quad2m (problem 3.2.1, negative)

Percentage Accurate: 51.2% → 85.4%
Time: 7.9s
Alternatives: 7
Speedup: 1.7×

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: 51.2% 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: 85.4% accurate, 0.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b\_2 \leq -3 \cdot 10^{-93}:\\ \;\;\;\;\frac{c}{b\_2} \cdot -0.5\\ \mathbf{elif}\;b\_2 \leq 10^{+126}:\\ \;\;\;\;\frac{\sqrt{b\_2 \cdot b\_2 - c \cdot a} + b\_2}{-a}\\ \mathbf{else}:\\ \;\;\;\;\frac{-2 \cdot b\_2}{a}\\ \end{array} \end{array} \]
(FPCore (a b_2 c)
 :precision binary64
 (if (<= b_2 -3e-93)
   (* (/ c b_2) -0.5)
   (if (<= b_2 1e+126)
     (/ (+ (sqrt (- (* b_2 b_2) (* c a))) b_2) (- a))
     (/ (* -2.0 b_2) a))))
double code(double a, double b_2, double c) {
	double tmp;
	if (b_2 <= -3e-93) {
		tmp = (c / b_2) * -0.5;
	} else if (b_2 <= 1e+126) {
		tmp = (sqrt(((b_2 * b_2) - (c * a))) + b_2) / -a;
	} 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 <= (-3d-93)) then
        tmp = (c / b_2) * (-0.5d0)
    else if (b_2 <= 1d+126) then
        tmp = (sqrt(((b_2 * b_2) - (c * a))) + b_2) / -a
    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 <= -3e-93) {
		tmp = (c / b_2) * -0.5;
	} else if (b_2 <= 1e+126) {
		tmp = (Math.sqrt(((b_2 * b_2) - (c * a))) + b_2) / -a;
	} else {
		tmp = (-2.0 * b_2) / a;
	}
	return tmp;
}
def code(a, b_2, c):
	tmp = 0
	if b_2 <= -3e-93:
		tmp = (c / b_2) * -0.5
	elif b_2 <= 1e+126:
		tmp = (math.sqrt(((b_2 * b_2) - (c * a))) + b_2) / -a
	else:
		tmp = (-2.0 * b_2) / a
	return tmp
function code(a, b_2, c)
	tmp = 0.0
	if (b_2 <= -3e-93)
		tmp = Float64(Float64(c / b_2) * -0.5);
	elseif (b_2 <= 1e+126)
		tmp = Float64(Float64(sqrt(Float64(Float64(b_2 * b_2) - Float64(c * a))) + b_2) / Float64(-a));
	else
		tmp = Float64(Float64(-2.0 * b_2) / a);
	end
	return tmp
end
function tmp_2 = code(a, b_2, c)
	tmp = 0.0;
	if (b_2 <= -3e-93)
		tmp = (c / b_2) * -0.5;
	elseif (b_2 <= 1e+126)
		tmp = (sqrt(((b_2 * b_2) - (c * a))) + b_2) / -a;
	else
		tmp = (-2.0 * b_2) / a;
	end
	tmp_2 = tmp;
end
code[a_, b$95$2_, c_] := If[LessEqual[b$95$2, -3e-93], N[(N[(c / b$95$2), $MachinePrecision] * -0.5), $MachinePrecision], If[LessEqual[b$95$2, 1e+126], N[(N[(N[Sqrt[N[(N[(b$95$2 * b$95$2), $MachinePrecision] - N[(c * a), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + b$95$2), $MachinePrecision] / (-a)), $MachinePrecision], N[(N[(-2.0 * b$95$2), $MachinePrecision] / a), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b\_2 \leq -3 \cdot 10^{-93}:\\
\;\;\;\;\frac{c}{b\_2} \cdot -0.5\\

\mathbf{elif}\;b\_2 \leq 10^{+126}:\\
\;\;\;\;\frac{\sqrt{b\_2 \cdot b\_2 - c \cdot a} + b\_2}{-a}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if b_2 < -3.0000000000000001e-93

    1. Initial program 16.2%

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

      \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{c}{b\_2}} \]
    4. Step-by-step derivation
      1. lower-*.f64N/A

        \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{c}{b\_2}} \]
      2. lower-/.f6487.3

        \[\leadsto -0.5 \cdot \color{blue}{\frac{c}{b\_2}} \]
    5. Applied rewrites87.3%

