Quadratic roots, wide range

Percentage Accurate: 17.9% → 99.9%
Time: 13.8s
Alternatives: 6
Speedup: 3.3×

Specification

?
\[\left(\left(4.930380657631324 \cdot 10^{-32} < a \land a < 2.028240960365167 \cdot 10^{+31}\right) \land \left(4.930380657631324 \cdot 10^{-32} < b \land b < 2.028240960365167 \cdot 10^{+31}\right)\right) \land \left(4.930380657631324 \cdot 10^{-32} < c \land c < 2.028240960365167 \cdot 10^{+31}\right)\]
\[\begin{array}{l} \\ \frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (/ (+ (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))) (* 2.0 a)))
double code(double a, double b, double c) {
	return (-b + sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a);
}
real(8) function code(a, b, c)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: c
    code = (-b + sqrt(((b * b) - ((4.0d0 * a) * c)))) / (2.0d0 * a)
end function
public static double code(double a, double b, double c) {
	return (-b + Math.sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a);
}
def code(a, b, c):
	return (-b + math.sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a)
function code(a, b, c)
	return Float64(Float64(Float64(-b) + sqrt(Float64(Float64(b * b) - Float64(Float64(4.0 * a) * c)))) / Float64(2.0 * a))
end
function tmp = code(a, b, c)
	tmp = (-b + sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a);
end
code[a_, b_, c_] := N[(N[((-b) + N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(4.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

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

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

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

Accuracy vs Speed?

Herbie found 6 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: 17.9% accurate, 1.0× speedup?

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

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

Alternative 1: 99.9% accurate, 0.7× speedup?

\[\begin{array}{l} \\ \frac{-2 \cdot c}{b + \sqrt{b \cdot \left(b \cdot \mathsf{fma}\left(a \cdot -4, \frac{c}{b \cdot b}, 1\right)\right)}} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (/ (* -2.0 c) (+ b (sqrt (* b (* b (fma (* a -4.0) (/ c (* b b)) 1.0)))))))
double code(double a, double b, double c) {
	return (-2.0 * c) / (b + sqrt((b * (b * fma((a * -4.0), (c / (b * b)), 1.0)))));
}
function code(a, b, c)
	return Float64(Float64(-2.0 * c) / Float64(b + sqrt(Float64(b * Float64(b * fma(Float64(a * -4.0), Float64(c / Float64(b * b)), 1.0))))))
end
code[a_, b_, c_] := N[(N[(-2.0 * c), $MachinePrecision] / N[(b + N[Sqrt[N[(b * N[(b * N[(N[(a * -4.0), $MachinePrecision] * N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{-2 \cdot c}{b + \sqrt{b \cdot \left(b \cdot \mathsf{fma}\left(a \cdot -4, \frac{c}{b \cdot b}, 1\right)\right)}}
\end{array}
Derivation
  1. Initial program 16.6%

    \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
  2. Add Preprocessing
  3. Applied egg-rr16.7%

    \[\leadsto \color{blue}{\frac{-0.5}{a} \cdot \left(b - \sqrt{\mathsf{fma}\left(b, b, c \cdot \left(a \cdot -4\right)\right)}\right)} \]
  4. Step-by-step derivation
    1. flip--N/A

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

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

      \[\leadsto \color{blue}{\frac{\frac{\frac{-1}{2}}{a} \cdot \left(b \cdot b - \sqrt{b \cdot b + c \cdot \left(a \cdot -4\right)} \cdot \sqrt{b \cdot b + c \cdot \left(a \cdot -4\right)}\right)}{b + \sqrt{b \cdot b + c \cdot \left(a \cdot -4\right)}}} \]
  5. Applied egg-rr17.1%

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

    \[\leadsto \frac{\color{blue}{-2 \cdot c}}{b + \sqrt{\mathsf{fma}\left(c, a \cdot -4, \mathsf{fma}\left(b, b, 0\right)\right)}} \]
  7. Step-by-step derivation
    1. *-lowering-*.f6499.9

      \[\leadsto \frac{\color{blue}{-2 \cdot c}}{b + \sqrt{\mathsf{fma}\left(c, a \cdot -4, \mathsf{fma}\left(b, b, 0\right)\right)}} \]
  8. Simplified99.9%

