) - (c * a)))) / a
	tmp = 0
	if b_2 <= -1.2e-54:
		tmp = t_0
	elif b_2 <= -5e-109:
		tmp = t_1
	elif b_2 <= -1.05e-178:
		tmp = t_0
	elif b_2 <= 2.4e+62:
		tmp = t_1
	else:
		tmp = (-2.0 * (b_2 / a)) + (0.5 * (c / b_2))
	return tmp
function code(a, b_2, c)
	t_0 = Float64(Float64(-0.5 * c) / b_2)
	t_1 = Float64(Float64(Float64(-b_2) - sqrt(Float64(Float64(b_2 * b_2) - Float64(c * a)))) / a)
	tmp = 0.0
	if (b_2 <= -1.2e-54)
		tmp = t_0;
	elseif (b_2 <= -5e-109)
		tmp = t_1;
	elseif (b_2 <= -1.05e-178)
		tmp = t_0;
	elseif (b_2 <= 2.4e+62)
		tmp = t_1;
	else
		tmp = Float64(Float64(-2.0 * Float64(b_2 / a)) + Float64(0.5 * Float64(c / b_2)));
	end
	return tmp
end
function tmp_2 = code(a, b_2, c)
	t_0 = (-0.5 * c) / b_2;
	t_1 = (-b_2 - sqrt(((b_2 * b_2) - (c * a)))) / a;
	tmp = 0.0;
	if (b_2 <= -1.2e-54)
		tmp = t_0;
	elseif (b_2 <= -5e-109)
		tmp = t_1;
	elseif (b_2 <= -1.05e-178)
		tmp = t_0;
	elseif (b_2 <= 2.4e+62)
		tmp = t_1;
	else
		tmp = (-2.0 * (b_2 / a)) + (0.5 * (c / b_2));
	end
	tmp_2 = tmp;
end
code[a_, b$95$2_, c_] := Block[{t$95$0 = N[(N[(-0.5 * c), $MachinePrecision] / b$95$2), $MachinePrecision]}, Block[{t$95$1 = N[(N[((-b$95$2) - N[Sqrt[N[(N[(b$95$2 * b$95$2), $MachinePrecision] - N[(c * a), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / a), $MachinePrecision]}, If[LessEqual[b$95$2, -1.2e-54], t$95$0, If[LessEqual[b$95$2, -5e-109], t$95$1, If[LessEqual[b$95$2, -1.05e-178], t$95$0, If[LessEqual[b$95$2, 2.4e+62], t$95$1, N[(N[(-2.0 * N[(b$95$2 / a), $MachinePrecision]), $MachinePrecision] + N[(0.5 * N[(c / b$95$2), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{-0.5 \cdot c}{b\_2}\\
t_1 := \frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - c \cdot a}}{a}\\
\mathbf{if}\;b\_2 \leq -1.2 \cdot 10^{-54}:\\
\;\;\;\;t\_0\\

\mathbf{elif}\;b\_2 \leq -5 \cdot 10^{-109}:\\
\;\;\;\;t\_1\\

\mathbf{elif}\;b\_2 \leq -1.05 \cdot 10^{-178}:\\
\;\;\;\;t\_0\\

\mathbf{elif}\;b\_2 \leq 2.4 \cdot 10^{+62}:\\
\;\;\;\;t\_1\\

\mathbf{else}:\\
\;\;\;\;-2 \cdot \frac{b\_2}{a} + 0.5 \cdot \frac{c}{b\_2}\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if b_2 < -1.20000000000000007e-54 or -5.0000000000000002e-109 < b_2 < -1.05e-178

    1. Initial program 13.0%

      \[\frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{a} \]
    2. Add Preprocessing
    3. Taylor expanded in b_2 around -inf 88.5%

      \[\leadsto \color{blue}{-0.5 \cdot \frac{c}{b\_2}} \]
    4. Step-by-step derivation
      1. associate-*r/88.5%

        \[\leadsto \color{blue}{\frac{-0.5 \cdot c}{b\_2}} \]
    5. Simplified88.5%

      \[\leadsto \color{blue}{\frac{-0.5 \cdot c}{b\_2}} \]

    if -1.20000000000000007e-54 < b_2 < -5.0000000000000002e-109 or -1.05e-178 < b_2 < 2.4e62

    1. Initial program 74.6%

      \[\frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{a} \]
    2. Add Preprocessing

    if 2.4e62 < b_2

    1. Initial program 50.9%

      \[\frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{a} \]
    2. Add Preprocessing
    3. Taylor expanded in c around 0 96.4%

