
(FPCore (a b c) :precision binary64 (/ (+ (- b) (sqrt (- (* b b) (* (* 3.0 a) c)))) (* 3.0 a)))
double code(double a, double b, double c) {
return (-b + sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * 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) - ((3.0d0 * a) * c)))) / (3.0d0 * a)
end function
public static double code(double a, double b, double c) {
return (-b + Math.sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a);
}
def code(a, b, c): return (-b + math.sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a)
function code(a, b, c) return Float64(Float64(Float64(-b) + sqrt(Float64(Float64(b * b) - Float64(Float64(3.0 * a) * c)))) / Float64(3.0 * a)) end
function tmp = code(a, b, c) tmp = (-b + sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a); end
code[a_, b_, c_] := N[(N[((-b) + N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(3.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(3.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-b\right) + \sqrt{b \cdot b - \left(3 \cdot a\right) \cdot c}}{3 \cdot a}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 6 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (a b c) :precision binary64 (/ (+ (- b) (sqrt (- (* b b) (* (* 3.0 a) c)))) (* 3.0 a)))
double code(double a, double b, double c) {
return (-b + sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * 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) - ((3.0d0 * a) * c)))) / (3.0d0 * a)
end function
public static double code(double a, double b, double c) {
return (-b + Math.sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a);
}
def code(a, b, c): return (-b + math.sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a)
function code(a, b, c) return Float64(Float64(Float64(-b) + sqrt(Float64(Float64(b * b) - Float64(Float64(3.0 * a) * c)))) / Float64(3.0 * a)) end
function tmp = code(a, b, c) tmp = (-b + sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a); end
code[a_, b_, c_] := N[(N[((-b) + N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(3.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(3.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-b\right) + \sqrt{b \cdot b - \left(3 \cdot a\right) \cdot c}}{3 \cdot a}
\end{array}
(FPCore (a b c)
:precision binary64
(let* ((t_0 (* a (* 3.0 c))))
(/
(/
(+ (- (pow (- b) 2.0) (pow b 2.0)) t_0)
(- (- b) (sqrt (- (pow b 2.0) t_0))))
(* a 3.0))))
double code(double a, double b, double c) {
double t_0 = a * (3.0 * c);
return (((pow(-b, 2.0) - pow(b, 2.0)) + t_0) / (-b - sqrt((pow(b, 2.0) - t_0)))) / (a * 3.0);
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
real(8) :: t_0
t_0 = a * (3.0d0 * c)
code = ((((-b ** 2.0d0) - (b ** 2.0d0)) + t_0) / (-b - sqrt(((b ** 2.0d0) - t_0)))) / (a * 3.0d0)
end function
public static double code(double a, double b, double c) {
double t_0 = a * (3.0 * c);
return (((Math.pow(-b, 2.0) - Math.pow(b, 2.0)) + t_0) / (-b - Math.sqrt((Math.pow(b, 2.0) - t_0)))) / (a * 3.0);
}
def code(a, b, c): t_0 = a * (3.0 * c) return (((math.pow(-b, 2.0) - math.pow(b, 2.0)) + t_0) / (-b - math.sqrt((math.pow(b, 2.0) - t_0)))) / (a * 3.0)
