Quadratic roots, wide range

Percentage Accurate: 18.1% → 97.5%
Time: 9.1s
Alternatives: 5
Speedup: 29.0×

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 5 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: 18.1% 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: 97.5% accurate, 0.2× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(-2, \frac{a}{\frac{\frac{{b}^{5}}{{c}^{3}}}{a}}, \mathsf{fma}\left(-0.25, \frac{{\left(a \cdot c\right)}^{4}}{a} \cdot \frac{20}{{b}^{7}}, \frac{-a}{\frac{\frac{{b}^{3}}{c}}{c}}\right) - \frac{c}{b}\right) \end{array} \]
(FPCore (a b c)
 :precision binary64
 (fma
  -2.0
  (/ a (/ (/ (pow b 5.0) (pow c 3.0)) a))
  (-
   (fma
    -0.25
    (* (/ (pow (* a c) 4.0) a) (/ 20.0 (pow b 7.0)))
    (/ (- a) (/ (/ (pow b 3.0) c) c)))
   (/ c b))))
double code(double a, double b, double c) {
	return fma(-2.0, (a / ((pow(b, 5.0) / pow(c, 3.0)) / a)), (fma(-0.25, ((pow((a * c), 4.0) / a) * (20.0 / pow(b, 7.0))), (-a / ((pow(b, 3.0) / c) / c))) - (c / b)));
}
function code(a, b, c)
	return fma(-2.0, Float64(a / Float64(Float64((b ^ 5.0) / (c ^ 3.0)) / a)), Float64(fma(-0.25, Float64(Float64((Float64(a * c) ^ 4.0) / a) * Float64(20.0 / (b ^ 7.0))), Float64(Float64(-a) / Float64(Float64((b ^ 3.0) / c) / c))) - Float64(c / b)))
end
code[a_, b_, c_] := N[(-2.0 * N[(a / N[(N[(N[Power[b, 5.0], $MachinePrecision] / N[Power[c, 3.0], $MachinePrecision]), $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision] + N[(N[(-0.25 * N[(N[(N[Power[N[(a * c), $MachinePrecision], 4.0], $MachinePrecision] / a), $MachinePrecision] * N[(20.0 / N[Power[b, 7.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[((-a) / N[(N[(N[Power[b, 3.0], $MachinePrecision] / c), $MachinePrecision] / c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(c / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\mathsf{fma}\left(-2, \frac{a}{\frac{\frac{{b}^{5}}{{c}^{3}}}{a}}, \mathsf{fma}\left(-0.25, \frac{{\left(a \cdot c\right)}^{4}}{a} \cdot \frac{20}{{b}^{7}}, \frac{-a}{\frac{\frac{{b}^{3}}{c}}{c}}\right) - \frac{c}{b}\right)
\end{array}
Derivation
  1. Initial program 16.7%

    \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
  2. Step-by-step derivation
    1. Simplified16.7%

      \[\leadsto \color{blue}{\frac{\sqrt{\mathsf{fma}\left(b, b, c \cdot \left(a \cdot -4\right)\right)} - b}{a \cdot 2}} \]
    2. Step-by-step derivation
      1. *-commutative16.7%

        \[\leadsto \frac{\sqrt{\mathsf{fma}\left(b, b, c \cdot \color{blue}{\left(-4 \cdot a\right)}\right)} - b}{a \cdot 2} \]
      2. metadata-eval16.7%

        \[\leadsto \frac{\sqrt{\mathsf{fma}\left(b, b, c \cdot \left(\color{blue}{\left(-4\right)} \cdot a\right)\right)} - b}{a \cdot 2} \]
      3. distribute-lft-neg-in16.7%

        \[\leadsto \frac{\sqrt{\mathsf{fma}\left(b, b, c \cdot \color{blue}{\left(-4 \cdot a\right)}\right)} - b}{a \cdot 2} \]
      4. distribute-rgt-neg-in16.7%

