Quadratic roots, medium range

Percentage Accurate: 31.1% → 95.8%
Time: 14.1s
Alternatives: 6
Speedup: 3.6×

Specification

?
\[\left(\left(1.1102230246251565 \cdot 10^{-16} < a \land a < 9007199254740992\right) \land \left(1.1102230246251565 \cdot 10^{-16} < b \land b < 9007199254740992\right)\right) \land \left(1.1102230246251565 \cdot 10^{-16} < c \land c < 9007199254740992\right)\]
\[\begin{array}{l} \\ \frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \end{array} \]
(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: 31.1% 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: 95.8% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := b \cdot \left(b \cdot \left(b \cdot b\right)\right)\\ t_1 := c \cdot \left(c \cdot c\right)\\ \frac{\left(\mathsf{fma}\left(-5 \cdot \left(c \cdot t\_1\right), \frac{a \cdot \left(a \cdot a\right)}{\left(b \cdot b\right) \cdot t\_0}, \frac{\left(a \cdot a\right) \cdot \left(t\_1 \cdot -2\right)}{t\_0}\right) - \frac{c \cdot \left(c \cdot a\right)}{b \cdot b}\right) - c}{b} \end{array} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (let* ((t_0 (* b (* b (* b b)))) (t_1 (* c (* c c))))
   (/
    (-
     (-
      (fma
       (* -5.0 (* c t_1))
       (/ (* a (* a a)) (* (* b b) t_0))
       (/ (* (* a a) (* t_1 -2.0)) t_0))
      (/ (* c (* c a)) (* b b)))
     c)
    b)))
double code(double a, double b, double c) {
	double t_0 = b * (b * (b * b));
	double t_1 = c * (c * c);
	return ((fma((-5.0 * (c * t_1)), ((a * (a * a)) / ((b * b) * t_0)), (((a * a) * (t_1 * -2.0)) / t_0)) - ((c * (c * a)) / (b * b))) - c) / b;
}
function code(a, b, c)
	t_0 = Float64(b * Float64(b * Float64(b * b)))
	t_1 = Float64(c * Float64(c * c))
	return Float64(Float64(Float64(fma(Float64(-5.0 * Float64(c * t_1)), Float64(Float64(a * Float64(a * a)) / Float64(Float64(b * b) * t_0)), Float64(Float64(Float64(a * a) * Float64(t_1 * -2.0)) / t_0)) - Float64(Float64(c * Float64(c * a)) / Float64(b * b))) - c) / b)
end
code[a_, b_, c_] := Block[{t$95$0 = N[(b * N[(b * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(c * N[(c * c), $MachinePrecision]), $MachinePrecision]}, N[(N[(N[(N[(N[(-5.0 * N[(c * t$95$1), $MachinePrecision]), $MachinePrecision] * N[(N[(a * N[(a * a), $MachinePrecision]), $MachinePrecision] / N[(N[(b * b), $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision] + N[(N[(N[(a * a), $MachinePrecision] * N[(t$95$1 * -2.0), $MachinePrecision]), $MachinePrecision] / t$95$0), $MachinePrecision]), $MachinePrecision] - N[(N[(c * N[(c * a), $MachinePrecision]), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - c), $MachinePrecision] / b), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := b \cdot \left(b \cdot \left(b \cdot b\right)\right)\\
t_1 := c \cdot \left(c \cdot c\right)\\
\frac{\left(\mathsf{fma}\left(-5 \cdot \left(c \cdot t\_1\right), \frac{a \cdot \left(a \cdot a\right)}{\left(b \cdot b\right) \cdot t\_0}, \frac{\left(a \cdot a\right) \cdot \left(t\_1 \cdot -2\right)}{t\_0}\right) - \frac{c \cdot \left(c \cdot a\right)}{b \cdot b}\right) - c}{b}
\end{array}
\end{array}
Derivation
  1. Initial program 31.5%