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

    if -3.0000000000000001e-93 < b_2 < 9.99999999999999925e125

    1. Initial program 80.8%

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

    if 9.99999999999999925e125 < b_2

    1. Initial program 54.8%

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

      \[\leadsto \frac{\color{blue}{-2 \cdot b\_2}}{a} \]
    4. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{\color{blue}{b\_2 \cdot -2}}{a} \]
      2. lower-*.f6498.2

        \[\leadsto \frac{\color{blue}{b\_2 \cdot -2}}{a} \]
    5. Applied rewrites98.2%

      \[\leadsto \frac{\color{blue}{b\_2 \cdot -2}}{a} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification86.9%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b\_2 \leq -3 \cdot 10^{-93}:\\ \;\;\;\;\frac{c}{b\_2} \cdot -0.5\\ \mathbf{elif}\;b\_2 \leq 10^{+126}:\\ \;\;\;\;\frac{\sqrt{b\_2 \cdot b\_2 - c \cdot a} + b\_2}{-a}\\ \mathbf{else}:\\ \;\;\;\;\frac{-2 \cdot b\_2}{a}\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 81.0% accurate, 0.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b\_2 \leq -3 \cdot 10^{-93}:\\ \;\;\;\;\frac{c}{b\_2} \cdot -0.5\\ \mathbf{elif}\;b\_2 \leq 5.2 \cdot 10^{-48}:\\ \;\;\;\;\frac{\sqrt{\left|\left(-a\right) \cdot c\right|} + b\_2}{-a}\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\frac{0.5}{b\_2}, c, \frac{b\_2}{a} \cdot -2\right)\\ \end{array} \end{array} \]
(FPCore (a b_2 c)
 :precision binary64
 (if (<= b_2 -3e-93)
   (* (/ c b_2) -0.5)
   (if (<= b_2 5.2e-48)
     (/ (+ (sqrt (fabs (* (- a) c))) b_2) (- a))
     (fma (/ 0.5 b_2) c (* (/ b_2 a) -2.0)))))
double code(double a, double b_2, double c) {
	double tmp;
	if (b_2 <= -3e-93) {
		tmp = (c / b_2) * -0.5;
	} else if (b_2 <= 5.2e-48) {
		tmp = (sqrt(fabs((-a * c))) + b_2) / -a;
	} else {
		tmp = fma((0.5 / b_2), c, ((b_2 / a) * -2.0));
	}
	return tmp;
}
function code(a, b_2, c)
	tmp = 0.0
	if (b_2 <= -3e-93)
		tmp = Float64(Float64(c / b_2) * -0.5);
	elseif (b_2 <= 5.2e-48)
		tmp = Float64(Float64(sqrt(abs(Float64(Float64(-a) * c))) + b_2) / Float64(-a));
	else
		tmp = fma(Float64(0.5 / b_2), c, Float64(Float64(b_2 / a) * -2.0));
	end
	return tmp
end
code[a_, b$95$2_, c_] := If[LessEqual[b$95$2, -3e-93], N[(N[(c / b$95$2), $MachinePrecision] * -0.5), $MachinePrecision], If[LessEqual[b$95$2, 5.2e-48], N[(N[(N[Sqrt[N[Abs[N[((-a) * c), $MachinePrecision]], $MachinePrecision]], $MachinePrecision] + b$95$2), $MachinePrecision] / (-a)), $MachinePrecision], N[(N[(0.5 / b$95$2), $MachinePrecision] * c + N[(N[(b$95$2 / a), $MachinePrecision] * -2.0), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b\_2 \leq -3 \cdot 10^{-93}:\\
\;\;\;\;\frac{c}{b\_2} \cdot -0.5\\

\mathbf{elif}\;b\_2 \leq 5.2 \cdot 10^{-48}:\\
\;\;\;\;\frac{\sqrt{\left|\left(-a\right) \cdot c\right|} + b\_2}{-a}\\

\mathbf{else}:\\
\;\;\;\;\mathsf{fma}\left(\frac{0.5}{b\_2}, c, \frac{b\_2}{a} \cdot -2\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if b_2 < -3.0000000000000001e-93

    1. Initial program 16.2%

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

      \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{c}{b\_2}} \]
    4. Step-by-step derivation
      1. lower-*.f64N/A

        \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{c}{b\_2}} \]
      2. lower-/.f6487.3

        \[\leadsto -0.5 \cdot \color{blue}{\frac{c}{b\_2}} \]
    5. Applied rewrites87.3%

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

    if -3.0000000000000001e-93 < b_2 < 5.19999999999999975e-48

    1. Initial program 75.9%

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

      \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{-1 \cdot \left(a \cdot c\right)}}}{a} \]
    4. Step-by-step derivation
      1. associate-*r*N/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{\left(-1 \cdot a\right) \cdot c}}}{a} \]
      2. lower-*.f64N/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{\left(-1 \cdot a\right) \cdot c}}}{a} \]
      3. mul-1-negN/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{\left(\mathsf{neg}\left(a\right)\right)} \cdot c}}{a} \]
      4. lower-neg.f6470.3