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

    \[\leadsto \frac{-2 \cdot c}{b + \sqrt{\color{blue}{{b}^{2} \cdot \left(1 + -4 \cdot \frac{a \cdot c}{{b}^{2}}\right)}}} \]
  10. Step-by-step derivation
    1. unpow2N/A

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

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

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

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

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

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

      \[\leadsto \frac{-2 \cdot c}{b + \sqrt{b \cdot \left(b \cdot \left(\color{blue}{\left(-4 \cdot a\right) \cdot \frac{c}{{b}^{2}}} + 1\right)\right)}} \]
    8. accelerator-lowering-fma.f64N/A

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

      \[\leadsto \frac{-2 \cdot c}{b + \sqrt{b \cdot \left(b \cdot \mathsf{fma}\left(\color{blue}{a \cdot -4}, \frac{c}{{b}^{2}}, 1\right)\right)}} \]
    10. *-lowering-*.f64N/A

      \[\leadsto \frac{-2 \cdot c}{b + \sqrt{b \cdot \left(b \cdot \mathsf{fma}\left(\color{blue}{a \cdot -4}, \frac{c}{{b}^{2}}, 1\right)\right)}} \]
    11. /-lowering-/.f64N/A

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

      \[\leadsto \frac{-2 \cdot c}{b + \sqrt{b \cdot \left(b \cdot \mathsf{fma}\left(a \cdot -4, \frac{c}{\color{blue}{b \cdot b}}, 1\right)\right)}} \]
    13. *-lowering-*.f6499.9

      \[\leadsto \frac{-2 \cdot c}{b + \sqrt{b \cdot \left(b \cdot \mathsf{fma}\left(a \cdot -4, \frac{c}{\color{blue}{b \cdot b}}, 1\right)\right)}} \]
  11. Simplified99.9%

    \[\leadsto \frac{-2 \cdot c}{b + \sqrt{\color{blue}{b \cdot \left(b \cdot \mathsf{fma}\left(a \cdot -4, \frac{c}{b \cdot b}, 1\right)\right)}}} \]
  12. Add Preprocessing

Alternative 2: 99.9% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \frac{-2 \cdot c}{b + \sqrt{\mathsf{fma}\left(b, b, c \cdot \left(a \cdot -4\right)\right)}} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (/ (* -2.0 c) (+ b (sqrt (fma b b (* c (* a -4.0)))))))
double code(double a, double b, double c) {
	return (-2.0 * c) / (b + sqrt(fma(b, b, (c * (a * -4.0)))));
}
function code(a, b, c)
	return Float64(Float64(-2.0 * c) / Float64(b + sqrt(fma(b, b, Float64(c * Float64(a * -4.0))))))
end
code[a_, b_, c_] := N[(N[(-2.0 * c), $MachinePrecision] / N[(b + N[Sqrt[N[(b * b + N[(c * N[(a * -4.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{-2 \cdot c}{b + \sqrt{\mathsf{fma}\left(b, b, c \cdot \left(a \cdot -4\right)\right)}}
\end{array}
Derivation
  1. Initial program 16.6%

    \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
  2. Add Preprocessing
  3. Applied egg-rr16.7%

    \[\leadsto \color{blue}{\frac{-0.5}{a} \cdot \left(b - \sqrt{\mathsf{fma}\left(b, b, c \cdot \left(a \cdot -4\right)\right)}\right)} \]
  4. Step-by-step derivation
    1. flip--N/A

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

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

      \[\leadsto \color{blue}{\frac{\frac{\frac{-1}{2}}{a} \cdot \left(b \cdot b - \sqrt{b \cdot b + c \cdot \left(a \cdot -4\right)} \cdot \sqrt{b \cdot b + c \cdot \left(a \cdot -4\right)}\right)}{b + \sqrt{b \cdot b + c \cdot \left(a \cdot -4\right)}}} \]
  5. Applied egg-rr17.1%

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

    \[\leadsto \frac{\color{blue}{-2 \cdot c}}{b + \sqrt{\mathsf{fma}\left(c, a \cdot -4, \mathsf{fma}\left(b, b, 0\right)\right)}} \]
  7. Step-by-step derivation
    1. *-lowering-*.f6499.9

      \[\leadsto \frac{\color{blue}{-2 \cdot c}}{b + \sqrt{\mathsf{fma}\left(c, a \cdot -4, \mathsf{fma}\left(b, b, 0\right)\right)}} \]
  8. Simplified99.9%

    \[\leadsto \frac{\color{blue}{-2 \cdot c}}{b + \sqrt{\mathsf{fma}\left(c, a \cdot -4, \mathsf{fma}\left(b, b, 0\right)\right)}} \]
  9. Step-by-step derivation
    1. +-rgt-identityN/A