    \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
  2. Add Preprocessing
  3. Taylor expanded in a around 0

    \[\leadsto \color{blue}{-1 \cdot \frac{c}{b} + a \cdot \left(-1 \cdot \frac{{c}^{2}}{{b}^{3}} + a \cdot \left(-2 \cdot \frac{{c}^{3}}{{b}^{5}} + \frac{-1}{4} \cdot \frac{a \cdot \left(4 \cdot \frac{{c}^{4}}{{b}^{6}} + 16 \cdot \frac{{c}^{4}}{{b}^{6}}\right)}{b}\right)\right)} \]
  4. Simplified94.9%

    \[\leadsto \color{blue}{\left(-\frac{\mathsf{fma}\left(c \cdot c, \frac{a}{b \cdot b}, c\right)}{b}\right) + \left(a \cdot a\right) \cdot \mathsf{fma}\left(\frac{{c}^{4} \cdot 20}{{b}^{6}} \cdot \frac{a}{b}, -0.25, \frac{\left(c \cdot \left(c \cdot c\right)\right) \cdot -2}{{b}^{5}}\right)} \]
  5. Taylor expanded in b around inf

    \[\leadsto \color{blue}{\frac{\left(-5 \cdot \frac{{a}^{3} \cdot {c}^{4}}{{b}^{6}} + -2 \cdot \frac{{a}^{2} \cdot {c}^{3}}{{b}^{4}}\right) - \left(c + \frac{a \cdot {c}^{2}}{{b}^{2}}\right)}{b}} \]
  6. Step-by-step derivation
    1. /-lowering-/.f64N/A

      \[\leadsto \color{blue}{\frac{\left(-5 \cdot \frac{{a}^{3} \cdot {c}^{4}}{{b}^{6}} + -2 \cdot \frac{{a}^{2} \cdot {c}^{3}}{{b}^{4}}\right) - \left(c + \frac{a \cdot {c}^{2}}{{b}^{2}}\right)}{b}} \]
  7. Simplified94.9%

    \[\leadsto \color{blue}{\frac{\mathsf{fma}\left(-5, \frac{{c}^{4} \cdot \left(a \cdot \left(a \cdot a\right)\right)}{{b}^{6}}, \frac{\left(-2 \cdot \left(a \cdot a\right)\right) \cdot \left(c \cdot \left(c \cdot c\right)\right)}{{b}^{4}}\right) - \mathsf{fma}\left(a, \frac{c \cdot c}{b \cdot b}, c\right)}{b}} \]
  8. Applied egg-rr95.0%

    \[\leadsto \frac{\color{blue}{\left(\mathsf{fma}\left(-5 \cdot \left(c \cdot \left(c \cdot \left(c \cdot c\right)\right)\right), \frac{a \cdot \left(a \cdot a\right)}{\left(b \cdot \left(b \cdot \left(b \cdot b\right)\right)\right) \cdot \left(b \cdot b\right)}, \frac{\left(a \cdot a\right) \cdot \left(-2 \cdot \left(c \cdot \left(c \cdot c\right)\right)\right)}{b \cdot \left(b \cdot \left(b \cdot b\right)\right)}\right) - \frac{c \cdot \left(c \cdot a\right)}{b \cdot b}\right) - c}}{b} \]
  9. Final simplification95.0%

    \[\leadsto \frac{\left(\mathsf{fma}\left(-5 \cdot \left(c \cdot \left(c \cdot \left(c \cdot c\right)\right)\right), \frac{a \cdot \left(a \cdot a\right)}{\left(b \cdot b\right) \cdot \left(b \cdot \left(b \cdot \left(b \cdot b\right)\right)\right)}, \frac{\left(a \cdot a\right) \cdot \left(\left(c \cdot \left(c \cdot c\right)\right) \cdot -2\right)}{b \cdot \left(b \cdot \left(b \cdot b\right)\right)}\right) - \frac{c \cdot \left(c \cdot a\right)}{b \cdot b}\right) - c}{b} \]
  10. Add Preprocessing