      \[\leadsto \color{blue}{-2 \cdot \frac{b\_2}{a} + 0.5 \cdot \frac{c}{b\_2}} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification85.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b\_2 \leq -1.2 \cdot 10^{-54}:\\ \;\;\;\;\frac{-0.5 \cdot c}{b\_2}\\ \mathbf{elif}\;b\_2 \leq -5 \cdot 10^{-109}:\\ \;\;\;\;\frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - c \cdot a}}{a}\\ \mathbf{elif}\;b\_2 \leq -1.05 \cdot 10^{-178}:\\ \;\;\;\;\frac{-0.5 \cdot c}{b\_2}\\ \mathbf{elif}\;b\_2 \leq 2.4 \cdot 10^{+62}:\\ \;\;\;\;\frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - c \cdot a}}{a}\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot \frac{b\_2}{a} + 0.5 \cdot \frac{c}{b\_2}\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 79.7% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{-0.5 \cdot c}{b\_2}\\ t_1 := \frac{\left(-b\_2\right) - \sqrt{a \cdot \left(-c\right)}}{a}\\ \mathbf{if}\;b\_2 \leq -6.5 \cdot 10^{-59}:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;b\_2 \leq -3.8 \cdot 10^{-109}:\\ \;\;\;\;t\_1\\ \mathbf{elif}\;b\_2 \leq -1.05 \cdot 10^{-178}:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;b\_2 \leq 2.9 \cdot 10^{-89}:\\ \;\;\;\;t\_1\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot \frac{b\_2}{a} + 0.5 \cdot \frac{c}{b\_2}\\ \end{array} \end{array} \]
(FPCore (a b_2 c)
 :precision binary64
 (let* ((t_0 (/ (* -0.5 c) b_2)) (t_1 (/ (- (- b_2) (sqrt (* a (- c)))) a)))
   (if (<= b_2 -6.5e-59)
     t_0
     (if (<= b_2 -3.8e-109)
       t_1
       (if (<= b_2 -1.05e-178)
         t_0
         (if (<= b_2 2.9e-89)
           t_1
           (+ (* -2.0 (/ b_2 a)) (* 0.5 (/ c b_2)))))))))
double code(double a, double b_2, double c) {
	double t_0 = (-0.5 * c) / b_2;
	double t_1 = (-b_2 - sqrt((a * -c))) / a;
	double tmp;
	if (b_2 <= -6.5e-59) {
		tmp = t_0;
	} else if (b_2 <= -3.8e-109) {
		tmp = t_1;
	} else if (b_2 <= -1.05e-178) {
		tmp = t_0;
	} else if (b_2 <= 2.9e-89) {
		tmp = t_1;
	} else {
		tmp = (-2.0 * (b_2 / a)) + (0.5 * (c / b_2));
	}
	return tmp;
}
real(8) function code(a, b_2, c)
    real(8), intent (in) :: a
    real(8), intent (in) :: b_2
    real(8), intent (in) :: c
    real(8) :: t_0
    real(8) :: t_1
    real(8) :: tmp
    t_0 = ((-0.5d0) * c) / b_2
    t_1 = (-b_2 - sqrt((a * -c))) / a
    if (b_2 <= (-6.5d-59)) then
        tmp = t_0
    else if (b_2 <= (-3.8d-109)) then
        tmp = t_1
    else if (b_2 <= (-1.05d-178)) then
        tmp = t_0
    else if (b_2 <= 2.9d-89) then
        tmp = t_1
    else
        tmp = ((-2.0d0) * (b_2 / a)) + (0.5d0 * (c / b_2))
    end if
    code = tmp
end function
public static double code(double a, double b_2, double c) {
	double t_0 = (-0.5 * c) / b_2;
	double t_1 = (-b_2 - Math.sqrt((a * -c))) / a;
	double tmp;
	if (b_2 <= -6.5e-59) {
		tmp = t_0;
	} else if (b_2 <= -3.8e-109) {
		tmp = t_1;
	} else if (b_2 <= -1.05e-178) {
		tmp = t_0;
	} else if (b_2 <= 2.9e-89) {
		tmp = t_1;
	} else {
		tmp = (-2.0 * (b_2 / a)) + (0.5 * (c / b_2));
	}
	return tmp;
}
def code(a, b_2, c):
	t_0 = (-0.5 * c) / b_2
	t_1 = (-b_2 - math.sqrt((a * -c))) / a
	tmp = 0
	if b_2 <= -6.5e-59:
		tmp = t_0
	elif b_2 <= -3.8e-109:
		tmp = t_1
	elif b_2 <= -1.05e-178:
		tmp = t_0
	elif b_2 <= 2.9e-89:
		tmp = t_1
	else:
		tmp = (-2.0 * (b_2 / a)) + (0.5 * (c / b_2))
	return tmp
function code(a, b_2, c)
	t_0 = Float64(Float64(-0.5 * c) / b_2)
	t_1 = Float64(Float64(Float64(-b_2) - sqrt(Float64(a * Float64(-c)))) / a)
	tmp = 0.0
	if (b_2 <= -6.5e-59)
		tmp = t_0;
	elseif (b_2 <= -3.8e-109)
		tmp = t_1;
	elseif (b_2 <= -1.05e-178)
		tmp = t_0;
	elseif (b_2 <= 2.9e-89)
		tmp = t_1;
	else
		tmp = Float64(Float64(-2.0 * Float64(b_2 / a)) + Float64(0.5 * Float64(c / b_2)));
	end
	return tmp
end
function tmp_2 = code(a, b_2, c)
	t_0 = (-0.5 * c) / b_2;
	t_1 = (-b_2 - sqrt((a * -c))) / a;
	tmp = 0.0;
	if (b_2 <= -6.5e-59)
		tmp = t_0;
	elseif (b_2 <= -3.8e-109)
		tmp = t_1;
	elseif (b_2 <= -1.05e-178)
		tmp = t_0;
	elseif (b_2 <= 2.9e-89)
		tmp = t_1;
	else
		tmp = (-2.0 * (b_2 / a)) + (0.5 * (c / b_2));
	end
	tmp_2 = tmp;
end
code[a_, b$95$2_, c_] := Block[{t$95$0 = N[(N[(-0.5 * c), $MachinePrecision] / b$95$2), $MachinePrecision]}, Block[{t$95$1 = N[(N[((-b$95$2) - N[Sqrt[N[(a * (-c)), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / a), $MachinePrecision]}, If[LessEqual[b$95$2, -6.5e-59], t$95$0, If[LessEqual[b$95$2, -3.8e-109], t$95$1, If[LessEqual[b$95$2, -1.05e-178], t$95$0, If[LessEqual[b$95$2, 2.9e-89], t$95$1, N[(N[(-2.0 * N[(b$95$2 / a), $MachinePrecision]), $MachinePrecision] + N[(0.5 * N[(c / b$95$2), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{-0.5 \cdot c}{b\_2}\\
t_1 := \frac{\left(-b\_2\right) - \sqrt{a \cdot \left(-c\right)}}{a}\\
\mathbf{if}\;b\_2 \leq -6.5 \cdot 10^{-59}:\\
\;\;\;\;t\_0\\

\mathbf{elif}\;b\_2 \leq -3.8 \cdot 10^{-109}:\\
\;\;\;\;t\_1\\

\mathbf{elif}\;b\_2 \leq -1.05 \cdot 10^{-178}:\\
\;\;\;\;t\_0\\

\mathbf{elif}\;b\_2 \leq 2.9 \cdot 10^{-89}:\\
\;\;\;\;t\_1\\

\mathbf{else}:\\
\;\;\;\;-2 \cdot \frac{b\_2}{a} + 0.5 \cdot \frac{c}{b\_2}\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if b_2 < -6.50000000000000017e-59 or -3.80000000000000002e-109 < b_2 < -1.05e-178

    1. Initial program 13.0%

      \[\frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{a} \]
    2. Add Preprocessing
    3. Taylor expanded in b_2 around -inf 88.5%

      \[\leadsto \color{blue}{-0.5 \cdot \frac{c}{b\_2}} \]
    4. Step-by-step derivation
      1. associate-*r/88.5%

        \[\leadsto \color{blue}{\frac{-0.5 \cdot c}{b\_2}} \]
    5. Simplified88.5%

      \[\leadsto \color{blue}{\frac{-0.5 \cdot c}{b\_2}} \]

    if -6.50000000000000017e-59 < b_2 < -3.80000000000000002e-109 or -1.05e-178 < b_2 < 2.89999999999999992e-89

    1. Initial program 69.3%

      \[\frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{a} \]
    2. Add Preprocessing
    3. Taylor expanded in b_2 around 0 65.5%