function code(a, b, c) t_0 = Float64(a * Float64(3.0 * c)) return Float64(Float64(Float64(Float64((Float64(-b) ^ 2.0) - (b ^ 2.0)) + t_0) / Float64(Float64(-b) - sqrt(Float64((b ^ 2.0) - t_0)))) / Float64(a * 3.0)) end
function tmp = code(a, b, c) t_0 = a * (3.0 * c); tmp = ((((-b ^ 2.0) - (b ^ 2.0)) + t_0) / (-b - sqrt(((b ^ 2.0) - t_0)))) / (a * 3.0); end
code[a_, b_, c_] := Block[{t$95$0 = N[(a * N[(3.0 * c), $MachinePrecision]), $MachinePrecision]}, N[(N[(N[(N[(N[Power[(-b), 2.0], $MachinePrecision] - N[Power[b, 2.0], $MachinePrecision]), $MachinePrecision] + t$95$0), $MachinePrecision] / N[((-b) - N[Sqrt[N[(N[Power[b, 2.0], $MachinePrecision] - t$95$0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := a \cdot \left(3 \cdot c\right)\\
\frac{\frac{\left({\left(-b\right)}^{2} - {b}^{2}\right) + t_0}{\left(-b\right) - \sqrt{{b}^{2} - t_0}}}{a \cdot 3}
\end{array}
\end{array}
(FPCore (a b c)
:precision binary64
(let* ((t_0 (/ (- (sqrt (fma b b (* a (* c -3.0)))) b) (* a 3.0)))
(t_1 (/ (- (sqrt (- (* b b) (* c (* a 3.0)))) b) (* a 3.0))))
(if (<= t_1 -0.00019)
t_0
(if (<= t_1 -3.5e-6)
(* -0.5 (/ (/ a b) (/ a c)))
(if (<= t_1 -3.6e-8) t_0 (* -0.5 (/ c b)))))))
double code(double a, double b, double c) {
double t_0 = (sqrt(fma(b, b, (a * (c * -3.0)))) - b) / (a * 3.0);
double t_1 = (sqrt(((b * b) - (c * (a * 3.0)))) - b) / (a * 3.0);
double tmp;
if (t_1 <= -0.00019) {
tmp = t_0;
} else if (t_1 <= -3.5e-6) {
tmp = -0.5 * ((a / b) / (a / c));
} else if (t_1 <= -3.6e-8) {
tmp = t_0;
} else {
tmp = -0.5 * (c / b);
}
return tmp;
}
function code(a, b, c) t_0 = Float64(Float64(sqrt(fma(b, b, Float64(a * Float64(c * -3.0)))) - b) / Float64(a * 3.0)) t_1 = Float64(Float64(sqrt(Float64(Float64(b * b) - Float64(c * Float64(a * 3.0)))) - b) / Float64(a * 3.0)) tmp = 0.0 if (t_1 <= -0.00019) tmp = t_0; elseif (t_1 <= -3.5e-6) tmp = Float64(-0.5 * Float64(Float64(a / b) / Float64(a / c))); elseif (t_1 <= -3.6e-8) tmp = t_0; else tmp = Float64(-0.5 * Float64(c / b)); end return tmp end
code[a_, b_, c_] := Block[{t$95$0 = N[(N[(N[Sqrt[N[(b * b + N[(a * N[(c * -3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(N[(N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(c * N[(a * 3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$1, -0.00019], t$95$0, If[LessEqual[t$95$1, -3.5e-6], N[(-0.5 * N[(N[(a / b), $MachinePrecision] / N[(a / c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[t$95$1, -3.6e-8], t$95$0, N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision]]]]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{\sqrt{\mathsf{fma}\left(b, b, a \cdot \left(c \cdot -3\right)\right)} - b}{a \cdot 3}\\
t_1 := \frac{\sqrt{b \cdot b - c \cdot \left(a \cdot 3\right)} - b}{a \cdot 3}\\
\mathbf{if}\;t_1 \leq -0.00019:\\
\;\;\;\;t_0\\
\mathbf{elif}\;t_1 \leq -3.5 \cdot 10^{-6}:\\
\;\;\;\;-0.5 \cdot \frac{\frac{a}{b}}{\frac{a}{c}}\\
\mathbf{elif}\;t_1 \leq -3.6 \cdot 10^{-8}:\\
\;\;\;\;t_0\\
\mathbf{else}:\\
\;\;\;\;-0.5 \cdot \frac{c}{b}\\
\end{array}
\end{array}
(FPCore (a b c)
:precision binary64
(let* ((t_0 (/ (- (sqrt (- (* b b) (* a (* 3.0 c)))) b) (* a 3.0)))
(t_1 (/ (- (sqrt (- (* b b) (* c (* a 3.0)))) b) (* a 3.0))))
(if (<= t_1 -0.00019)
t_0
(if (<= t_1 -3.5e-6)