Alternative 2: 95.8% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := b \cdot \left(b \cdot \left(b \cdot b\right)\right)\\ t_1 := c \cdot \left(c \cdot c\right)\\ \frac{\mathsf{fma}\left(-5 \cdot \left(c \cdot t\_1\right), \frac{a \cdot \left(a \cdot a\right)}{\left(b \cdot b\right) \cdot t\_0}, \frac{\left(a \cdot a\right) \cdot \left(t\_1 \cdot -2\right)}{t\_0}\right) - \mathsf{fma}\left(c \cdot a, \frac{c}{b \cdot b}, c\right)}{b} \end{array} \end{array} \]
(FPCore (a b c)
 :precision binary64
 (let* ((t_0 (* b (* b (* b b)))) (t_1 (* c (* c c))))
   (/
    (-
     (fma
      (* -5.0 (* c t_1))
      (/ (* a (* a a)) (* (* b b) t_0))
      (/ (* (* a a) (* t_1 -2.0)) t_0))
     (fma (* c a) (/ c (* b b)) c))
    b)))
double code(double a, double b, double c) {
	double t_0 = b * (b * (b * b));
	double t_1 = c * (c * c);
	return (fma((-5.0 * (c * t_1)), ((a * (a * a)) / ((b * b) * t_0)), (((a * a) * (t_1 * -2.0)) / t_0)) - fma((c * a), (c / (b * b)), c)) / b;
}
function code(a, b, c)
	t_0 = Float64(b * Float64(b * Float64(b * b)))
	t_1 = Float64(c * Float64(c * c))
	return Float64(Float64(fma(Float64(-5.0 * Float64(c * t_1)), Float64(Float64(a * Float64(a * a)) / Float64(Float64(b * b) * t_0)), Float64(Float64(Float64(a * a) * Float64(t_1 * -2.0)) / t_0)) - fma(Float64(c * a), Float64(c / Float64(b * b)), c)) / b)
end
code[a_, b_, c_] := Block[{t$95$0 = N[(b * N[(b * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(c * N[(c * c), $MachinePrecision]), $MachinePrecision]}, N[(N[(N[(N[(-5.0 * N[(c * t$95$1), $MachinePrecision]), $MachinePrecision] * N[(N[(a * N[(a * a), $MachinePrecision]), $MachinePrecision] / N[(N[(b * b), $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision] + N[(N[(N[(a * a), $MachinePrecision] * N[(t$95$1 * -2.0), $MachinePrecision]), $MachinePrecision] / t$95$0), $MachinePrecision]), $MachinePrecision] - N[(N[(c * a), $MachinePrecision] * N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] + c), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := b \cdot \left(b \cdot \left(b \cdot b\right)\right)\\
t_1 := c \cdot \left(c \cdot c\right)\\
\frac{\mathsf{fma}\left(-5 \cdot \left(c \cdot t\_1\right), \frac{a \cdot \left(a \cdot a\right)}{\left(b \cdot b\right) \cdot t\_0}, \frac{\left(a \cdot a\right) \cdot \left(t\_1 \cdot -2\right)}{t\_0}\right) - \mathsf{fma}\left(c \cdot a, \frac{c}{b \cdot b}, c\right)}{b}
\end{array}
\end{array}
Derivation
  1. Initial program 31.5%

    \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
  2. Add Preprocessing
  3. Taylor expanded in a around 0

    \[\leadsto \color{blue}{-1 \cdot \frac{c}{b} + a \cdot \left(-1 \cdot \frac{{c}^{2}}{{b}^{3}} + a \cdot \left(-2 \cdot \frac{{c}^{3}}{{b}^{5}} + \frac{-1}{4} \cdot \frac{a \cdot \left(4 \cdot \frac{{c}^{4}}{{b}^{6}} + 16 \cdot \frac{{c}^{4}}{{b}^{6}}\right)}{b}\right)\right)} \]
  4. Simplified94.9%

    \[\leadsto \color{blue}{\left(-\frac{\mathsf{fma}\left(c \cdot c, \frac{a}{b \cdot b}, c\right)}{b}\right) + \left(a \cdot a\right) \cdot \mathsf{fma}\left(\frac{{c}^{4} \cdot 20}{{b}^{6}} \cdot \frac{a}{b}, -0.25, \frac{\left(c \cdot \left(c \cdot c\right)\right) \cdot -2}{{b}^{5}}\right)} \]
  5. Taylor expanded in b around inf

    \[\leadsto \color{blue}{\frac{\left(-5 \cdot \frac{{a}^{3} \cdot {c}^{4}}{{b}^{6}} + -2 \cdot \frac{{a}^{2} \cdot {c}^{3}}{{b}^{4}}\right) - \left(c + \frac{a \cdot {c}^{2}}{{b}^{2}}\right)}{b}} \]
  6. Step-by-step derivation
    1. /-lowering-/.f64N/A