      \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{-1 \cdot \left(a \cdot c\right)}}}{a} \]
    4. Step-by-step derivation
      1. mul-1-neg65.5%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{-a \cdot c}}}{a} \]
      2. distribute-rgt-neg-out65.5%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{a \cdot \left(-c\right)}}}{a} \]
    5. Simplified65.5%

      \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{a \cdot \left(-c\right)}}}{a} \]

    if 2.89999999999999992e-89 < b_2

    1. Initial program 61.4%

      \[\frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{a} \]
    2. Add Preprocessing
    3. Taylor expanded in c around 0 88.5%

      \[\leadsto \color{blue}{-2 \cdot \frac{b\_2}{a} + 0.5 \cdot \frac{c}{b\_2}} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification83.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b\_2 \leq -6.5 \cdot 10^{-59}:\\ \;\;\;\;\frac{-0.5 \cdot c}{b\_2}\\ \mathbf{elif}\;b\_2 \leq -3.8 \cdot 10^{-109}:\\ \;\;\;\;\frac{\left(-b\_2\right) - \sqrt{a \cdot \left(-c\right)}}{a}\\ \mathbf{elif}\;b\_2 \leq -1.05 \cdot 10^{-178}:\\ \;\;\;\;\frac{-0.5 \cdot c}{b\_2}\\ \mathbf{elif}\;b\_2 \leq 2.9 \cdot 10^{-89}:\\ \;\;\;\;\frac{\left(-b\_2\right) - \sqrt{a \cdot \left(-c\right)}}{a}\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot \frac{b\_2}{a} + 0.5 \cdot \frac{c}{b\_2}\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 80.0% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{-0.5 \cdot c}{b\_2}\\ t_1 := \frac{\sqrt{a \cdot \left(-c\right)}}{-a}\\ \mathbf{if}\;b\_2 \leq -1.7 \cdot 10^{-52}:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;b\_2 \leq -4.3 \cdot 10^{-109}:\\ \;\;\;\;t\_1\\ \mathbf{elif}\;b\_2 \leq -4 \cdot 10^{-147}:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;b\_2 \leq 9.8 \cdot 10^{-89}:\\ \;\;\;\;t\_1\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot \frac{b\_2}{a} + 0.5 \cdot \frac{c}{b\_2}\\ \end{array} \end{array} \]
(FPCore (a b_2 c)
 :precision binary64
 (let* ((t_0 (/ (* -0.5 c) b_2)) (t_1 (/ (sqrt (* a (- c))) (- a))))
   (if (<= b_2 -1.7e-52)
     t_0
     (if (<= b_2 -4.3e-109)
       t_1
       (if (<= b_2 -4e-147)
         t_0
         (if (<= b_2 9.8e-89)
           t_1
           (+ (* -2.0 (/ b_2 a)) (* 0.5 (/ c b_2)))))))))
double code(double a, double b_2, double c) {
	double t_0 = (-0.5 * c) / b_2;
	double t_1 = sqrt((a * -c)) / -a;
	double tmp;
	if (b_2 <= -1.7e-52) {
		tmp = t_0;
	} else if (b_2 <= -4.3e-109) {
		tmp = t_1;
	} else if (b_2 <= -4e-147) {
		tmp = t_0;
	} else if (b_2 <= 9.8e-89) {
		tmp = t_1;
	} else {
		tmp = (-2.0 * (b_2 / a)) + (0.5 * (c / b_2));
	}
	return tmp;
}
real(8) function code(a, b_2, c)
    real(8), intent (in) :: a
    real(8), intent (in) :: b_2
    real(8), intent (in) :: c
    real(8) :: t_0
    real(8) :: t_1
    real(8) :: tmp
    t_0 = ((-0.5d0) * c) / b_2
    t_1 = sqrt((a * -c)) / -a
    if (b_2 <= (-1.7d-52)) then
        tmp = t_0
    else if (b_2 <= (-4.3d-109)) then
        tmp = t_1
    else if (b_2 <= (-4d-147)) then
        tmp = t_0
    else if (b_2 <= 9.8d-89) then
        tmp = t_1
    else
        tmp = ((-2.0d0) * (b_2 / a)) + (0.5d0 * (c / b_2))
    end if
    code = tmp
end function
public static double code(double a, double b_2, double c) {
	double t_0 = (-0.5 * c) / b_2;
	double t_1 = Math.sqrt((a * -c)) / -a;
	double tmp;
	if (b_2 <= -1.7e-52) {
		tmp = t_0;
	} else if (b_2 <= -4.3e-109) {
		tmp = t_1;
	} else if (b_2 <= -4e-147) {
		tmp = t_0;
	} else if (b_2 <= 9.8e-89) {
		tmp = t_1;
	} else {
		tmp = (-2.0 * (b_2 / a)) + (0.5 * (c / b_2));
	}
	return tmp;
}
def code(a, b_2, c):
	t_0 = (-0.5 * c) / b_2
	t_1 = math.sqrt((a * -c)) / -a
	tmp = 0
	if b_2 <= -1.7e-52:
		tmp = t_0
	elif b_2 <= -4.3e-109:
		tmp = t_1
	elif b_2 <= -4e-147:
		tmp = t_0
	elif b_2 <= 9.8e-89:
		tmp = t_1
	else:
		tmp = (-2.0 * (b_2 / a)) + (0.5 * (c / b_2))
	return tmp
function code(a, b_2, c)
	t_0 = Float64(Float64(-0.5 * c) / b_2)
	t_1 = Float64(sqrt(Float64(a * Float64(-c))) / Float64(-a))
	tmp = 0.0
	if (b_2 <= -1.7e-52)
		tmp = t_0;
	elseif (b_2 <= -4.3e-109)
		tmp = t_1;
	elseif (b_2 <= -4e-147)
		tmp = t_0;
	elseif (b_2 <= 9.8e-89)
		tmp = t_1;
	else
		tmp = Float64(Float64(-2.0 * Float64(b_2 / a)) + Float64(0.5 * Float64(c / b_2)));
	end
	return tmp
end
function tmp_2 = code(a, b_2, c)
	t_0 = (-0.5 * c) / b_2;
	t_1 = sqrt((a * -c)) / -a;
	tmp = 0.0;
	if (b_2 <= -1.7e-52)
		tmp = t_0;
	elseif (b_2 <= -4.3e-109)
		tmp = t_1;
	elseif (b_2 <= -4e-147)
		tmp = t_0;
	elseif (b_2 <= 9.8e-89)
		tmp = t_1;
	else
		tmp = (-2.0 * (b_2 / a)) + (0.5 * (c / b_2));
	end
	tmp_2 = tmp;
end
code[a_, b$95$2_, c_] := Block[{t$95$0 = N[(N[(-0.5 * c), $MachinePrecision] / b$95$2), $MachinePrecision]}, Block[{t$95$1 = N[(N[Sqrt[N[(a * (-c)), $MachinePrecision]], $MachinePrecision] / (-a)), $MachinePrecision]}, If[LessEqual[b$95$2, -1.7e-52], t$95$0, If[LessEqual[b$95$2, -4.3e-109], t$95$1, If[LessEqual[b$95$2, -4e-147], t$95$0, If[LessEqual[b$95$2, 9.8e-89], t$95$1, N[(N[(-2.0 * N[(b$95$2 / a), $MachinePrecision]), $MachinePrecision] + N[(0.5 * N[(c / b$95$2), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{-0.5 \cdot c}{b\_2}\\
t_1 := \frac{\sqrt{a \cdot \left(-c\right)}}{-a}\\
\mathbf{if}\;b\_2 \leq -1.7 \cdot 10^{-52}:\\
\;\;\;\;t\_0\\