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

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

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

      \[\leadsto \frac{-2 \cdot c}{b + \sqrt{\mathsf{fma}\left(b, b, \color{blue}{c \cdot \left(a \cdot -4\right)}\right)}} \]
    5. *-lowering-*.f6499.9

      \[\leadsto \frac{-2 \cdot c}{b + \sqrt{\mathsf{fma}\left(b, b, c \cdot \color{blue}{\left(a \cdot -4\right)}\right)}} \]
  10. Applied egg-rr99.9%

    \[\leadsto \frac{-2 \cdot c}{b + \sqrt{\color{blue}{\mathsf{fma}\left(b, b, c \cdot \left(a \cdot -4\right)\right)}}} \]
  11. Add Preprocessing

Alternative 3: 95.4% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \frac{-2 \cdot c}{\mathsf{fma}\left(b, 2, \frac{c \cdot \left(-2 \cdot a\right)}{b}\right)} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (/ (* -2.0 c) (fma b 2.0 (/ (* c (* -2.0 a)) b))))
double code(double a, double b, double c) {
	return (-2.0 * c) / fma(b, 2.0, ((c * (-2.0 * a)) / b));
}
function code(a, b, c)
	return Float64(Float64(-2.0 * c) / fma(b, 2.0, Float64(Float64(c * Float64(-2.0 * a)) / b)))
end
code[a_, b_, c_] := N[(N[(-2.0 * c), $MachinePrecision] / N[(b * 2.0 + N[(N[(c * N[(-2.0 * a), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{-2 \cdot c}{\mathsf{fma}\left(b, 2, \frac{c \cdot \left(-2 \cdot a\right)}{b}\right)}
\end{array}
Derivation
  1. Initial program 16.6%

    \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
  2. Add Preprocessing
  3. Applied egg-rr16.7%

    \[\leadsto \color{blue}{\frac{-0.5}{a} \cdot \left(b - \sqrt{\mathsf{fma}\left(b, b, c \cdot \left(a \cdot -4\right)\right)}\right)} \]
  4. Step-by-step derivation
    1. flip--N/A

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

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

      \[\leadsto \color{blue}{\frac{\frac{\frac{-1}{2}}{a} \cdot \left(b \cdot b - \sqrt{b \cdot b + c \cdot \left(a \cdot -4\right)} \cdot \sqrt{b \cdot b + c \cdot \left(a \cdot -4\right)}\right)}{b + \sqrt{b \cdot b + c \cdot \left(a \cdot -4\right)}}} \]
  5. Applied egg-rr17.1%

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

    \[\leadsto \frac{\color{blue}{-2 \cdot c}}{b + \sqrt{\mathsf{fma}\left(c, a \cdot -4, \mathsf{fma}\left(b, b, 0\right)\right)}} \]
  7. Step-by-step derivation
    1. *-lowering-*.f6499.9

      \[\leadsto \frac{\color{blue}{-2 \cdot c}}{b + \sqrt{\mathsf{fma}\left(c, a \cdot -4, \mathsf{fma}\left(b, b, 0\right)\right)}} \]
  8. Simplified99.9%

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

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

      \[\leadsto \frac{-2 \cdot c}{\color{blue}{2 \cdot b + -2 \cdot \frac{a \cdot c}{b}}} \]
    2. *-commutativeN/A

      \[\leadsto \frac{-2 \cdot c}{\color{blue}{b \cdot 2} + -2 \cdot \frac{a \cdot c}{b}} \]
    3. *-commutativeN/A

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

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

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

      \[\leadsto \frac{-2 \cdot c}{b \cdot 2 + a \cdot \color{blue}{\left(-2 \cdot \frac{c}{b}\right)}} \]
    7. accelerator-lowering-fma.f64N/A