      \[\leadsto \color{blue}{\frac{\left(-5 \cdot \frac{{a}^{3} \cdot {c}^{4}}{{b}^{6}} + -2 \cdot \frac{{a}^{2} \cdot {c}^{3}}{{b}^{4}}\right) - \left(c + \frac{a \cdot {c}^{2}}{{b}^{2}}\right)}{b}} \]
  7. Simplified94.9%

    \[\leadsto \color{blue}{\frac{\mathsf{fma}\left(-5, \frac{{c}^{4} \cdot \left(a \cdot \left(a \cdot a\right)\right)}{{b}^{6}}, \frac{\left(-2 \cdot \left(a \cdot a\right)\right) \cdot \left(c \cdot \left(c \cdot c\right)\right)}{{b}^{4}}\right) - \mathsf{fma}\left(a, \frac{c \cdot c}{b \cdot b}, c\right)}{b}} \]
  8. Applied egg-rr94.9%

    \[\leadsto \frac{\color{blue}{\mathsf{fma}\left(-5 \cdot \left(c \cdot \left(c \cdot \left(c \cdot c\right)\right)\right), \frac{a \cdot \left(a \cdot a\right)}{\left(b \cdot \left(b \cdot \left(b \cdot b\right)\right)\right) \cdot \left(b \cdot b\right)}, \frac{\left(a \cdot a\right) \cdot \left(-2 \cdot \left(c \cdot \left(c \cdot c\right)\right)\right)}{b \cdot \left(b \cdot \left(b \cdot b\right)\right)}\right) - \mathsf{fma}\left(c \cdot a, \frac{c}{b \cdot b}, c\right)}}{b} \]
  9. Final simplification94.9%

    \[\leadsto \frac{\mathsf{fma}\left(-5 \cdot \left(c \cdot \left(c \cdot \left(c \cdot c\right)\right)\right), \frac{a \cdot \left(a \cdot a\right)}{\left(b \cdot b\right) \cdot \left(b \cdot \left(b \cdot \left(b \cdot b\right)\right)\right)}, \frac{\left(a \cdot a\right) \cdot \left(\left(c \cdot \left(c \cdot c\right)\right) \cdot -2\right)}{b \cdot \left(b \cdot \left(b \cdot b\right)\right)}\right) - \mathsf{fma}\left(c \cdot a, \frac{c}{b \cdot b}, c\right)}{b} \]
  10. Add Preprocessing

Alternative 3: 94.3% accurate, 0.6× speedup?

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

\\
\frac{\frac{\frac{\left(c \cdot \left(c \cdot c\right)\right) \cdot \left(\left(a \cdot a\right) \cdot -2\right)}{b \cdot b} - \left(c \cdot c\right) \cdot a}{b \cdot b} - c}{b}
\end{array}
Derivation
  1. Initial program 31.5%

    \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
  2. Add Preprocessing
  3. Taylor expanded in a around 0

    \[\leadsto \color{blue}{-1 \cdot \frac{c}{b} + a \cdot \left(-1 \cdot \frac{{c}^{2}}{{b}^{3}} + a \cdot \left(-2 \cdot \frac{{c}^{3}}{{b}^{5}} + \frac{-1}{4} \cdot \frac{a \cdot \left(4 \cdot \frac{{c}^{4}}{{b}^{6}} + 16 \cdot \frac{{c}^{4}}{{b}^{6}}\right)}{b}\right)\right)} \]
  4. Simplified94.9%

    \[\leadsto \color{blue}{\left(-\frac{\mathsf{fma}\left(c \cdot c, \frac{a}{b \cdot b}, c\right)}{b}\right) + \left(a \cdot a\right) \cdot \mathsf{fma}\left(\frac{{c}^{4} \cdot 20}{{b}^{6}} \cdot \frac{a}{b}, -0.25, \frac{\left(c \cdot \left(c \cdot c\right)\right) \cdot -2}{{b}^{5}}\right)} \]
  5. Taylor expanded in b around inf