        \[\leadsto \frac{\sqrt{\mathsf{fma}\left(b, b, \color{blue}{-c \cdot \left(4 \cdot a\right)}\right)} - b}{a \cdot 2} \]
      5. *-commutative16.7%

        \[\leadsto \frac{\sqrt{\mathsf{fma}\left(b, b, -\color{blue}{\left(4 \cdot a\right) \cdot c}\right)} - b}{a \cdot 2} \]
      6. fma-neg16.7%

        \[\leadsto \frac{\sqrt{\color{blue}{b \cdot b - \left(4 \cdot a\right) \cdot c}} - b}{a \cdot 2} \]
      7. associate-*l*16.7%

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

      \[\leadsto \frac{\sqrt{\color{blue}{b \cdot b - 4 \cdot \left(a \cdot c\right)}} - b}{a \cdot 2} \]
    4. Taylor expanded in b around inf 98.0%

      \[\leadsto \color{blue}{-2 \cdot \frac{{a}^{2} \cdot {c}^{3}}{{b}^{5}} + \left(-1 \cdot \frac{c}{b} + \left(-1 \cdot \frac{a \cdot {c}^{2}}{{b}^{3}} + -0.25 \cdot \frac{16 \cdot \left({a}^{4} \cdot {c}^{4}\right) + {\left(-2 \cdot \left({a}^{2} \cdot {c}^{2}\right)\right)}^{2}}{a \cdot {b}^{7}}\right)\right)} \]
    5. Simplified98.0%

      \[\leadsto \color{blue}{\mathsf{fma}\left(-2, \frac{a}{\frac{\frac{{b}^{5}}{{c}^{3}}}{a}}, \mathsf{fma}\left(-0.25, \frac{\mathsf{fma}\left(16, {\left(a \cdot c\right)}^{4}, 4 \cdot {\left(a \cdot c\right)}^{4}\right)}{a \cdot {b}^{7}}, \frac{-a}{\frac{\frac{{b}^{3}}{c}}{c}}\right) - \frac{c}{b}\right)} \]
    6. Taylor expanded in c around 0 98.0%

      \[\leadsto \mathsf{fma}\left(-2, \frac{a}{\frac{\frac{{b}^{5}}{{c}^{3}}}{a}}, \mathsf{fma}\left(-0.25, \color{blue}{\frac{{c}^{4} \cdot \left(4 \cdot {a}^{4} + 16 \cdot {a}^{4}\right)}{a \cdot {b}^{7}}}, \frac{-a}{\frac{\frac{{b}^{3}}{c}}{c}}\right) - \frac{c}{b}\right) \]
    7. Step-by-step derivation
      1. distribute-rgt-out98.0%

        \[\leadsto \mathsf{fma}\left(-2, \frac{a}{\frac{\frac{{b}^{5}}{{c}^{3}}}{a}}, \mathsf{fma}\left(-0.25, \frac{{c}^{4} \cdot \color{blue}{\left({a}^{4} \cdot \left(4 + 16\right)\right)}}{a \cdot {b}^{7}}, \frac{-a}{\frac{\frac{{b}^{3}}{c}}{c}}\right) - \frac{c}{b}\right) \]
      2. associate-*r*98.0%

        \[\leadsto \mathsf{fma}\left(-2, \frac{a}{\frac{\frac{{b}^{5}}{{c}^{3}}}{a}}, \mathsf{fma}\left(-0.25, \frac{\color{blue}{\left({c}^{4} \cdot {a}^{4}\right) \cdot \left(4 + 16\right)}}{a \cdot {b}^{7}}, \frac{-a}{\frac{\frac{{b}^{3}}{c}}{c}}\right) - \frac{c}{b}\right) \]
      3. *-commutative98.0%

        \[\leadsto \mathsf{fma}\left(-2, \frac{a}{\frac{\frac{{b}^{5}}{{c}^{3}}}{a}}, \mathsf{fma}\left(-0.25, \frac{\color{blue}{\left({a}^{4} \cdot {c}^{4}\right)} \cdot \left(4 + 16\right)}{a \cdot {b}^{7}}, \frac{-a}{\frac{\frac{{b}^{3}}{c}}{c}}\right) - \frac{c}{b}\right) \]
      4. times-frac98.0%