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

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

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

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

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

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

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

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

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

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

      \[\leadsto \frac{-2 \cdot c}{\mathsf{fma}\left(b, 2, \frac{\color{blue}{c \cdot \left(a \cdot -2\right)}}{b}\right)} \]
    18. *-lowering-*.f6496.0

      \[\leadsto \frac{-2 \cdot c}{\mathsf{fma}\left(b, 2, \frac{c \cdot \color{blue}{\left(a \cdot -2\right)}}{b}\right)} \]
  11. Simplified96.0%

    \[\leadsto \frac{-2 \cdot c}{\color{blue}{\mathsf{fma}\left(b, 2, \frac{c \cdot \left(a \cdot -2\right)}{b}\right)}} \]
  12. Final simplification96.0%

    \[\leadsto \frac{-2 \cdot c}{\mathsf{fma}\left(b, 2, \frac{c \cdot \left(-2 \cdot a\right)}{b}\right)} \]
  13. Add Preprocessing

Alternative 4: 95.4% accurate, 1.2× speedup?

\[\begin{array}{l} \\ \frac{-2 \cdot c}{b + \mathsf{fma}\left(\frac{c}{b}, -2 \cdot a, b\right)} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (/ (* -2.0 c) (+ b (fma (/ c b) (* -2.0 a) b))))
double code(double a, double b, double c) {
	return (-2.0 * c) / (b + fma((c / b), (-2.0 * a), b));
}
function code(a, b, c)
	return Float64(Float64(-2.0 * c) / Float64(b + fma(Float64(c / b), Float64(-2.0 * a), b)))
end
code[a_, b_, c_] := N[(N[(-2.0 * c), $MachinePrecision] / N[(b + N[(N[(c / b), $MachinePrecision] * N[(-2.0 * a), $MachinePrecision] + b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{-2 \cdot c}{b + \mathsf{fma}\left(\frac{c}{b}, -2 \cdot a, b\right)}
\end{array}
Derivation
  1. Initial program 16.6%

    \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
  2. Add Preprocessing
  3. Applied egg-rr16.7%

    \[\leadsto \color{blue}{\frac{-0.5}{a} \cdot \left(b - \sqrt{\mathsf{fma}\left(b, b, c \cdot \left(a \cdot -4\right)\right)}\right)} \]
  4. Step-by-step derivation
    1. flip--N/A

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

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

      \[\leadsto \color{blue}{\frac{\frac{\frac{-1}{2}}{a} \cdot \left(b \cdot b - \sqrt{b \cdot b + c \cdot \left(a \cdot -4\right)} \cdot \sqrt{b \cdot b + c \cdot \left(a \cdot -4\right)}\right)}{b + \sqrt{b \cdot b + c \cdot \left(a \cdot -4\right)}}} \]
  5. Applied egg-rr17.1%

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

    \[\leadsto \frac{\color{blue}{-2 \cdot c}}{b + \sqrt{\mathsf{fma}\left(c, a \cdot -4, \mathsf{fma}\left(b, b, 0\right)\right)}} \]
  7. Step-by-step derivation
    1. *-lowering-*.f6499.9

      \[\leadsto \frac{\color{blue}{-2 \cdot c}}{b + \sqrt{\mathsf{fma}\left(c, a \cdot -4, \mathsf{fma}\left(b, b, 0\right)\right)}} \]
  8. Simplified99.9%

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

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

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

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

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

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

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

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

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

      \[\leadsto \frac{-2 \cdot c}{b + \left(\color{blue}{\frac{c}{b} \cdot \left(-2 \cdot a\right)} + b\right)} \]
    9. accelerator-lowering-fma.f64N/A

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

      \[\leadsto \frac{-2 \cdot c}{b + \mathsf{fma}\left(\color{blue}{\frac{c}{b}}, -2 \cdot a, b\right)} \]
    11. *-lowering-*.f6496.0

      \[\leadsto \frac{-2 \cdot c}{b + \mathsf{fma}\left(\frac{c}{b}, \color{blue}{-2 \cdot a}, b\right)} \]
  11. Simplified96.0%

    \[\leadsto \frac{-2 \cdot c}{b + \color{blue}{\mathsf{fma}\left(\frac{c}{b}, -2 \cdot a, b\right)}} \]
  12. Add Preprocessing

Alternative 5: 95.3% accurate, 1.2× speedup?