\mathbf{elif}\;b\_2 \leq -4.3 \cdot 10^{-109}:\\
\;\;\;\;t\_1\\

\mathbf{elif}\;b\_2 \leq -4 \cdot 10^{-147}:\\
\;\;\;\;t\_0\\

\mathbf{elif}\;b\_2 \leq 9.8 \cdot 10^{-89}:\\
\;\;\;\;t\_1\\

\mathbf{else}:\\
\;\;\;\;-2 \cdot \frac{b\_2}{a} + 0.5 \cdot \frac{c}{b\_2}\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if b_2 < -1.70000000000000009e-52 or -4.2999999999999997e-109 < b_2 < -3.9999999999999999e-147

    1. Initial program 12.3%

      \[\frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{a} \]
    2. Add Preprocessing
    3. Taylor expanded in b_2 around -inf 89.3%

      \[\leadsto \color{blue}{-0.5 \cdot \frac{c}{b\_2}} \]
    4. Step-by-step derivation
      1. associate-*r/89.3%

        \[\leadsto \color{blue}{\frac{-0.5 \cdot c}{b\_2}} \]
    5. Simplified89.3%

      \[\leadsto \color{blue}{\frac{-0.5 \cdot c}{b\_2}} \]

    if -1.70000000000000009e-52 < b_2 < -4.2999999999999997e-109 or -3.9999999999999999e-147 < b_2 < 9.8e-89

    1. Initial program 68.7%

      \[\frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{a} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. prod-diff68.3%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{\mathsf{fma}\left(b\_2, b\_2, -c \cdot a\right) + \mathsf{fma}\left(-c, a, c \cdot a\right)}}}{a} \]
      2. *-commutative68.3%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\mathsf{fma}\left(b\_2, b\_2, -\color{blue}{a \cdot c}\right) + \mathsf{fma}\left(-c, a, c \cdot a\right)}}{a} \]
      3. fmm-def68.3%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{\left(b\_2 \cdot b\_2 - a \cdot c\right)} + \mathsf{fma}\left(-c, a, c \cdot a\right)}}{a} \]
      4. prod-diff68.3%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{\left(\mathsf{fma}\left(b\_2, b\_2, -c \cdot a\right) + \mathsf{fma}\left(-c, a, c \cdot a\right)\right)} + \mathsf{fma}\left(-c, a, c \cdot a\right)}}{a} \]
      5. *-commutative68.3%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\left(\mathsf{fma}\left(b\_2, b\_2, -\color{blue}{a \cdot c}\right) + \mathsf{fma}\left(-c, a, c \cdot a\right)\right) + \mathsf{fma}\left(-c, a, c \cdot a\right)}}{a} \]
      6. fmm-def68.3%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\left(\color{blue}{\left(b\_2 \cdot b\_2 - a \cdot c\right)} + \mathsf{fma}\left(-c, a, c \cdot a\right)\right) + \mathsf{fma}\left(-c, a, c \cdot a\right)}}{a} \]
      7. associate-+l+68.3%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{\left(b\_2 \cdot b\_2 - a \cdot c\right) + \left(\mathsf{fma}\left(-c, a, c \cdot a\right) + \mathsf{fma}\left(-c, a, c \cdot a\right)\right)}}}{a} \]
      8. pow268.3%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\left(\color{blue}{{b\_2}^{2}} - a \cdot c\right) + \left(\mathsf{fma}\left(-c, a, c \cdot a\right) + \mathsf{fma}\left(-c, a, c \cdot a\right)\right)}}{a} \]
      9. *-commutative68.3%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\left({b\_2}^{2} - a \cdot c\right) + \left(\mathsf{fma}\left(-c, a, \color{blue}{a \cdot c}\right) + \mathsf{fma}\left(-c, a, c \cdot a\right)\right)}}{a} \]
      10. fma-undefine68.3%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\left({b\_2}^{2} - a \cdot c\right) + \left(\color{blue}{\left(\left(-c\right) \cdot a + a \cdot c\right)} + \mathsf{fma}\left(-c, a, c \cdot a\right)\right)}}{a} \]
      11. distribute-lft-neg-in68.3%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\left({b\_2}^{2} - a \cdot c\right) + \left(\left(\color{blue}{\left(-c \cdot a\right)} + a \cdot c\right) + \mathsf{fma}\left(-c, a, c \cdot a\right)\right)}}{a} \]
      12. *-commutative68.3%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\left({b\_2}^{2} - a \cdot c\right) + \left(\left(\left(-\color{blue}{a \cdot c}\right) + a \cdot c\right) + \mathsf{fma}\left(-c, a, c \cdot a\right)\right)}}{a} \]
      13. distribute-rgt-neg-in68.3%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\left({b\_2}^{2} - a \cdot c\right) + \left(\left(\color{blue}{a \cdot \left(-c\right)} + a \cdot c\right) + \mathsf{fma}\left(-c, a, c \cdot a\right)\right)}}{a} \]
      14. fma-define68.3%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\left({b\_2}^{2} - a \cdot c\right) + \left(\color{blue}{\mathsf{fma}\left(a, -c, a \cdot c\right)} + \mathsf{fma}\left(-c, a, c \cdot a\right)\right)}}{a} \]
      15. *-commutative68.3%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\left({b\_2}^{2} - a \cdot c\right) + \left(\mathsf{fma}\left(a, -c, a \cdot c\right) + \mathsf{fma}\left(-c, a, \color{blue}{a \cdot c}\right)\right)}}{a} \]
      16. fma-undefine68.3%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\left({b\_2}^{2} - a \cdot c\right) + \left(\mathsf{fma}\left(a, -c, a \cdot c\right) + \color{blue}{\left(\left(-c\right) \cdot a + a \cdot c\right)}\right)}}{a} \]
      17. distribute-lft-neg-in68.3%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\left({b\_2}^{2} - a \cdot c\right) + \left(\mathsf{fma}\left(a, -c, a \cdot c\right) + \left(\color{blue}{\left(-c \cdot a\right)} + a \cdot c\right)\right)}}{a} \]
      18. *-commutative68.3%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\left({b\_2}^{2} - a \cdot c\right) + \left(\mathsf{fma}\left(a, -c, a \cdot c\right) + \left(\left(-\color{blue}{a \cdot c}\right) + a \cdot c\right)\right)}}{a} \]
      19. distribute-rgt-neg-in68.3%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\left({b\_2}^{2} - a \cdot c\right) + \left(\mathsf{fma}\left(a, -c, a \cdot c\right) + \left(\color{blue}{a \cdot \left(-c\right)} + a \cdot c\right)\right)}}{a} \]
    4. Applied egg-rr68.3%