        \[\leadsto \mathsf{fma}\left(-2, \frac{a}{\frac{\frac{{b}^{5}}{{c}^{3}}}{a}}, \mathsf{fma}\left(-0.25, \color{blue}{\frac{{a}^{4} \cdot {c}^{4}}{a} \cdot \frac{4 + 16}{{b}^{7}}}, \frac{-a}{\frac{\frac{{b}^{3}}{c}}{c}}\right) - \frac{c}{b}\right) \]
    8. Simplified98.0%

      \[\leadsto \mathsf{fma}\left(-2, \frac{a}{\frac{\frac{{b}^{5}}{{c}^{3}}}{a}}, \mathsf{fma}\left(-0.25, \color{blue}{\frac{{\left(a \cdot c\right)}^{4}}{a} \cdot \frac{20}{{b}^{7}}}, \frac{-a}{\frac{\frac{{b}^{3}}{c}}{c}}\right) - \frac{c}{b}\right) \]
    9. Final simplification98.0%

      \[\leadsto \mathsf{fma}\left(-2, \frac{a}{\frac{\frac{{b}^{5}}{{c}^{3}}}{a}}, \mathsf{fma}\left(-0.25, \frac{{\left(a \cdot c\right)}^{4}}{a} \cdot \frac{20}{{b}^{7}}, \frac{-a}{\frac{\frac{{b}^{3}}{c}}{c}}\right) - \frac{c}{b}\right) \]

    Alternative 2: 96.7% accurate, 0.4× speedup?

    \[\begin{array}{l} \\ \left(\frac{-2 \cdot \left(a \cdot a\right)}{\frac{{b}^{5}}{{c}^{3}}} - \frac{c}{b}\right) - \frac{a}{{b}^{3}} \cdot \left(c \cdot c\right) \end{array} \]
    (FPCore (a b c)
     :precision binary64
     (-
      (- (/ (* -2.0 (* a a)) (/ (pow b 5.0) (pow c 3.0))) (/ c b))
      (* (/ a (pow b 3.0)) (* c c))))
    double code(double a, double b, double c) {
    	return (((-2.0 * (a * a)) / (pow(b, 5.0) / pow(c, 3.0))) - (c / b)) - ((a / pow(b, 3.0)) * (c * c));
    }
    
    real(8) function code(a, b, c)
        real(8), intent (in) :: a
        real(8), intent (in) :: b
        real(8), intent (in) :: c
        code = ((((-2.0d0) * (a * a)) / ((b ** 5.0d0) / (c ** 3.0d0))) - (c / b)) - ((a / (b ** 3.0d0)) * (c * c))
    end function
    
    public static double code(double a, double b, double c) {
    	return (((-2.0 * (a * a)) / (Math.pow(b, 5.0) / Math.pow(c, 3.0))) - (c / b)) - ((a / Math.pow(b, 3.0)) * (c * c));
    }
    
    def code(a, b, c):
    	return (((-2.0 * (a * a)) / (math.pow(b, 5.0) / math.pow(c, 3.0))) - (c / b)) - ((a / math.pow(b, 3.0)) * (c * c))
    
    function code(a, b, c)
    	return Float64(Float64(Float64(Float64(-2.0 * Float64(a * a)) / Float64((b ^ 5.0) / (c ^ 3.0))) - Float64(c / b)) - Float64(Float64(a / (b ^ 3.0)) * Float64(c * c)))
    end
    
    function tmp = code(a, b, c)
    	tmp = (((-2.0 * (a * a)) / ((b ^ 5.0) / (c ^ 3.0))) - (c / b)) - ((a / (b ^ 3.0)) * (c * c));
    end
    