\[\begin{array}{l} \\ \frac{\mathsf{fma}\left(c \cdot c, \frac{a}{b \cdot b}, c\right)}{0 - b} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (/ (fma (* c c) (/ a (* b b)) c) (- 0.0 b)))
double code(double a, double b, double c) {
	return fma((c * c), (a / (b * b)), c) / (0.0 - b);
}
function code(a, b, c)
	return Float64(fma(Float64(c * c), Float64(a / Float64(b * b)), c) / Float64(0.0 - b))
end
code[a_, b_, c_] := N[(N[(N[(c * c), $MachinePrecision] * N[(a / N[(b * b), $MachinePrecision]), $MachinePrecision] + c), $MachinePrecision] / N[(0.0 - b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\mathsf{fma}\left(c \cdot c, \frac{a}{b \cdot b}, c\right)}{0 - b}
\end{array}
Derivation
  1. Initial program 16.6%

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

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

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

      \[\leadsto \color{blue}{-1 \cdot \frac{c + \frac{a \cdot {c}^{2}}{{b}^{2}}}{b}} \]
    3. mul-1-negN/A

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

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

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

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

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

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

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

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

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

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

      \[\leadsto \mathsf{neg}\left(\frac{\mathsf{fma}\left(c \cdot c, \frac{a}{\color{blue}{b \cdot b}}, c\right)}{b}\right) \]
    14. *-lowering-*.f6495.9

      \[\leadsto -\frac{\mathsf{fma}\left(c \cdot c, \frac{a}{\color{blue}{b \cdot b}}, c\right)}{b} \]
  5. Simplified95.9%

    \[\leadsto \color{blue}{-\frac{\mathsf{fma}\left(c \cdot c, \frac{a}{b \cdot b}, c\right)}{b}} \]
  6. Final simplification95.9%

    \[\leadsto \frac{\mathsf{fma}\left(c \cdot c, \frac{a}{b \cdot b}, c\right)}{0 - b} \]
  7. Add Preprocessing

Alternative 6: 90.4% accurate, 3.3× speedup?

\[\begin{array}{l} \\ \frac{0 - c}{b} \end{array} \]
(FPCore (a b c) :precision binary64 (/ (- 0.0 c) b))
double code(double a, double b, double c) {
	return (0.0 - 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 = (0.0d0 - c) / b
end function
public static double code(double a, double b, double c) {
	return (0.0 - c) / b;
}
def code(a, b, c):
	return (0.0 - c) / b
function code(a, b, c)
	return Float64(Float64(0.0 - c) / b)
end
function tmp = code(a, b, c)
	tmp = (0.0 - c) / b;
end
code[a_, b_, c_] := N[(N[(0.0 - c), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}

\\
\frac{0 - c}{b}
\end{array}
Derivation
  1. Initial program 16.6%

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

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

      \[\leadsto \color{blue}{\mathsf{neg}\left(\frac{c}{b}\right)} \]
    2. neg-sub0N/A

      \[\leadsto \color{blue}{0 - \frac{c}{b}} \]
    3. --lowering--.f64N/A

      \[\leadsto \color{blue}{0 - \frac{c}{b}} \]
    4. /-lowering-/.f6491.1

      \[\leadsto 0 - \color{blue}{\frac{c}{b}} \]
  5. Simplified91.1%

    \[\leadsto \color{blue}{0 - \frac{c}{b}} \]
  6. Step-by-step derivation
    1. sub0-negN/A

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

      \[\leadsto \color{blue}{\mathsf{neg}\left(\frac{c}{b}\right)} \]
    3. /-lowering-/.f6491.1

      \[\leadsto -\color{blue}{\frac{c}{b}} \]
  7. Applied egg-rr91.1%

    \[\leadsto \color{blue}{-\frac{c}{b}} \]
  8. Final simplification91.1%

    \[\leadsto \frac{0 - c}{b} \]
  9. Add Preprocessing

Reproduce

?
herbie shell --seed 2024198 
(FPCore (a b c)
  :name "Quadratic roots, wide range"
  :precision binary64
  :pre (and (and (and (< 4.930380657631324e-32 a) (< a 2.028240960365167e+31)) (and (< 4.930380657631324e-32 b) (< b 2.028240960365167e+31))) (and (< 4.930380657631324e-32 c) (< c 2.028240960365167e+31)))
  (/ (+ (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))) (* 2.0 a)))