      \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{\left({b\_2}^{2} - a \cdot c\right) + \left(\mathsf{fma}\left(a, -c, a \cdot c\right) + \mathsf{fma}\left(a, -c, a \cdot c\right)\right)}}}{a} \]
    5. Step-by-step derivation
      1. count-268.3%

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\left({b\_2}^{2} - a \cdot c\right) + \color{blue}{2 \cdot \mathsf{fma}\left(a, -c, a \cdot c\right)}}}{a} \]
    6. Simplified68.3%

      \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{\left({b\_2}^{2} - a \cdot c\right) + 2 \cdot \mathsf{fma}\left(a, -c, a \cdot c\right)}}}{a} \]
    7. Taylor expanded in c around inf 64.0%

      \[\leadsto \color{blue}{-1 \cdot \left(\frac{1}{a} \cdot \sqrt{c \cdot \left(2 \cdot \left(a + -1 \cdot a\right) - a\right)}\right)} \]
    8. Step-by-step derivation
      1. mul-1-neg64.0%

        \[\leadsto \color{blue}{-\frac{1}{a} \cdot \sqrt{c \cdot \left(2 \cdot \left(a + -1 \cdot a\right) - a\right)}} \]
      2. *-commutative64.0%

        \[\leadsto -\color{blue}{\sqrt{c \cdot \left(2 \cdot \left(a + -1 \cdot a\right) - a\right)} \cdot \frac{1}{a}} \]
      3. *-commutative64.0%

        \[\leadsto -\sqrt{c \cdot \left(\color{blue}{\left(a + -1 \cdot a\right) \cdot 2} - a\right)} \cdot \frac{1}{a} \]
      4. distribute-rgt1-in64.0%

        \[\leadsto -\sqrt{c \cdot \left(\color{blue}{\left(\left(-1 + 1\right) \cdot a\right)} \cdot 2 - a\right)} \cdot \frac{1}{a} \]
      5. metadata-eval64.0%

        \[\leadsto -\sqrt{c \cdot \left(\left(\color{blue}{0} \cdot a\right) \cdot 2 - a\right)} \cdot \frac{1}{a} \]
    9. Simplified64.0%

      \[\leadsto \color{blue}{-\sqrt{c \cdot \left(\left(0 \cdot a\right) \cdot 2 - a\right)} \cdot \frac{1}{a}} \]
    10. Step-by-step derivation
      1. un-div-inv64.1%

        \[\leadsto -\color{blue}{\frac{\sqrt{c \cdot \left(\left(0 \cdot a\right) \cdot 2 - a\right)}}{a}} \]
      2. add-log-exp4.2%

        \[\leadsto -\frac{\sqrt{c \cdot \color{blue}{\log \left(e^{\left(0 \cdot a\right) \cdot 2 - a}\right)}}}{a} \]
      3. *-commutative4.2%

        \[\leadsto -\frac{\sqrt{c \cdot \log \left(e^{\color{blue}{2 \cdot \left(0 \cdot a\right)} - a}\right)}}{a} \]
      4. mul0-lft4.2%

        \[\leadsto -\frac{\sqrt{c \cdot \log \left(e^{2 \cdot \color{blue}{0} - a}\right)}}{a} \]
      5. metadata-eval4.2%

        \[\leadsto -\frac{\sqrt{c \cdot \log \left(e^{\color{blue}{0} - a}\right)}}{a} \]
      6. mul0-lft4.2%

        \[\leadsto -\frac{\sqrt{c \cdot \log \left(e^{\color{blue}{0 \cdot a} - a}\right)}}{a} \]
      7. exp-diff4.2%

        \[\leadsto -\frac{\sqrt{c \cdot \log \color{blue}{\left(\frac{e^{0 \cdot a}}{e^{a}}\right)}}}{a} \]
      8. mul0-lft4.2%

        \[\leadsto -\frac{\sqrt{c \cdot \log \left(\frac{e^{\color{blue}{0}}}{e^{a}}\right)}}{a} \]
      9. 1-exp4.2%

        \[\leadsto -\frac{\sqrt{c \cdot \log \left(\frac{\color{blue}{1}}{e^{a}}\right)}}{a} \]
      10. neg-log4.2%

        \[\leadsto -\frac{\sqrt{c \cdot \color{blue}{\left(-\log \left(e^{a}\right)\right)}}}{a} \]
      11. add-log-exp64.1%

        \[\leadsto -\frac{\sqrt{c \cdot \left(-\color{blue}{a}\right)}}{a} \]
    11. Applied egg-rr64.1%

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

    if 9.8e-89 < b_2

    1. Initial program 61.4%

      \[\frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{a} \]
    2. Add Preprocessing
    3. Taylor expanded in c around 0 88.5%