    code[a_, b_, c_] := N[(N[(N[(N[(-2.0 * N[(a * a), $MachinePrecision]), $MachinePrecision] / N[(N[Power[b, 5.0], $MachinePrecision] / N[Power[c, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(c / b), $MachinePrecision]), $MachinePrecision] - N[(N[(a / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision] * N[(c * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
    
    \begin{array}{l}
    
    \\
    \left(\frac{-2 \cdot \left(a \cdot a\right)}{\frac{{b}^{5}}{{c}^{3}}} - \frac{c}{b}\right) - \frac{a}{{b}^{3}} \cdot \left(c \cdot c\right)
    \end{array}
    
    Derivation
    1. Initial program 16.7%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Taylor expanded in b around inf 97.5%

      \[\leadsto \color{blue}{-2 \cdot \frac{{a}^{2} \cdot {c}^{3}}{{b}^{5}} + \left(-1 \cdot \frac{c}{b} + -1 \cdot \frac{a \cdot {c}^{2}}{{b}^{3}}\right)} \]
    3. Step-by-step derivation
      1. associate-+r+97.5%

        \[\leadsto \color{blue}{\left(-2 \cdot \frac{{a}^{2} \cdot {c}^{3}}{{b}^{5}} + -1 \cdot \frac{c}{b}\right) + -1 \cdot \frac{a \cdot {c}^{2}}{{b}^{3}}} \]
      2. mul-1-neg97.5%

        \[\leadsto \left(-2 \cdot \frac{{a}^{2} \cdot {c}^{3}}{{b}^{5}} + -1 \cdot \frac{c}{b}\right) + \color{blue}{\left(-\frac{a \cdot {c}^{2}}{{b}^{3}}\right)} \]
      3. unsub-neg97.5%

        \[\leadsto \color{blue}{\left(-2 \cdot \frac{{a}^{2} \cdot {c}^{3}}{{b}^{5}} + -1 \cdot \frac{c}{b}\right) - \frac{a \cdot {c}^{2}}{{b}^{3}}} \]
      4. mul-1-neg97.5%

        \[\leadsto \left(-2 \cdot \frac{{a}^{2} \cdot {c}^{3}}{{b}^{5}} + \color{blue}{\left(-\frac{c}{b}\right)}\right) - \frac{a \cdot {c}^{2}}{{b}^{3}} \]
      5. unsub-neg97.5%

        \[\leadsto \color{blue}{\left(-2 \cdot \frac{{a}^{2} \cdot {c}^{3}}{{b}^{5}} - \frac{c}{b}\right)} - \frac{a \cdot {c}^{2}}{{b}^{3}} \]
      6. associate-/l*97.5%

        \[\leadsto \left(-2 \cdot \color{blue}{\frac{{a}^{2}}{\frac{{b}^{5}}{{c}^{3}}}} - \frac{c}{b}\right) - \frac{a \cdot {c}^{2}}{{b}^{3}} \]
      7. associate-*r/97.5%

        \[\leadsto \left(\color{blue}{\frac{-2 \cdot {a}^{2}}{\frac{{b}^{5}}{{c}^{3}}}} - \frac{c}{b}\right) - \frac{a \cdot {c}^{2}}{{b}^{3}} \]
      8. unpow297.5%

        \[\leadsto \left(\frac{-2 \cdot \color{blue}{\left(a \cdot a\right)}}{\frac{{b}^{5}}{{c}^{3}}} - \frac{c}{b}\right) - \frac{a \cdot {c}^{2}}{{b}^{3}} \]
      9. associate-/l*97.5%

        \[\leadsto \left(\frac{-2 \cdot \left(a \cdot a\right)}{\frac{{b}^{5}}{{c}^{3}}} - \frac{c}{b}\right) - \color{blue}{\frac{a}{\frac{{b}^{3}}{{c}^{2}}}} \]
      10. associate-/r/97.5%