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{\left(-a\right)} \cdot c}}{a} \]
    5. Applied rewrites70.3%

      \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{\left(-a\right) \cdot c}}}{a} \]
    6. Step-by-step derivation
      1. rem-square-sqrtN/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{\sqrt{\left(\mathsf{neg}\left(a\right)\right) \cdot c} \cdot \sqrt{\left(\mathsf{neg}\left(a\right)\right) \cdot c}}}}{a} \]
      2. sqrt-unprodN/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{\sqrt{\left(\left(\mathsf{neg}\left(a\right)\right) \cdot c\right) \cdot \left(\left(\mathsf{neg}\left(a\right)\right) \cdot c\right)}}}}{a} \]
      3. rem-sqrt-squareN/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{\left|\left(\mathsf{neg}\left(a\right)\right) \cdot c\right|}}}{a} \]
      4. lower-fabs.f6470.9

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{\left|\left(-a\right) \cdot c\right|}}}{a} \]
    7. Applied rewrites70.9%

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

    if 5.19999999999999975e-48 < b_2

    1. Initial program 68.3%

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

      \[\leadsto \color{blue}{-2 \cdot \frac{b\_2}{a} + \frac{1}{2} \cdot \frac{c}{b\_2}} \]
    4. Step-by-step derivation
      1. +-commutativeN/A

        \[\leadsto \color{blue}{\frac{1}{2} \cdot \frac{c}{b\_2} + -2 \cdot \frac{b\_2}{a}} \]
      2. associate-*r/N/A

        \[\leadsto \color{blue}{\frac{\frac{1}{2} \cdot c}{b\_2}} + -2 \cdot \frac{b\_2}{a} \]
      3. associate-*l/N/A

        \[\leadsto \color{blue}{\frac{\frac{1}{2}}{b\_2} \cdot c} + -2 \cdot \frac{b\_2}{a} \]
      4. metadata-evalN/A

        \[\leadsto \frac{\color{blue}{\frac{1}{2} \cdot 1}}{b\_2} \cdot c + -2 \cdot \frac{b\_2}{a} \]
      5. associate-*r/N/A

        \[\leadsto \color{blue}{\left(\frac{1}{2} \cdot \frac{1}{b\_2}\right)} \cdot c + -2 \cdot \frac{b\_2}{a} \]
      6. lower-fma.f64N/A

        \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{1}{2} \cdot \frac{1}{b\_2}, c, -2 \cdot \frac{b\_2}{a}\right)} \]
      7. associate-*r/N/A

        \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{\frac{1}{2} \cdot 1}{b\_2}}, c, -2 \cdot \frac{b\_2}{a}\right) \]
      8. metadata-evalN/A

        \[\leadsto \mathsf{fma}\left(\frac{\color{blue}{\frac{1}{2}}}{b\_2}, c, -2 \cdot \frac{b\_2}{a}\right) \]
      9. lower-/.f64N/A

        \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{\frac{1}{2}}{b\_2}}, c, -2 \cdot \frac{b\_2}{a}\right) \]
      10. *-commutativeN/A

        \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{2}}{b\_2}, c, \color{blue}{\frac{b\_2}{a} \cdot -2}\right) \]
      11. lower-*.f64N/A

        \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{2}}{b\_2}, c, \color{blue}{\frac{b\_2}{a} \cdot -2}\right) \]
      12. lower-/.f6490.7