(* -0.5 (/ (/ a b) (/ a c)))
(if (<= t_1 -3.6e-8) t_0 (* -0.5 (/ c b)))))))
double code(double a, double b, double c) {
double t_0 = (sqrt(((b * b) - (a * (3.0 * c)))) - b) / (a * 3.0);
double t_1 = (sqrt(((b * b) - (c * (a * 3.0)))) - b) / (a * 3.0);
double tmp;
if (t_1 <= -0.00019) {
tmp = t_0;
} else if (t_1 <= -3.5e-6) {
tmp = -0.5 * ((a / b) / (a / c));
} else if (t_1 <= -3.6e-8) {
tmp = t_0;
} else {
tmp = -0.5 * (c / b);
}
return tmp;
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
real(8) :: t_0
real(8) :: t_1
real(8) :: tmp
t_0 = (sqrt(((b * b) - (a * (3.0d0 * c)))) - b) / (a * 3.0d0)
t_1 = (sqrt(((b * b) - (c * (a * 3.0d0)))) - b) / (a * 3.0d0)
if (t_1 <= (-0.00019d0)) then
tmp = t_0
else if (t_1 <= (-3.5d-6)) then
tmp = (-0.5d0) * ((a / b) / (a / c))
else if (t_1 <= (-3.6d-8)) then
tmp = t_0
else
tmp = (-0.5d0) * (c / b)
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double t_0 = (Math.sqrt(((b * b) - (a * (3.0 * c)))) - b) / (a * 3.0);
double t_1 = (Math.sqrt(((b * b) - (c * (a * 3.0)))) - b) / (a * 3.0);
double tmp;
if (t_1 <= -0.00019) {
tmp = t_0;
} else if (t_1 <= -3.5e-6) {
tmp = -0.5 * ((a / b) / (a / c));
} else if (t_1 <= -3.6e-8) {
tmp = t_0;
} else {
tmp = -0.5 * (c / b);
}
return tmp;
}
def code(a, b, c): t_0 = (math.sqrt(((b * b) - (a * (3.0 * c)))) - b) / (a * 3.0) t_1 = (math.sqrt(((b * b) - (c * (a * 3.0)))) - b) / (a * 3.0) tmp = 0 if t_1 <= -0.00019: tmp = t_0 elif t_1 <= -3.5e-6: tmp = -0.5 * ((a / b) / (a / c)) elif t_1 <= -3.6e-8: tmp = t_0 else: tmp = -0.5 * (c / b) return tmp
function code(a, b, c) t_0 = Float64(Float64(sqrt(Float64(Float64(b * b) - Float64(a * Float64(3.0 * c)))) - b) / Float64(a * 3.0)) t_1 = Float64(Float64(sqrt(Float64(Float64(b * b) - Float64(c * Float64(a * 3.0)))) - b) / Float64(a * 3.0)) tmp = 0.0 if (t_1 <= -0.00019) tmp = t_0; elseif (t_1 <= -3.5e-6) tmp = Float64(-0.5 * Float64(Float64(a / b) / Float64(a / c))); elseif (t_1 <= -3.6e-8) tmp = t_0; else tmp = Float64(-0.5 * Float64(c / b)); end return tmp end
function tmp_2 = code(a, b, c) t_0 = (sqrt(((b * b) - (a * (3.0 * c)))) - b) / (a * 3.0); t_1 = (sqrt(((b * b) - (c * (a * 3.0)))) - b) / (a * 3.0); tmp = 0.0; if (t_1 <= -0.00019) tmp = t_0; elseif (t_1 <= -3.5e-6) tmp = -0.5 * ((a / b) / (a / c)); elseif (t_1 <= -3.6e-8) tmp = t_0; else tmp = -0.5 * (c / b); end tmp_2 = tmp; end
code[a_, b_, c_] := Block[{t$95$0 = N[(N[(N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(a * N[(3.0 * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(N[(N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(c * N[(a * 3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$1, -0.00019], t$95$0, If[LessEqual[t$95$1, -3.5e-6], N[(-0.5 * N[(N[(a / b), $MachinePrecision] / N[(a / c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[t$95$1, -3.6e-8], t$95$0, N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision]]]]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{\sqrt{b \cdot b - a \cdot \left(3 \cdot c\right)} - b}{a \cdot 3}\\
t_1 := \frac{\sqrt{b \cdot b - c \cdot \left(a \cdot 3\right)} - b}{a \cdot 3}\\
\mathbf{if}\;t_1 \leq -0.00019:\\
\;\;\;\;t_0\\
\mathbf{elif}\;t_1 \leq -3.5 \cdot 10^{-6}:\\