        \[\leadsto \left(\frac{-2 \cdot \left(a \cdot a\right)}{\frac{{b}^{5}}{{c}^{3}}} - \frac{c}{b}\right) - \color{blue}{\frac{a}{{b}^{3}} \cdot {c}^{2}} \]
      11. unpow297.5%

        \[\leadsto \left(\frac{-2 \cdot \left(a \cdot a\right)}{\frac{{b}^{5}}{{c}^{3}}} - \frac{c}{b}\right) - \frac{a}{{b}^{3}} \cdot \color{blue}{\left(c \cdot c\right)} \]
    4. Simplified97.5%

      \[\leadsto \color{blue}{\left(\frac{-2 \cdot \left(a \cdot a\right)}{\frac{{b}^{5}}{{c}^{3}}} - \frac{c}{b}\right) - \frac{a}{{b}^{3}} \cdot \left(c \cdot c\right)} \]
    5. Final simplification97.5%

      \[\leadsto \left(\frac{-2 \cdot \left(a \cdot a\right)}{\frac{{b}^{5}}{{c}^{3}}} - \frac{c}{b}\right) - \frac{a}{{b}^{3}} \cdot \left(c \cdot c\right) \]

    Alternative 3: 95.1% accurate, 1.0× speedup?

    \[\begin{array}{l} \\ \frac{-c}{b} - \frac{a}{{b}^{3}} \cdot \left(c \cdot c\right) \end{array} \]
    (FPCore (a b c)
     :precision binary64
     (- (/ (- c) b) (* (/ a (pow b 3.0)) (* c c))))
    double code(double a, double b, double c) {
    	return (-c / b) - ((a / pow(b, 3.0)) * (c * c));
    }
    
    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) - ((a / (b ** 3.0d0)) * (c * c))
    end function
    
    public static double code(double a, double b, double c) {
    	return (-c / b) - ((a / Math.pow(b, 3.0)) * (c * c));
    }
    
    def code(a, b, c):
    	return (-c / b) - ((a / math.pow(b, 3.0)) * (c * c))
    
    function code(a, b, c)
    	return Float64(Float64(Float64(-c) / b) - Float64(Float64(a / (b ^ 3.0)) * Float64(c * c)))
    end
    
    function tmp = code(a, b, c)
    	tmp = (-c / b) - ((a / (b ^ 3.0)) * (c * c));
    end
    
    code[a_, b_, c_] := N[(N[((-c) / b), $MachinePrecision] - N[(N[(a / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision] * N[(c * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
    
    \begin{array}{l}
    
    \\
    \frac{-c}{b} - \frac{a}{{b}^{3}} \cdot \left(c \cdot c\right)
    \end{array}
    
    Derivation
    1. Initial program 16.7%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Taylor expanded in b around inf 96.5%

      \[\leadsto \color{blue}{-1 \cdot \frac{c}{b} + -1 \cdot \frac{a \cdot {c}^{2}}{{b}^{3}}} \]
    3. Step-by-step derivation
      1. mul-1-neg96.5%

        \[\leadsto -1 \cdot \frac{c}{b} + \color{blue}{\left(-\frac{a \cdot {c}^{2}}{{b}^{3}}\right)} \]
      2. unsub-neg96.5%

        \[\leadsto \color{blue}{-1 \cdot \frac{c}{b} - \frac{a \cdot {c}^{2}}{{b}^{3}}} \]
      3. mul-1-neg96.5%

        \[\leadsto \color{blue}{\left(-\frac{c}{b}\right)} - \frac{a \cdot {c}^{2}}{{b}^{3}} \]
      4. distribute-neg-frac96.5%

        \[\leadsto \color{blue}{\frac{-c}{b}} - \frac{a \cdot {c}^{2}}{{b}^{3}} \]
      5. associate-/l*96.5%

        \[\leadsto \frac{-c}{b} - \color{blue}{\frac{a}{\frac{{b}^{3}}{{c}^{2}}}} \]
      6. associate-/r/96.5%