        \[\leadsto \mathsf{fma}\left(\frac{0.5}{b\_2}, c, \color{blue}{\frac{b\_2}{a}} \cdot -2\right) \]
    5. Applied rewrites90.7%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{0.5}{b\_2}, c, \frac{b\_2}{a} \cdot -2\right)} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification83.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b\_2 \leq -3 \cdot 10^{-93}:\\ \;\;\;\;\frac{c}{b\_2} \cdot -0.5\\ \mathbf{elif}\;b\_2 \leq 5.2 \cdot 10^{-48}:\\ \;\;\;\;\frac{\sqrt{\left|\left(-a\right) \cdot c\right|} + b\_2}{-a}\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\frac{0.5}{b\_2}, c, \frac{b\_2}{a} \cdot -2\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 80.9% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b\_2 \leq -3 \cdot 10^{-93}:\\ \;\;\;\;\frac{c}{b\_2} \cdot -0.5\\ \mathbf{elif}\;b\_2 \leq 5.2 \cdot 10^{-48}:\\ \;\;\;\;\frac{\sqrt{\left(-a\right) \cdot c} + b\_2}{-a}\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\frac{0.5}{b\_2}, c, \frac{b\_2}{a} \cdot -2\right)\\ \end{array} \end{array} \]
(FPCore (a b_2 c)
 :precision binary64
 (if (<= b_2 -3e-93)
   (* (/ c b_2) -0.5)
   (if (<= b_2 5.2e-48)
     (/ (+ (sqrt (* (- a) c)) b_2) (- a))
     (fma (/ 0.5 b_2) c (* (/ b_2 a) -2.0)))))
double code(double a, double b_2, double c) {
	double tmp;
	if (b_2 <= -3e-93) {
		tmp = (c / b_2) * -0.5;
	} else if (b_2 <= 5.2e-48) {
		tmp = (sqrt((-a * c)) + b_2) / -a;
	} else {
		tmp = fma((0.5 / b_2), c, ((b_2 / a) * -2.0));
	}
	return tmp;
}
function code(a, b_2, c)
	tmp = 0.0
	if (b_2 <= -3e-93)
		tmp = Float64(Float64(c / b_2) * -0.5);
	elseif (b_2 <= 5.2e-48)
		tmp = Float64(Float64(sqrt(Float64(Float64(-a) * c)) + b_2) / Float64(-a));
	else
		tmp = fma(Float64(0.5 / b_2), c, Float64(Float64(b_2 / a) * -2.0));
	end
	return tmp
end
code[a_, b$95$2_, c_] := If[LessEqual[b$95$2, -3e-93], N[(N[(c / b$95$2), $MachinePrecision] * -0.5), $MachinePrecision], If[LessEqual[b$95$2, 5.2e-48], N[(N[(N[Sqrt[N[((-a) * c), $MachinePrecision]], $MachinePrecision] + b$95$2), $MachinePrecision] / (-a)), $MachinePrecision], N[(N[(0.5 / b$95$2), $MachinePrecision] * c + N[(N[(b$95$2 / a), $MachinePrecision] * -2.0), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b\_2 \leq -3 \cdot 10^{-93}:\\
\;\;\;\;\frac{c}{b\_2} \cdot -0.5\\

\mathbf{elif}\;b\_2 \leq 5.2 \cdot 10^{-48}:\\
\;\;\;\;\frac{\sqrt{\left(-a\right) \cdot c} + b\_2}{-a}\\

\mathbf{else}:\\
\;\;\;\;\mathsf{fma}\left(\frac{0.5}{b\_2}, c, \frac{b\_2}{a} \cdot -2\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if b_2 < -3.0000000000000001e-93

    1. Initial program 16.2%

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

      \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{c}{b\_2}} \]
    4. Step-by-step derivation
      1. lower-*.f64N/A

        \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{c}{b\_2}} \]
      2. lower-/.f6487.3

        \[\leadsto -0.5 \cdot \color{blue}{\frac{c}{b\_2}} \]
    5. Applied rewrites87.3%

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

    if -3.0000000000000001e-93 < b_2 < 5.19999999999999975e-48

    1. Initial program 75.9%

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

      \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{-1 \cdot \left(a \cdot c\right)}}}{a} \]
    4. Step-by-step derivation
      1. associate-*r*N/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{\left(-1 \cdot a\right) \cdot c}}}{a} \]
      2. lower-*.f64N/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{\left(-1 \cdot a\right) \cdot c}}}{a} \]
      3. mul-1-negN/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{\left(\mathsf{neg}\left(a\right)\right)} \cdot c}}{a} \]
      4. lower-neg.f6470.3

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{\left(-a\right)} \cdot c}}{a} \]
    5. Applied rewrites70.3%

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

    if 5.19999999999999975e-48 < b_2

    1. Initial program 68.3%

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

      \[\leadsto \color{blue}{-2 \cdot \frac{b\_2}{a} + \frac{1}{2} \cdot \frac{c}{b\_2}} \]
    4. Step-by-step derivation
      1. +-commutativeN/A

        \[\leadsto \color{blue}{\frac{1}{2} \cdot \frac{c}{b\_2} + -2 \cdot \frac{b\_2}{a}} \]
      2. associate-*r/N/A

        \[\leadsto \color{blue}{\frac{\frac{1}{2} \cdot c}{b\_2}} + -2 \cdot \frac{b\_2}{a} \]
      3. associate-*l/N/A

        \[\leadsto \color{blue}{\frac{\frac{1}{2}}{b\_2} \cdot c} + -2 \cdot \frac{b\_2}{a} \]
      4. metadata-evalN/A

        \[\leadsto \frac{\color{blue}{\frac{1}{2} \cdot 1}}{b\_2} \cdot c + -2 \cdot \frac{b\_2}{a} \]
      5. associate-*r/N/A

        \[\leadsto \color{blue}{\left(\frac{1}{2} \cdot \frac{1}{b\_2}\right)} \cdot c + -2 \cdot \frac{b\_2}{a} \]
      6. lower-fma.f64N/A