    \[\leadsto \color{blue}{\frac{\left(-5 \cdot \frac{{a}^{3} \cdot {c}^{4}}{{b}^{6}} + -2 \cdot \frac{{a}^{2} \cdot {c}^{3}}{{b}^{4}}\right) - \left(c + \frac{a \cdot {c}^{2}}{{b}^{2}}\right)}{b}} \]
  6. Step-by-step derivation
    1. /-lowering-/.f64N/A

      \[\leadsto \color{blue}{\frac{\left(-5 \cdot \frac{{a}^{3} \cdot {c}^{4}}{{b}^{6}} + -2 \cdot \frac{{a}^{2} \cdot {c}^{3}}{{b}^{4}}\right) - \left(c + \frac{a \cdot {c}^{2}}{{b}^{2}}\right)}{b}} \]
  7. Simplified94.9%

    \[\leadsto \color{blue}{\frac{\mathsf{fma}\left(-5, \frac{{c}^{4} \cdot \left(a \cdot \left(a \cdot a\right)\right)}{{b}^{6}}, \frac{\left(-2 \cdot \left(a \cdot a\right)\right) \cdot \left(c \cdot \left(c \cdot c\right)\right)}{{b}^{4}}\right) - \mathsf{fma}\left(a, \frac{c \cdot c}{b \cdot b}, c\right)}{b}} \]
  8. Applied egg-rr95.0%

    \[\leadsto \frac{\color{blue}{\left(\mathsf{fma}\left(-5 \cdot \left(c \cdot \left(c \cdot \left(c \cdot c\right)\right)\right), \frac{a \cdot \left(a \cdot a\right)}{\left(b \cdot \left(b \cdot \left(b \cdot b\right)\right)\right) \cdot \left(b \cdot b\right)}, \frac{\left(a \cdot a\right) \cdot \left(-2 \cdot \left(c \cdot \left(c \cdot c\right)\right)\right)}{b \cdot \left(b \cdot \left(b \cdot b\right)\right)}\right) - \frac{c \cdot \left(c \cdot a\right)}{b \cdot b}\right) - c}}{b} \]
  9. Taylor expanded in b around inf

    \[\leadsto \frac{\color{blue}{\frac{-2 \cdot \frac{{a}^{2} \cdot {c}^{3}}{{b}^{2}} - a \cdot {c}^{2}}{{b}^{2}}} - c}{b} \]
  10. Step-by-step derivation
    1. /-lowering-/.f64N/A

      \[\leadsto \frac{\color{blue}{\frac{-2 \cdot \frac{{a}^{2} \cdot {c}^{3}}{{b}^{2}} - a \cdot {c}^{2}}{{b}^{2}}} - c}{b} \]
  11. Simplified93.5%

    \[\leadsto \frac{\color{blue}{\frac{\frac{\left(-2 \cdot \left(a \cdot a\right)\right) \cdot \left(c \cdot \left(c \cdot c\right)\right)}{b \cdot b} - a \cdot \left(c \cdot c\right)}{b \cdot b}} - c}{b} \]
  12. Final simplification93.5%

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

Alternative 4: 91.1% accurate, 1.1× speedup?

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

\\
-\mathsf{fma}\left(a, \frac{c \cdot c}{b \cdot \left(b \cdot b\right)}, \frac{c}{b}\right)
\end{array}
Derivation
  1. Initial program 31.5%

    \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
  2. Add Preprocessing
  3. Taylor expanded in a around 0

    \[\leadsto \color{blue}{-1 \cdot \frac{c}{b} + a \cdot \left(-1 \cdot \frac{{c}^{2}}{{b}^{3}} + a \cdot \left(-2 \cdot \frac{{c}^{3}}{{b}^{5}} + \frac{-1}{4} \cdot \frac{a \cdot \left(4 \cdot \frac{{c}^{4}}{{b}^{6}} + 16 \cdot \frac{{c}^{4}}{{b}^{6}}\right)}{b}\right)\right)} \]
  4. Simplified94.9%

    \[\leadsto \color{blue}{\left(-\frac{\mathsf{fma}\left(c \cdot c, \frac{a}{b \cdot b}, c\right)}{b}\right) + \left(a \cdot a\right) \cdot \mathsf{fma}\left(\frac{{c}^{4} \cdot 20}{{b}^{6}} \cdot \frac{a}{b}, -0.25, \frac{\left(c \cdot \left(c \cdot c\right)\right) \cdot -2}{{b}^{5}}\right)} \]
  5. Taylor expanded in a around 0

    \[\leadsto \color{blue}{-1 \cdot \frac{a \cdot {c}^{2}}{{b}^{3}} - \frac{c}{b}} \]
  6. Step-by-step derivation
    1. sub-negN/A