        \[\leadsto \frac{-c}{b} - \color{blue}{\frac{a}{{b}^{3}} \cdot {c}^{2}} \]
      7. unpow296.5%

        \[\leadsto \frac{-c}{b} - \frac{a}{{b}^{3}} \cdot \color{blue}{\left(c \cdot c\right)} \]
    4. Simplified96.5%

      \[\leadsto \color{blue}{\frac{-c}{b} - \frac{a}{{b}^{3}} \cdot \left(c \cdot c\right)} \]
    5. Final simplification96.5%

      \[\leadsto \frac{-c}{b} - \frac{a}{{b}^{3}} \cdot \left(c \cdot c\right) \]

    Alternative 4: 94.8% accurate, 5.3× speedup?

    \[\begin{array}{l} \\ \frac{\frac{a \cdot \left(c \cdot 4\right)}{\left(-b\right) - \left(b + -2 \cdot \left(c \cdot \frac{a}{b}\right)\right)}}{a \cdot 2} \end{array} \]
    (FPCore (a b c)
     :precision binary64
     (/ (/ (* a (* c 4.0)) (- (- b) (+ b (* -2.0 (* c (/ a b)))))) (* a 2.0)))
    double code(double a, double b, double c) {
    	return ((a * (c * 4.0)) / (-b - (b + (-2.0 * (c * (a / b)))))) / (a * 2.0);
    }
    
    real(8) function code(a, b, c)
        real(8), intent (in) :: a
        real(8), intent (in) :: b
        real(8), intent (in) :: c
        code = ((a * (c * 4.0d0)) / (-b - (b + ((-2.0d0) * (c * (a / b)))))) / (a * 2.0d0)
    end function
    
    public static double code(double a, double b, double c) {
    	return ((a * (c * 4.0)) / (-b - (b + (-2.0 * (c * (a / b)))))) / (a * 2.0);
    }
    
    def code(a, b, c):
    	return ((a * (c * 4.0)) / (-b - (b + (-2.0 * (c * (a / b)))))) / (a * 2.0)
    
    function code(a, b, c)
    	return Float64(Float64(Float64(a * Float64(c * 4.0)) / Float64(Float64(-b) - Float64(b + Float64(-2.0 * Float64(c * Float64(a / b)))))) / Float64(a * 2.0))
    end
    
    function tmp = code(a, b, c)
    	tmp = ((a * (c * 4.0)) / (-b - (b + (-2.0 * (c * (a / b)))))) / (a * 2.0);
    end
    
    code[a_, b_, c_] := N[(N[(N[(a * N[(c * 4.0), $MachinePrecision]), $MachinePrecision] / N[((-b) - N[(b + N[(-2.0 * N[(c * N[(a / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(a * 2.0), $MachinePrecision]), $MachinePrecision]
    
    \begin{array}{l}
    
    \\
    \frac{\frac{a \cdot \left(c \cdot 4\right)}{\left(-b\right) - \left(b + -2 \cdot \left(c \cdot \frac{a}{b}\right)\right)}}{a \cdot 2}
    \end{array}
    
    Derivation
    1. Initial program 16.7%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Taylor expanded in b around inf 13.0%

      \[\leadsto \frac{\left(-b\right) + \color{blue}{\left(b + -2 \cdot \frac{a \cdot c}{b}\right)}}{2 \cdot a} \]
    3. Step-by-step derivation
      1. flip-+13.0%

        \[\leadsto \frac{\color{blue}{\frac{\left(-b\right) \cdot \left(-b\right) - \left(b + -2 \cdot \frac{a \cdot c}{b}\right) \cdot \left(b + -2 \cdot \frac{a \cdot c}{b}\right)}{\left(-b\right) - \left(b + -2 \cdot \frac{a \cdot c}{b}\right)}}}{2 \cdot a} \]
      2. associate-/l*13.0%