      \[\leadsto \color{blue}{-2 \cdot \frac{b\_2}{a} + 0.5 \cdot \frac{c}{b\_2}} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification82.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b\_2 \leq -1.7 \cdot 10^{-52}:\\ \;\;\;\;\frac{-0.5 \cdot c}{b\_2}\\ \mathbf{elif}\;b\_2 \leq -4.3 \cdot 10^{-109}:\\ \;\;\;\;\frac{\sqrt{a \cdot \left(-c\right)}}{-a}\\ \mathbf{elif}\;b\_2 \leq -4 \cdot 10^{-147}:\\ \;\;\;\;\frac{-0.5 \cdot c}{b\_2}\\ \mathbf{elif}\;b\_2 \leq 9.8 \cdot 10^{-89}:\\ \;\;\;\;\frac{\sqrt{a \cdot \left(-c\right)}}{-a}\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot \frac{b\_2}{a} + 0.5 \cdot \frac{c}{b\_2}\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 68.3% accurate, 7.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b\_2 \leq -5 \cdot 10^{-310}:\\ \;\;\;\;\frac{-0.5 \cdot c}{b\_2}\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot \frac{b\_2}{a} + 0.5 \cdot \frac{c}{b\_2}\\ \end{array} \end{array} \]
(FPCore (a b_2 c)
 :precision binary64
 (if (<= b_2 -5e-310)
   (/ (* -0.5 c) b_2)
   (+ (* -2.0 (/ b_2 a)) (* 0.5 (/ c b_2)))))
double code(double a, double b_2, double c) {
	double tmp;
	if (b_2 <= -5e-310) {
		tmp = (-0.5 * c) / b_2;
	} else {
		tmp = (-2.0 * (b_2 / a)) + (0.5 * (c / b_2));
	}
	return tmp;
}
real(8) function code(a, b_2, c)
    real(8), intent (in) :: a
    real(8), intent (in) :: b_2
    real(8), intent (in) :: c
    real(8) :: tmp
    if (b_2 <= (-5d-310)) then
        tmp = ((-0.5d0) * c) / b_2
    else
        tmp = ((-2.0d0) * (b_2 / a)) + (0.5d0 * (c / b_2))
    end if
    code = tmp
end function
public static double code(double a, double b_2, double c) {
	double tmp;
	if (b_2 <= -5e-310) {
		tmp = (-0.5 * c) / b_2;
	} else {
		tmp = (-2.0 * (b_2 / a)) + (0.5 * (c / b_2));
	}
	return tmp;
}
def code(a, b_2, c):
	tmp = 0
	if b_2 <= -5e-310:
		tmp = (-0.5 * c) / b_2
	else:
		tmp = (-2.0 * (b_2 / a)) + (0.5 * (c / b_2))
	return tmp
function code(a, b_2, c)
	tmp = 0.0
	if (b_2 <= -5e-310)
		tmp = Float64(Float64(-0.5 * c) / b_2);
	else
		tmp = Float64(Float64(-2.0 * Float64(b_2 / a)) + Float64(0.5 * Float64(c / b_2)));
	end
	return tmp
end
function tmp_2 = code(a, b_2, c)
	tmp = 0.0;
	if (b_2 <= -5e-310)
		tmp = (-0.5 * c) / b_2;
	else
		tmp = (-2.0 * (b_2 / a)) + (0.5 * (c / b_2));
	end
	tmp_2 = tmp;
end
code[a_, b$95$2_, c_] := If[LessEqual[b$95$2, -5e-310], N[(N[(-0.5 * c), $MachinePrecision] / b$95$2), $MachinePrecision], N[(N[(-2.0 * N[(b$95$2 / a), $MachinePrecision]), $MachinePrecision] + N[(0.5 * N[(c / b$95$2), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b\_2 \leq -5 \cdot 10^{-310}:\\
\;\;\;\;\frac{-0.5 \cdot c}{b\_2}\\

\mathbf{else}:\\
\;\;\;\;-2 \cdot \frac{b\_2}{a} + 0.5 \cdot \frac{c}{b\_2}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if b_2 < -4.999999999999985e-310

    1. Initial program 22.6%

      \[\frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{a} \]
    2. Add Preprocessing
    3. Taylor expanded in b_2 around -inf 73.4%

      \[\leadsto \color{blue}{-0.5 \cdot \frac{c}{b\_2}} \]
    4. Step-by-step derivation
      1. associate-*r/73.4%

        \[\leadsto \color{blue}{\frac{-0.5 \cdot c}{b\_2}} \]
    5. Simplified73.4%

      \[\leadsto \color{blue}{\frac{-0.5 \cdot c}{b\_2}} \]

    if -4.999999999999985e-310 < b_2

    1. Initial program 65.3%

      \[\frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{a} \]
    2. Add Preprocessing
    3. Taylor expanded in c around 0 66.4%

      \[\leadsto \color{blue}{-2 \cdot \frac{b\_2}{a} + 0.5 \cdot \frac{c}{b\_2}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification69.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b\_2 \leq -5 \cdot 10^{-310}:\\ \;\;\;\;\frac{-0.5 \cdot c}{b\_2}\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot \frac{b\_2}{a} + 0.5 \cdot \frac{c}{b\_2}\\ \end{array} \]
  5. Add Preprocessing

Alternative 5: 43.7% accurate, 11.2× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b\_2 \leq -540000000000:\\ \;\;\;\;0.5 \cdot \frac{c}{b\_2}\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot \frac{b\_2}{a}\\ \end{array} \end{array} \]
(FPCore (a b_2 c)
 :precision binary64
 (if (<= b_2 -540000000000.0) (* 0.5 (/ c b_2)) (* -2.0 (/ b_2 a))))
double code(double a, double b_2, double c) {
	double tmp;
	if (b_2 <= -540000000000.0) {
		tmp = 0.5 * (c / b_2);
	} else {
		tmp = -2.0 * (b_2 / a);
	}
	return tmp;
}
real(8) function code(a, b_2, c)
    real(8), intent (in) :: a
    real(8), intent (in) :: b_2
    real(8), intent (in) :: c
    real(8) :: tmp
    if (b_2 <= (-540000000000.0d0)) then
        tmp = 0.5d0 * (c / b_2)
    else
        tmp = (-2.0d0) * (b_2 / a)
    end if
    code = tmp
end function
public static double code(double a, double b_2, double c) {
	double tmp;
	if (b_2 <= -540000000000.0) {
		tmp = 0.5 * (c / b_2);
	} else {
		tmp = -2.0 * (b_2 / a);
	}
	return tmp;
}
def code(a, b_2, c):
	tmp = 0
	if b_2 <= -540000000000.0:
		tmp = 0.5 * (c / b_2)
	else:
		tmp = -2.0 * (b_2 / a)
	return tmp
function code(a, b_2, c)
	tmp = 0.0
	if (b_2 <= -540000000000.0)
		tmp = Float64(0.5 * Float64(c / b_2));
	else
		tmp = Float64(-2.0 * Float64(b_2 / a));
	end
	return tmp
end
function tmp_2 = code(a, b_2, c)
	tmp = 0.0;
	if (b_2 <= -540000000000.0)
		tmp = 0.5 * (c / b_2);
	else
		tmp = -2.0 * (b_2 / a);
	end
	tmp_2 = tmp;
end
code[a_, b$95$2_, c_] := If[LessEqual[b$95$2, -540000000000.0], N[(0.5 * N[(c / b$95$2), $MachinePrecision]), $MachinePrecision], N[(-2.0 * N[(b$95$2 / a), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b\_2 \leq -540000000000:\\
\;\;\;\;0.5 \cdot \frac{c}{b\_2}\\

\mathbf{else}:\\
\;\;\;\;-2 \cdot \frac{b\_2}{a}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if b_2 < -5.4e11