        \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{1}{2} \cdot \frac{1}{b\_2}, c, -2 \cdot \frac{b\_2}{a}\right)} \]
      7. associate-*r/N/A

        \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{\frac{1}{2} \cdot 1}{b\_2}}, c, -2 \cdot \frac{b\_2}{a}\right) \]
      8. metadata-evalN/A

        \[\leadsto \mathsf{fma}\left(\frac{\color{blue}{\frac{1}{2}}}{b\_2}, c, -2 \cdot \frac{b\_2}{a}\right) \]
      9. lower-/.f64N/A

        \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{\frac{1}{2}}{b\_2}}, c, -2 \cdot \frac{b\_2}{a}\right) \]
      10. *-commutativeN/A

        \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{2}}{b\_2}, c, \color{blue}{\frac{b\_2}{a} \cdot -2}\right) \]
      11. lower-*.f64N/A

        \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{2}}{b\_2}, c, \color{blue}{\frac{b\_2}{a} \cdot -2}\right) \]
      12. lower-/.f6490.7

        \[\leadsto \mathsf{fma}\left(\frac{0.5}{b\_2}, c, \color{blue}{\frac{b\_2}{a}} \cdot -2\right) \]
    5. Applied rewrites90.7%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{0.5}{b\_2}, c, \frac{b\_2}{a} \cdot -2\right)} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification83.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b\_2 \leq -3 \cdot 10^{-93}:\\ \;\;\;\;\frac{c}{b\_2} \cdot -0.5\\ \mathbf{elif}\;b\_2 \leq 5.2 \cdot 10^{-48}:\\ \;\;\;\;\frac{\sqrt{\left(-a\right) \cdot c} + b\_2}{-a}\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\frac{0.5}{b\_2}, c, \frac{b\_2}{a} \cdot -2\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 67.6% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b\_2 \leq -5 \cdot 10^{-311}:\\ \;\;\;\;\frac{c}{b\_2} \cdot -0.5\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\frac{0.5}{b\_2}, c, \frac{b\_2}{a} \cdot -2\right)\\ \end{array} \end{array} \]
(FPCore (a b_2 c)
 :precision binary64
 (if (<= b_2 -5e-311)
   (* (/ c b_2) -0.5)
   (fma (/ 0.5 b_2) c (* (/ b_2 a) -2.0))))
double code(double a, double b_2, double c) {
	double tmp;
	if (b_2 <= -5e-311) {
		tmp = (c / b_2) * -0.5;
	} else {
		tmp = fma((0.5 / b_2), c, ((b_2 / a) * -2.0));
	}
	return tmp;
}
function code(a, b_2, c)
	tmp = 0.0
	if (b_2 <= -5e-311)
		tmp = Float64(Float64(c / b_2) * -0.5);
	else
		tmp = fma(Float64(0.5 / b_2), c, Float64(Float64(b_2 / a) * -2.0));
	end
	return tmp
end
code[a_, b$95$2_, c_] := If[LessEqual[b$95$2, -5e-311], N[(N[(c / b$95$2), $MachinePrecision] * -0.5), $MachinePrecision], N[(N[(0.5 / b$95$2), $MachinePrecision] * c + N[(N[(b$95$2 / a), $MachinePrecision] * -2.0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b\_2 \leq -5 \cdot 10^{-311}:\\
\;\;\;\;\frac{c}{b\_2} \cdot -0.5\\

\mathbf{else}:\\
\;\;\;\;\mathsf{fma}\left(\frac{0.5}{b\_2}, c, \frac{b\_2}{a} \cdot -2\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if b_2 < -5.00000000000023e-311

    1. Initial program 29.5%

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

      \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{c}{b\_2}} \]
    4. Step-by-step derivation
      1. lower-*.f64N/A

        \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{c}{b\_2}} \]
      2. lower-/.f6469.9

        \[\leadsto -0.5 \cdot \color{blue}{\frac{c}{b\_2}} \]
    5. Applied rewrites69.9%