        \[\leadsto \frac{\frac{\left(-b\right) \cdot \left(-b\right) - \left(b + -2 \cdot \color{blue}{\frac{a}{\frac{b}{c}}}\right) \cdot \left(b + -2 \cdot \frac{a \cdot c}{b}\right)}{\left(-b\right) - \left(b + -2 \cdot \frac{a \cdot c}{b}\right)}}{2 \cdot a} \]
      3. associate-/r/13.0%

        \[\leadsto \frac{\frac{\left(-b\right) \cdot \left(-b\right) - \left(b + -2 \cdot \color{blue}{\left(\frac{a}{b} \cdot c\right)}\right) \cdot \left(b + -2 \cdot \frac{a \cdot c}{b}\right)}{\left(-b\right) - \left(b + -2 \cdot \frac{a \cdot c}{b}\right)}}{2 \cdot a} \]
      4. associate-/l*13.0%

        \[\leadsto \frac{\frac{\left(-b\right) \cdot \left(-b\right) - \left(b + -2 \cdot \left(\frac{a}{b} \cdot c\right)\right) \cdot \left(b + -2 \cdot \color{blue}{\frac{a}{\frac{b}{c}}}\right)}{\left(-b\right) - \left(b + -2 \cdot \frac{a \cdot c}{b}\right)}}{2 \cdot a} \]
      5. associate-/r/13.0%

        \[\leadsto \frac{\frac{\left(-b\right) \cdot \left(-b\right) - \left(b + -2 \cdot \left(\frac{a}{b} \cdot c\right)\right) \cdot \left(b + -2 \cdot \color{blue}{\left(\frac{a}{b} \cdot c\right)}\right)}{\left(-b\right) - \left(b + -2 \cdot \frac{a \cdot c}{b}\right)}}{2 \cdot a} \]
      6. associate-/l*13.0%

        \[\leadsto \frac{\frac{\left(-b\right) \cdot \left(-b\right) - \left(b + -2 \cdot \left(\frac{a}{b} \cdot c\right)\right) \cdot \left(b + -2 \cdot \left(\frac{a}{b} \cdot c\right)\right)}{\left(-b\right) - \left(b + -2 \cdot \color{blue}{\frac{a}{\frac{b}{c}}}\right)}}{2 \cdot a} \]
      7. associate-/r/13.0%

        \[\leadsto \frac{\frac{\left(-b\right) \cdot \left(-b\right) - \left(b + -2 \cdot \left(\frac{a}{b} \cdot c\right)\right) \cdot \left(b + -2 \cdot \left(\frac{a}{b} \cdot c\right)\right)}{\left(-b\right) - \left(b + -2 \cdot \color{blue}{\left(\frac{a}{b} \cdot c\right)}\right)}}{2 \cdot a} \]
    4. Applied egg-rr13.0%

      \[\leadsto \frac{\color{blue}{\frac{\left(-b\right) \cdot \left(-b\right) - \left(b + -2 \cdot \left(\frac{a}{b} \cdot c\right)\right) \cdot \left(b + -2 \cdot \left(\frac{a}{b} \cdot c\right)\right)}{\left(-b\right) - \left(b + -2 \cdot \left(\frac{a}{b} \cdot c\right)\right)}}}{2 \cdot a} \]
    5. Step-by-step derivation
      1. sqr-neg13.0%

        \[\leadsto \frac{\frac{\color{blue}{b \cdot b} - \left(b + -2 \cdot \left(\frac{a}{b} \cdot c\right)\right) \cdot \left(b + -2 \cdot \left(\frac{a}{b} \cdot c\right)\right)}{\left(-b\right) - \left(b + -2 \cdot \left(\frac{a}{b} \cdot c\right)\right)}}{2 \cdot a} \]
      2. *-commutative13.0%

        \[\leadsto \frac{\frac{b \cdot b - \left(b + -2 \cdot \color{blue}{\left(c \cdot \frac{a}{b}\right)}\right) \cdot \left(b + -2 \cdot \left(\frac{a}{b} \cdot c\right)\right)}{\left(-b\right) - \left(b + -2 \cdot \left(\frac{a}{b} \cdot c\right)\right)}}{2 \cdot a} \]
      3. *-commutative13.0%