\;\;\;\;-0.5 \cdot \frac{\frac{a}{b}}{\frac{a}{c}}\\
\mathbf{elif}\;t_1 \leq -3.6 \cdot 10^{-8}:\\
\;\;\;\;t_0\\
\mathbf{else}:\\
\;\;\;\;-0.5 \cdot \frac{c}{b}\\
\end{array}
\end{array}
(FPCore (a b c) :precision binary64 (if (<= (/ (- (sqrt (- (* b b) (* c (* a 3.0)))) b) (* a 3.0)) -0.00035) (/ (- (sqrt (fma b b (* a (* c -3.0)))) b) (* a 3.0)) (+ (* -0.5 (/ c b)) (* -0.375 (/ (* a (pow c 2.0)) (pow b 3.0))))))
double code(double a, double b, double c) {
double tmp;
if (((sqrt(((b * b) - (c * (a * 3.0)))) - b) / (a * 3.0)) <= -0.00035) {
tmp = (sqrt(fma(b, b, (a * (c * -3.0)))) - b) / (a * 3.0);
} else {
tmp = (-0.5 * (c / b)) + (-0.375 * ((a * pow(c, 2.0)) / pow(b, 3.0)));
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (Float64(Float64(sqrt(Float64(Float64(b * b) - Float64(c * Float64(a * 3.0)))) - b) / Float64(a * 3.0)) <= -0.00035) tmp = Float64(Float64(sqrt(fma(b, b, Float64(a * Float64(c * -3.0)))) - b) / Float64(a * 3.0)); else tmp = Float64(Float64(-0.5 * Float64(c / b)) + Float64(-0.375 * Float64(Float64(a * (c ^ 2.0)) / (b ^ 3.0)))); end return tmp end
code[a_, b_, c_] := If[LessEqual[N[(N[(N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(c * N[(a * 3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision], -0.00035], N[(N[(N[Sqrt[N[(b * b + N[(a * N[(c * -3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision], N[(N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision] + N[(-0.375 * N[(N[(a * N[Power[c, 2.0], $MachinePrecision]), $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\frac{\sqrt{b \cdot b - c \cdot \left(a \cdot 3\right)} - b}{a \cdot 3} \leq -0.00035:\\
\;\;\;\;\frac{\sqrt{\mathsf{fma}\left(b, b, a \cdot \left(c \cdot -3\right)\right)} - b}{a \cdot 3}\\
\mathbf{else}:\\
\;\;\;\;-0.5 \cdot \frac{c}{b} + -0.375 \cdot \frac{a \cdot {c}^{2}}{{b}^{3}}\\
\end{array}
\end{array}
(FPCore (a b c) :precision binary64 (* -0.5 (/ c b)))
double code(double a, double b, double c) {
return -0.5 * (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 = (-0.5d0) * (c / b)
end function
public static double code(double a, double b, double c) {
return -0.5 * (c / b);
}
def code(a, b, c): return -0.5 * (c / b)
function code(a, b, c) return Float64(-0.5 * Float64(c / b)) end
function tmp = code(a, b, c) tmp = -0.5 * (c / b); end
code[a_, b_, c_] := N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
-0.5 \cdot \frac{c}{b}
\end{array}
(FPCore (a b c) :precision binary64 0.0)
double code(double a, double b, double c) {
return 0.0;
}
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
end function
public static double code(double a, double b, double c) {
return 0.0;
}
def code(a, b, c): return 0.0
function code(a, b, c) return 0.0 end
function tmp = code(a, b, c) tmp = 0.0; end
code[a_, b_, c_] := 0.0
\begin{array}{l}
\\
0
\end{array}
herbie shell --seed 2023348
(FPCore (a b c)
:name "Cubic critical, narrow range"
:precision binary64
:pre (and (and (and (< 1.0536712127723509e-8 a) (< a 94906265.62425156)) (and (< 1.0536712127723509e-8 b) (< b 94906265.62425156))) (and (< 1.0536712127723509e-8 c) (< c 94906265.62425156)))
(/ (+ (- b) (sqrt (- (* b b) (* (* 3.0 a) c)))) (* 3.0 a)))