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

    if -5.00000000000023e-311 < b_2

    1. Initial program 72.7%

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

      \[\leadsto \color{blue}{-2 \cdot \frac{b\_2}{a} + \frac{1}{2} \cdot \frac{c}{b\_2}} \]
    4. Step-by-step derivation
      1. +-commutativeN/A

        \[\leadsto \color{blue}{\frac{1}{2} \cdot \frac{c}{b\_2} + -2 \cdot \frac{b\_2}{a}} \]
      2. associate-*r/N/A

        \[\leadsto \color{blue}{\frac{\frac{1}{2} \cdot c}{b\_2}} + -2 \cdot \frac{b\_2}{a} \]
      3. associate-*l/N/A

        \[\leadsto \color{blue}{\frac{\frac{1}{2}}{b\_2} \cdot c} + -2 \cdot \frac{b\_2}{a} \]
      4. metadata-evalN/A

        \[\leadsto \frac{\color{blue}{\frac{1}{2} \cdot 1}}{b\_2} \cdot c + -2 \cdot \frac{b\_2}{a} \]
      5. associate-*r/N/A

        \[\leadsto \color{blue}{\left(\frac{1}{2} \cdot \frac{1}{b\_2}\right)} \cdot c + -2 \cdot \frac{b\_2}{a} \]
      6. lower-fma.f64N/A

        \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{1}{2} \cdot \frac{1}{b\_2}, c, -2 \cdot \frac{b\_2}{a}\right)} \]
      7. associate-*r/N/A

        \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{\frac{1}{2} \cdot 1}{b\_2}}, c, -2 \cdot \frac{b\_2}{a}\right) \]
      8. metadata-evalN/A

        \[\leadsto \mathsf{fma}\left(\frac{\color{blue}{\frac{1}{2}}}{b\_2}, c, -2 \cdot \frac{b\_2}{a}\right) \]
      9. lower-/.f64N/A

        \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{\frac{1}{2}}{b\_2}}, c, -2 \cdot \frac{b\_2}{a}\right) \]
      10. *-commutativeN/A

        \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{2}}{b\_2}, c, \color{blue}{\frac{b\_2}{a} \cdot -2}\right) \]
      11. lower-*.f64N/A

        \[\leadsto \mathsf{fma}\left(\frac{\frac{1}{2}}{b\_2}, c, \color{blue}{\frac{b\_2}{a} \cdot -2}\right) \]
      12. lower-/.f6465.7

        \[\leadsto \mathsf{fma}\left(\frac{0.5}{b\_2}, c, \color{blue}{\frac{b\_2}{a}} \cdot -2\right) \]
    5. Applied rewrites65.7%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{0.5}{b\_2}, c, \frac{b\_2}{a} \cdot -2\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification67.9%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b\_2 \leq -5 \cdot 10^{-311}:\\ \;\;\;\;\frac{c}{b\_2} \cdot -0.5\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\frac{0.5}{b\_2}, c, \frac{b\_2}{a} \cdot -2\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 5: 67.4% accurate, 1.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b\_2 \leq -5 \cdot 10^{-311}:\\ \;\;\;\;\frac{c}{b\_2} \cdot -0.5\\ \mathbf{else}:\\ \;\;\;\;\frac{-2 \cdot b\_2}{a}\\ \end{array} \end{array} \]
(FPCore (a b_2 c)
 :precision binary64
 (if (<= b_2 -5e-311) (* (/ c b_2) -0.5) (/ (* -2.0 b_2) a)))
double code(double a, double b_2, double c) {
	double tmp;
	if (b_2 <= -5e-311) {
		tmp = (c / b_2) * -0.5;
	} 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-311)) then
        tmp = (c / b_2) * (-0.5d0)
    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-311) {
		tmp = (c / b_2) * -0.5;
	} else {
		tmp = (-2.0 * b_2) / a;
	}
	return tmp;
}
def code(a, b_2, c):
	tmp = 0
	if b_2 <= -5e-311:
		tmp = (c / b_2) * -0.5
	else:
		tmp = (-2.0 * b_2) / a
	return tmp
function code(a, b_2, c)
	tmp = 0.0
	if (b_2 <= -5e-311)
		tmp = Float64(Float64(c / b_2) * -0.5);
	else
		tmp = Float64(Float64(-2.0 * b_2) / a);
	end
	return tmp
end
function tmp_2 = code(a, b_2, c)
	tmp = 0.0;
	if (b_2 <= -5e-311)
		tmp = (c / b_2) * -0.5;
	else
		tmp = (-2.0 * b_2) / a;
	end
	tmp_2 = tmp;
end
code[a_, b$95$2_, c_] := If[LessEqual[b$95$2, -5e-311], N[(N[(c / b$95$2), $MachinePrecision] * -0.5), $MachinePrecision], N[(N[(-2.0 * b$95$2), $MachinePrecision] / a), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b\_2 \leq -5 \cdot 10^{-311}:\\
\;\;\;\;\frac{c}{b\_2} \cdot -0.5\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if b_2 < -5.00000000000023e-311