        \[\leadsto \frac{\frac{b \cdot b - \left(b + -2 \cdot \left(c \cdot \frac{a}{b}\right)\right) \cdot \left(b + -2 \cdot \color{blue}{\left(c \cdot \frac{a}{b}\right)}\right)}{\left(-b\right) - \left(b + -2 \cdot \left(\frac{a}{b} \cdot c\right)\right)}}{2 \cdot a} \]
      4. *-commutative13.0%

        \[\leadsto \frac{\frac{b \cdot b - \left(b + -2 \cdot \left(c \cdot \frac{a}{b}\right)\right) \cdot \left(b + -2 \cdot \left(c \cdot \frac{a}{b}\right)\right)}{\left(-b\right) - \left(b + -2 \cdot \color{blue}{\left(c \cdot \frac{a}{b}\right)}\right)}}{2 \cdot a} \]
    6. Simplified13.0%

      \[\leadsto \frac{\color{blue}{\frac{b \cdot b - \left(b + -2 \cdot \left(c \cdot \frac{a}{b}\right)\right) \cdot \left(b + -2 \cdot \left(c \cdot \frac{a}{b}\right)\right)}{\left(-b\right) - \left(b + -2 \cdot \left(c \cdot \frac{a}{b}\right)\right)}}}{2 \cdot a} \]
    7. Taylor expanded in b around inf 96.2%

      \[\leadsto \frac{\frac{\color{blue}{4 \cdot \left(a \cdot c\right)}}{\left(-b\right) - \left(b + -2 \cdot \left(c \cdot \frac{a}{b}\right)\right)}}{2 \cdot a} \]
    8. Step-by-step derivation
      1. *-commutative96.2%

        \[\leadsto \frac{\frac{\color{blue}{\left(a \cdot c\right) \cdot 4}}{\left(-b\right) - \left(b + -2 \cdot \left(c \cdot \frac{a}{b}\right)\right)}}{2 \cdot a} \]
      2. associate-*l*96.2%

        \[\leadsto \frac{\frac{\color{blue}{a \cdot \left(c \cdot 4\right)}}{\left(-b\right) - \left(b + -2 \cdot \left(c \cdot \frac{a}{b}\right)\right)}}{2 \cdot a} \]
    9. Simplified96.2%

      \[\leadsto \frac{\frac{\color{blue}{a \cdot \left(c \cdot 4\right)}}{\left(-b\right) - \left(b + -2 \cdot \left(c \cdot \frac{a}{b}\right)\right)}}{2 \cdot a} \]
    10. Final simplification96.2%

      \[\leadsto \frac{\frac{a \cdot \left(c \cdot 4\right)}{\left(-b\right) - \left(b + -2 \cdot \left(c \cdot \frac{a}{b}\right)\right)}}{a \cdot 2} \]

    Alternative 5: 90.2% accurate, 29.0× 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(Float64(-c) / b)
    end
    
    function tmp = code(a, b, c)
    	tmp = -c / b;
    end
    
    code[a_, b_, c_] := N[((-c) / b), $MachinePrecision]
    
    \begin{array}{l}
    
    \\
    \frac{-c}{b}
    \end{array}
    
    Derivation
    1. Initial program 16.7%

      \[\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a} \]
    2. Taylor expanded in b around inf 91.3%

      \[\leadsto \color{blue}{-1 \cdot \frac{c}{b}} \]
    3. Step-by-step derivation
      1. mul-1-neg91.3%

        \[\leadsto \color{blue}{-\frac{c}{b}} \]
      2. distribute-neg-frac91.3%

        \[\leadsto \color{blue}{\frac{-c}{b}} \]
    4. Simplified91.3%

      \[\leadsto \color{blue}{\frac{-c}{b}} \]
    5. Final simplification91.3%

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

    Reproduce

    ?
    herbie shell --seed 2023272 
    (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)))