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

      \[\leadsto \color{blue}{\left(\mathsf{neg}\left(\frac{a \cdot {c}^{2}}{{b}^{3}}\right)\right)} + \left(\mathsf{neg}\left(\frac{c}{b}\right)\right) \]
    3. distribute-neg-outN/A

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

      \[\leadsto \color{blue}{\mathsf{neg}\left(\left(\frac{a \cdot {c}^{2}}{{b}^{3}} + \frac{c}{b}\right)\right)} \]
    5. associate-/l*N/A

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

      \[\leadsto \mathsf{neg}\left(\color{blue}{\mathsf{fma}\left(a, \frac{{c}^{2}}{{b}^{3}}, \frac{c}{b}\right)}\right) \]
    7. /-lowering-/.f64N/A

      \[\leadsto \mathsf{neg}\left(\mathsf{fma}\left(a, \color{blue}{\frac{{c}^{2}}{{b}^{3}}}, \frac{c}{b}\right)\right) \]
    8. unpow2N/A

      \[\leadsto \mathsf{neg}\left(\mathsf{fma}\left(a, \frac{\color{blue}{c \cdot c}}{{b}^{3}}, \frac{c}{b}\right)\right) \]
    9. *-lowering-*.f64N/A

      \[\leadsto \mathsf{neg}\left(\mathsf{fma}\left(a, \frac{\color{blue}{c \cdot c}}{{b}^{3}}, \frac{c}{b}\right)\right) \]
    10. cube-multN/A

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

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

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

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

      \[\leadsto \mathsf{neg}\left(\mathsf{fma}\left(a, \frac{c \cdot c}{b \cdot \color{blue}{\left(b \cdot b\right)}}, \frac{c}{b}\right)\right) \]
    15. /-lowering-/.f6490.7

      \[\leadsto -\mathsf{fma}\left(a, \frac{c \cdot c}{b \cdot \left(b \cdot b\right)}, \color{blue}{\frac{c}{b}}\right) \]
  7. Simplified90.7%

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

Alternative 5: 91.1% accurate, 1.2× speedup?

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

\\
\frac{\mathsf{fma}\left(c \cdot c, \frac{a}{b \cdot b}, c\right)}{-b}
\end{array}
Derivation
  1. Initial program 31.5%

    \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
  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-*.f6490.7

      \[\leadsto -\frac{\mathsf{fma}\left(c \cdot c, \frac{a}{\color{blue}{b \cdot b}}, c\right)}{b} \]
  5. Simplified90.7%

    \[\leadsto \color{blue}{-\frac{\mathsf{fma}\left(c \cdot c, \frac{a}{b \cdot b}, c\right)}{b}} \]
  6. Final simplification90.7%

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

Alternative 6: 81.6% accurate, 3.6× speedup?

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

\\
\frac{c}{-b}
\end{array}
Derivation
  1. Initial program 31.5%

    \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
  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. distribute-neg-frac2N/A

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

      \[\leadsto \color{blue}{\frac{c}{\mathsf{neg}\left(b\right)}} \]
    4. neg-lowering-neg.f6481.4

      \[\leadsto \frac{c}{\color{blue}{-b}} \]
  5. Simplified81.4%

    \[\leadsto \color{blue}{\frac{c}{-b}} \]
  6. Add Preprocessing

Reproduce

?
herbie shell --seed 2024204 
(FPCore (a b c)
  :name "Quadratic roots, medium range"
  :precision binary64
  :pre (and (and (and (< 1.1102230246251565e-16 a) (< a 9007199254740992.0)) (and (< 1.1102230246251565e-16 b) (< b 9007199254740992.0))) (and (< 1.1102230246251565e-16 c) (< c 9007199254740992.0)))
  (/ (+ (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))) (* 2.0 a)))