    1. Initial program 29.5%

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

      \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{c}{b\_2}} \]
    4. Step-by-step derivation
      1. lower-*.f64N/A

        \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{c}{b\_2}} \]
      2. lower-/.f6469.9

        \[\leadsto -0.5 \cdot \color{blue}{\frac{c}{b\_2}} \]
    5. Applied rewrites69.9%

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

    if -5.00000000000023e-311 < b_2

    1. Initial program 72.7%

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

      \[\leadsto \frac{\color{blue}{-2 \cdot b\_2}}{a} \]
    4. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{\color{blue}{b\_2 \cdot -2}}{a} \]
      2. lower-*.f6465.0

        \[\leadsto \frac{\color{blue}{b\_2 \cdot -2}}{a} \]
    5. Applied rewrites65.0%

      \[\leadsto \frac{\color{blue}{b\_2 \cdot -2}}{a} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification67.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b\_2 \leq -5 \cdot 10^{-311}:\\ \;\;\;\;\frac{c}{b\_2} \cdot -0.5\\ \mathbf{else}:\\ \;\;\;\;\frac{-2 \cdot b\_2}{a}\\ \end{array} \]
  5. Add Preprocessing

Alternative 6: 47.8% accurate, 1.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b\_2 \leq -5 \cdot 10^{-311}:\\ \;\;\;\;\frac{c}{b\_2} \cdot -0.5\\ \mathbf{else}:\\ \;\;\;\;\frac{-b\_2}{a}\\ \end{array} \end{array} \]
(FPCore (a b_2 c)
 :precision binary64
 (if (<= b_2 -5e-311) (* (/ c b_2) -0.5) (/ (- b_2) a)))
double code(double a, double b_2, double c) {
	double tmp;
	if (b_2 <= -5e-311) {
		tmp = (c / b_2) * -0.5;
	} else {
		tmp = -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-311)) then
        tmp = (c / b_2) * (-0.5d0)
    else
        tmp = -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-311) {
		tmp = (c / b_2) * -0.5;
	} else {
		tmp = -b_2 / a;
	}
	return tmp;
}
def code(a, b_2, c):
	tmp = 0
	if b_2 <= -5e-311:
		tmp = (c / b_2) * -0.5
	else:
		tmp = -b_2 / a
	return tmp
function code(a, b_2, c)
	tmp = 0.0
	if (b_2 <= -5e-311)
		tmp = Float64(Float64(c / b_2) * -0.5);
	else
		tmp = Float64(Float64(-b_2) / a);
	end
	return tmp
end
function tmp_2 = code(a, b_2, c)
	tmp = 0.0;
	if (b_2 <= -5e-311)
		tmp = (c / b_2) * -0.5;
	else
		tmp = -b_2 / a;
	end
	tmp_2 = tmp;
end
code[a_, b$95$2_, c_] := If[LessEqual[b$95$2, -5e-311], N[(N[(c / b$95$2), $MachinePrecision] * -0.5), $MachinePrecision], N[((-b$95$2) / a), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b\_2 \leq -5 \cdot 10^{-311}:\\
\;\;\;\;\frac{c}{b\_2} \cdot -0.5\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if b_2 < -5.00000000000023e-311

    1. Initial program 29.5%

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

      \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{c}{b\_2}} \]
    4. Step-by-step derivation
      1. lower-*.f64N/A

        \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{c}{b\_2}} \]
      2. lower-/.f6469.9

        \[\leadsto -0.5 \cdot \color{blue}{\frac{c}{b\_2}} \]
    5. Applied rewrites69.9%

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

    if -5.00000000000023e-311 < b_2

    1. Initial program 72.7%

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

      \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{-1 \cdot \left(a \cdot c\right)}}}{a} \]
    4. Step-by-step derivation
      1. associate-*r*N/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{\left(-1 \cdot a\right) \cdot c}}}{a} \]
      2. lower-*.f64N/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{\left(-1 \cdot a\right) \cdot c}}}{a} \]
      3. mul-1-negN/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{\left(\mathsf{neg}\left(a\right)\right)} \cdot c}}{a} \]
      4. lower-neg.f6446.4

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{\left(-a\right)} \cdot c}}{a} \]
    5. Applied rewrites46.4%

      \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{\left(-a\right) \cdot c}}}{a} \]
    6. Step-by-step derivation
      1. rem-square-sqrtN/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{\sqrt{\left(\mathsf{neg}\left(a\right)\right) \cdot c} \cdot \sqrt{\left(\mathsf{neg}\left(a\right)\right) \cdot c}}}}{a} \]
      2. sqrt-unprodN/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{\sqrt{\left(\left(\mathsf{neg}\left(a\right)\right) \cdot c\right) \cdot \left(\left(\mathsf{neg}\left(a\right)\right) \cdot c\right)}}}}{a} \]
      3. rem-sqrt-squareN/A