    1. Initial program 9.7%

      \[\frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{a} \]
    2. Add Preprocessing
    3. Taylor expanded in a around 0 2.2%

      \[\leadsto \frac{\color{blue}{0.5 \cdot \frac{a \cdot c}{b\_2} - 2 \cdot b\_2}}{a} \]
    4. Taylor expanded in a around inf 30.6%

      \[\leadsto \color{blue}{0.5 \cdot \frac{c}{b\_2}} \]

    if -5.4e11 < b_2

    1. Initial program 58.8%

      \[\frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{a} \]
    2. Add Preprocessing
    3. Taylor expanded in b_2 around inf 48.9%

      \[\leadsto \color{blue}{-2 \cdot \frac{b\_2}{a}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification43.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b\_2 \leq -540000000000:\\ \;\;\;\;0.5 \cdot \frac{c}{b\_2}\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot \frac{b\_2}{a}\\ \end{array} \]
  5. Add Preprocessing

Alternative 6: 68.1% accurate, 11.2× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b\_2 \leq -5 \cdot 10^{-310}:\\ \;\;\;\;\frac{-0.5 \cdot c}{b\_2}\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot \frac{b\_2}{a}\\ \end{array} \end{array} \]
(FPCore (a b_2 c)
 :precision binary64
 (if (<= b_2 -5e-310) (/ (* -0.5 c) b_2) (* -2.0 (/ b_2 a))))
double code(double a, double b_2, double c) {
	double tmp;
	if (b_2 <= -5e-310) {
		tmp = (-0.5 * c) / b_2;
	} else {
		tmp = -2.0 * (b_2 / a);
	}
	return tmp;
}
real(8) function code(a, b_2, c)
    real(8), intent (in) :: a
    real(8), intent (in) :: b_2
    real(8), intent (in) :: c
    real(8) :: tmp
    if (b_2 <= (-5d-310)) then
        tmp = ((-0.5d0) * c) / b_2
    else
        tmp = (-2.0d0) * (b_2 / a)
    end if
    code = tmp
end function
public static double code(double a, double b_2, double c) {
	double tmp;
	if (b_2 <= -5e-310) {
		tmp = (-0.5 * c) / b_2;
	} else {
		tmp = -2.0 * (b_2 / a);
	}
	return tmp;
}
def code(a, b_2, c):
	tmp = 0
	if b_2 <= -5e-310:
		tmp = (-0.5 * c) / b_2
	else:
		tmp = -2.0 * (b_2 / a)
	return tmp
function code(a, b_2, c)
	tmp = 0.0
	if (b_2 <= -5e-310)
		tmp = Float64(Float64(-0.5 * c) / b_2);
	else
		tmp = Float64(-2.0 * Float64(b_2 / a));
	end
	return tmp
end
function tmp_2 = code(a, b_2, c)
	tmp = 0.0;
	if (b_2 <= -5e-310)
		tmp = (-0.5 * c) / b_2;
	else
		tmp = -2.0 * (b_2 / a);
	end
	tmp_2 = tmp;
end
code[a_, b$95$2_, c_] := If[LessEqual[b$95$2, -5e-310], N[(N[(-0.5 * c), $MachinePrecision] / b$95$2), $MachinePrecision], N[(-2.0 * N[(b$95$2 / a), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b\_2 \leq -5 \cdot 10^{-310}:\\
\;\;\;\;\frac{-0.5 \cdot c}{b\_2}\\

\mathbf{else}:\\
\;\;\;\;-2 \cdot \frac{b\_2}{a}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if b_2 < -4.999999999999985e-310

    1. Initial program 22.6%

      \[\frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{a} \]
    2. Add Preprocessing
    3. Taylor expanded in b_2 around -inf 73.4%

      \[\leadsto \color{blue}{-0.5 \cdot \frac{c}{b\_2}} \]
    4. Step-by-step derivation
      1. associate-*r/73.4%

        \[\leadsto \color{blue}{\frac{-0.5 \cdot c}{b\_2}} \]
    5. Simplified73.4%

      \[\leadsto \color{blue}{\frac{-0.5 \cdot c}{b\_2}} \]

    if -4.999999999999985e-310 < b_2

    1. Initial program 65.3%

      \[\frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{a} \]
    2. Add Preprocessing
    3. Taylor expanded in b_2 around inf 66.3%

      \[\leadsto \color{blue}{-2 \cdot \frac{b\_2}{a}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification69.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b\_2 \leq -5 \cdot 10^{-310}:\\ \;\;\;\;\frac{-0.5 \cdot c}{b\_2}\\ \mathbf{else}:\\ \;\;\;\;-2 \cdot \frac{b\_2}{a}\\ \end{array} \]
  5. Add Preprocessing

Alternative 7: 35.8% accurate, 22.4× speedup?

\[\begin{array}{l} \\ -2 \cdot \frac{b\_2}{a} \end{array} \]
(FPCore (a b_2 c) :precision binary64 (* -2.0 (/ b_2 a)))
double code(double a, double b_2, double c) {
	return -2.0 * (b_2 / a);
}
real(8) function code(a, b_2, c)
    real(8), intent (in) :: a
    real(8), intent (in) :: b_2
    real(8), intent (in) :: c
    code = (-2.0d0) * (b_2 / a)
end function
public static double code(double a, double b_2, double c) {
	return -2.0 * (b_2 / a);
}
def code(a, b_2, c):
	return -2.0 * (b_2 / a)
function code(a, b_2, c)
	return Float64(-2.0 * Float64(b_2 / a))
end
function tmp = code(a, b_2, c)
	tmp = -2.0 * (b_2 / a);
end
code[a_, b$95$2_, c_] := N[(-2.0 * N[(b$95$2 / a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
-2 \cdot \frac{b\_2}{a}
\end{array}
Derivation
  1. Initial program 44.4%

    \[\frac{\left(-b\_2\right) - \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{a} \]
  2. Add Preprocessing
  3. Taylor expanded in b_2 around inf 35.2%

    \[\leadsto \color{blue}{-2 \cdot \frac{b\_2}{a}} \]
  4. Final simplification35.2%

    \[\leadsto -2 \cdot \frac{b\_2}{a} \]
  5. Add Preprocessing

Developer target: 99.6% accurate, 0.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \sqrt{\left|a\right|} \cdot \sqrt{\left|c\right|}\\ t_1 := \begin{array}{l} \mathbf{if}\;\mathsf{copysign}\left(a, c\right) = a:\\ \;\;\;\;\sqrt{\left|b\_2\right| - t\_0} \cdot \sqrt{\left|b\_2\right| + t\_0}\\ \mathbf{else}:\\ \;\;\;\;\mathsf{hypot}\left(b\_2, t\_0\right)\\ \end{array}\\ \mathbf{if}\;b\_2 < 0:\\ \;\;\;\;\frac{c}{t\_1 - b\_2}\\ \mathbf{else}:\\ \;\;\;\;\frac{b\_2 + t\_1}{-a}\\ \end{array} \end{array} \]
(FPCore (a b_2 c)
 :precision binary64
 (let* ((t_0 (* (sqrt (fabs a)) (sqrt (fabs c))))
        (t_1
         (if (== (copysign a c) a)
           (* (sqrt (- (fabs b_2) t_0)) (sqrt (+ (fabs b_2) t_0)))
           (hypot b_2 t_0))))
   (if (< b_2 0.0) (/ c (- t_1 b_2)) (/ (+ b_2 t_1) (- a)))))
double code(double a, double b_2, double c) {
	double t_0 = sqrt(fabs(a)) * sqrt(fabs(c));
	double tmp;
	if (copysign(a, c) == a) {
		tmp = sqrt((fabs(b_2) - t_0)) * sqrt((fabs(b_2) + t_0));
	} else {
		tmp = hypot(b_2, t_0);
	}
	double t_1 = tmp;
	double tmp_1;
	if (b_2 < 0.0) {
		tmp_1 = c / (t_1 - b_2);
	} else {
		tmp_1 = (b_2 + t_1) / -a;
	}
	return tmp_1;
}
public static double code(double a, double b_2, double c) {
	double t_0 = Math.sqrt(Math.abs(a)) * Math.sqrt(Math.abs(c));
	double tmp;
	if (Math.copySign(a, c) == a) {
		tmp = Math.sqrt((Math.abs(b_2) - t_0)) * Math.sqrt((Math.abs(b_2) + t_0));
	} else {
		tmp = Math.hypot(b_2, t_0);
	}
	double t_1 = tmp;
	double tmp_1;
	if (b_2 < 0.0) {
		tmp_1 = c / (t_1 - b_2);
	} else {
		tmp_1 = (b_2 + t_1) / -a;
	}
	return tmp_1;
}
def code(a, b_2, c):
	t_0 = math.sqrt(math.fabs(a)) * math.sqrt(math.fabs(c))
	tmp = 0
	if math.copysign(a, c) == a:
		tmp = math.sqrt((math.fabs(b_2) - t_0)) * math.sqrt((math.fabs(b_2) + t_0))
	else:
		tmp = math.hypot(b_2, t_0)
	t_1 = tmp
	tmp_1 = 0
	if b_2 < 0.0:
		tmp_1 = c / (t_1 - b_2)
	else:
		tmp_1 = (b_2 + t_1) / -a
	return tmp_1
function code(a, b_2, c)
	t_0 = Float64(sqrt(abs(a)) * sqrt(abs(c)))
	tmp = 0.0
	if (copysign(a, c) == a)
		tmp = Float64(sqrt(Float64(abs(b_2) - t_0)) * sqrt(Float64(abs(b_2) + t_0)));
	else
		tmp = hypot(b_2, t_0);
	end
	t_1 = tmp
	tmp_1 = 0.0
	if (b_2 < 0.0)
		tmp_1 = Float64(c / Float64(t_1 - b_2));
	else
		tmp_1 = Float64(Float64(b_2 + t_1) / Float64(-a));
	end
	return tmp_1
end
function tmp_3 = code(a, b_2, c)
	t_0 = sqrt(abs(a)) * sqrt(abs(c));
	tmp = 0.0;
	if ((sign(c) * abs(a)) == a)
		tmp = sqrt((abs(b_2) - t_0)) * sqrt((abs(b_2) + t_0));
	else
		tmp = hypot(b_2, t_0);
	end
	t_1 = tmp;
	tmp_2 = 0.0;
	if (b_2 < 0.0)
		tmp_2 = c / (t_1 - b_2);
	else
		tmp_2 = (b_2 + t_1) / -a;
	end
	tmp_3 = tmp_2;
end
code[a_, b$95$2_, c_] := Block[{t$95$0 = N[(N[Sqrt[N[Abs[a], $MachinePrecision]], $MachinePrecision] * N[Sqrt[N[Abs[c], $MachinePrecision]], $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = If[Equal[N[With[{TMP1 = Abs[a], TMP2 = Sign[c]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision], a], N[(N[Sqrt[N[(N[Abs[b$95$2], $MachinePrecision] - t$95$0), $MachinePrecision]], $MachinePrecision] * N[Sqrt[N[(N[Abs[b$95$2], $MachinePrecision] + t$95$0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[Sqrt[b$95$2 ^ 2 + t$95$0 ^ 2], $MachinePrecision]]}, If[Less[b$95$2, 0.0], N[(c / N[(t$95$1 - b$95$2), $MachinePrecision]), $MachinePrecision], N[(N[(b$95$2 + t$95$1), $MachinePrecision] / (-a)), $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \sqrt{\left|a\right|} \cdot \sqrt{\left|c\right|}\\
t_1 := \begin{array}{l}
\mathbf{if}\;\mathsf{copysign}\left(a, c\right) = a:\\
\;\;\;\;\sqrt{\left|b\_2\right| - t\_0} \cdot \sqrt{\left|b\_2\right| + t\_0}\\

\mathbf{else}:\\
\;\;\;\;\mathsf{hypot}\left(b\_2, t\_0\right)\\


\end{array}\\
\mathbf{if}\;b\_2 < 0:\\
\;\;\;\;\frac{c}{t\_1 - b\_2}\\

\mathbf{else}:\\
\;\;\;\;\frac{b\_2 + t\_1}{-a}\\


\end{array}
\end{array}

Reproduce

?
herbie shell --seed 2024079 
(FPCore (a b_2 c)
  :name "quad2m (problem 3.2.1, negative)"
  :precision binary64
  :herbie-expected 10

  :alt
  (if (< b_2 0.0) (/ c (- (if (== (copysign a c) a) (* (sqrt (- (fabs b_2) (* (sqrt (fabs a)) (sqrt (fabs c))))) (sqrt (+ (fabs b_2) (* (sqrt (fabs a)) (sqrt (fabs c)))))) (hypot b_2 (* (sqrt (fabs a)) (sqrt (fabs c))))) b_2)) (/ (+ b_2 (if (== (copysign a c) a) (* (sqrt (- (fabs b_2) (* (sqrt (fabs a)) (sqrt (fabs c))))) (sqrt (+ (fabs b_2) (* (sqrt (fabs a)) (sqrt (fabs c)))))) (hypot b_2 (* (sqrt (fabs a)) (sqrt (fabs c)))))) (- a)))

  (/ (- (- b_2) (sqrt (- (* b_2 b_2) (* a c)))) a))