        \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{\left|\left(\mathsf{neg}\left(a\right)\right) \cdot c\right|}}}{a} \]
      4. lower-fabs.f6456.6

        \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{\left|\left(-a\right) \cdot c\right|}}}{a} \]
    7. Applied rewrites56.6%

      \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{\left|\left(-a\right) \cdot c\right|}}}{a} \]
    8. Taylor expanded in b_2 around inf

      \[\leadsto \frac{\color{blue}{-1 \cdot b\_2}}{a} \]
    9. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \frac{\color{blue}{\mathsf{neg}\left(b\_2\right)}}{a} \]
      2. lower-neg.f6429.9

        \[\leadsto \frac{\color{blue}{-b\_2}}{a} \]
    10. Applied rewrites29.9%

      \[\leadsto \frac{\color{blue}{-b\_2}}{a} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification51.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b\_2 \leq -5 \cdot 10^{-311}:\\ \;\;\;\;\frac{c}{b\_2} \cdot -0.5\\ \mathbf{else}:\\ \;\;\;\;\frac{-b\_2}{a}\\ \end{array} \]
  5. Add Preprocessing

Alternative 7: 15.0% accurate, 2.9× speedup?

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

\\
\frac{-b\_2}{a}
\end{array}
Derivation
  1. Initial program 49.4%

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

    \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{-1 \cdot \left(a \cdot c\right)}}}{a} \]
  4. Step-by-step derivation
    1. associate-*r*N/A

      \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{\left(-1 \cdot a\right) \cdot c}}}{a} \]
    2. lower-*.f64N/A

      \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{\left(-1 \cdot a\right) \cdot c}}}{a} \]
    3. mul-1-negN/A

      \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{\left(\mathsf{neg}\left(a\right)\right)} \cdot c}}{a} \]
    4. lower-neg.f6434.6

      \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{\left(-a\right)} \cdot c}}{a} \]
  5. Applied rewrites34.6%

    \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{\left(-a\right) \cdot c}}}{a} \]
  6. Step-by-step derivation
    1. rem-square-sqrtN/A

      \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{\sqrt{\left(\mathsf{neg}\left(a\right)\right) \cdot c} \cdot \sqrt{\left(\mathsf{neg}\left(a\right)\right) \cdot c}}}}{a} \]
    2. sqrt-unprodN/A

      \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{\sqrt{\left(\left(\mathsf{neg}\left(a\right)\right) \cdot c\right) \cdot \left(\left(\mathsf{neg}\left(a\right)\right) \cdot c\right)}}}}{a} \]
    3. rem-sqrt-squareN/A

      \[\leadsto \frac{\left(\mathsf{neg}\left(b\_2\right)\right) - \sqrt{\color{blue}{\left|\left(\mathsf{neg}\left(a\right)\right) \cdot c\right|}}}{a} \]
    4. lower-fabs.f6440.0

      \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{\left|\left(-a\right) \cdot c\right|}}}{a} \]
  7. Applied rewrites40.0%

    \[\leadsto \frac{\left(-b\_2\right) - \sqrt{\color{blue}{\left|\left(-a\right) \cdot c\right|}}}{a} \]
  8. Taylor expanded in b_2 around inf

    \[\leadsto \frac{\color{blue}{-1 \cdot b\_2}}{a} \]
  9. Step-by-step derivation
    1. mul-1-negN/A

      \[\leadsto \frac{\color{blue}{\mathsf{neg}\left(b\_2\right)}}{a} \]
    2. lower-neg.f6415.4

      \[\leadsto \frac{\color{blue}{-b\_2}}{a} \]
  10. Applied rewrites15.4%

    \[\leadsto \frac{\color{blue}{-b\_2}}{a} \]
  11. Add Preprocessing

Developer Target 1: 99.7% accurate, 0.2× 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 2024235 
(FPCore (a b_2 c)
  :name "quad2m (problem 3.2.1, negative)"
  :precision binary64
  :herbie-expected 10

  :alt
  (! :herbie-platform default (let ((sqtD (let ((x (* (sqrt (fabs a)) (sqrt (fabs c))))) (if (== (copysign a c) a) (* (sqrt (- (fabs b_2) x)) (sqrt (+ (fabs b_2) x))) (hypot b_2 x))))) (if (< b_2 0) (/ c (- sqtD b_2)) (/ (+ b_2 sqtD) (- a)))))

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