
(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 8 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 (/ (/ (* c (* a 3.0)) (- (- b) (sqrt (- (pow b 2.0) (* a (* 3.0 c)))))) (* a 3.0)))
double code(double a, double b, double c) {
return ((c * (a * 3.0)) / (-b - sqrt((pow(b, 2.0) - (a * (3.0 * c)))))) / (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
code = ((c * (a * 3.0d0)) / (-b - sqrt(((b ** 2.0d0) - (a * (3.0d0 * c)))))) / (a * 3.0d0)
end function
public static double code(double a, double b, double c) {
return ((c * (a * 3.0)) / (-b - Math.sqrt((Math.pow(b, 2.0) - (a * (3.0 * c)))))) / (a * 3.0);
}
def code(a, b, c): return ((c * (a * 3.0)) / (-b - math.sqrt((math.pow(b, 2.0) - (a * (3.0 * c)))))) / (a * 3.0)
function code(a, b, c) return Float64(Float64(Float64(c * Float64(a * 3.0)) / Float64(Float64(-b) - sqrt(Float64((b ^ 2.0) - Float64(a * Float64(3.0 * c)))))) / Float64(a * 3.0)) end
function tmp = code(a, b, c) tmp = ((c * (a * 3.0)) / (-b - sqrt(((b ^ 2.0) - (a * (3.0 * c)))))) / (a * 3.0); end
code[a_, b_, c_] := N[(N[(N[(c * N[(a * 3.0), $MachinePrecision]), $MachinePrecision] / N[((-b) - N[Sqrt[N[(N[Power[b, 2.0], $MachinePrecision] - N[(a * N[(3.0 * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{c \cdot \left(a \cdot 3\right)}{\left(-b\right) - \sqrt{{b}^{2} - a \cdot \left(3 \cdot c\right)}}}{a \cdot 3}
\end{array}
(FPCore (a b c) :precision binary64 (let* ((t_0 (/ (- (sqrt (- (* b b) (* c (* a 3.0)))) b) (* a 3.0)))) (if (<= t_0 -0.15) t_0 (/ 1.0 (+ (* -2.0 (/ b c)) (* 1.5 (/ a b)))))))
double code(double a, double b, double c) {
double t_0 = (sqrt(((b * b) - (c * (a * 3.0)))) - b) / (a * 3.0);
double tmp;
if (t_0 <= -0.15) {
tmp = t_0;
} else {
tmp = 1.0 / ((-2.0 * (b / c)) + (1.5 * (a / 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) :: tmp
t_0 = (sqrt(((b * b) - (c * (a * 3.0d0)))) - b) / (a * 3.0d0)
if (t_0 <= (-0.15d0)) then
tmp = t_0
else
tmp = 1.0d0 / (((-2.0d0) * (b / c)) + (1.5d0 * (a / b)))
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double t_0 = (Math.sqrt(((b * b) - (c * (a * 3.0)))) - b) / (a * 3.0);
double tmp;
if (t_0 <= -0.15) {
tmp = t_0;
} else {
tmp = 1.0 / ((-2.0 * (b / c)) + (1.5 * (a / b)));
}
return tmp;
}
def code(a, b, c): t_0 = (math.sqrt(((b * b) - (c * (a * 3.0)))) - b) / (a * 3.0) tmp = 0 if t_0 <= -0.15: tmp = t_0 else: tmp = 1.0 / ((-2.0 * (b / c)) + (1.5 * (a / b))) return tmp
function code(a, b, c) t_0 = Float64(Float64(sqrt(Float64(Float64(b * b) - Float64(c * Float64(a * 3.0)))) - b) / Float64(a * 3.0)) tmp = 0.0 if (t_0 <= -0.15) tmp = t_0; else tmp = Float64(1.0 / Float64(Float64(-2.0 * Float64(b / c)) + Float64(1.5 * Float64(a / b)))); end return tmp end
function tmp_2 = code(a, b, c) t_0 = (sqrt(((b * b) - (c * (a * 3.0)))) - b) / (a * 3.0); tmp = 0.0; if (t_0 <= -0.15) tmp = t_0; else tmp = 1.0 / ((-2.0 * (b / c)) + (1.5 * (a / b))); end tmp_2 = tmp; end
code[a_, b_, c_] := Block[{t$95$0 = 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$0, -0.15], t$95$0, N[(1.0 / N[(N[(-2.0 * N[(b / c), $MachinePrecision]), $MachinePrecision] + N[(1.5 * N[(a / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{\sqrt{b \cdot b - c \cdot \left(a \cdot 3\right)} - b}{a \cdot 3}\\
\mathbf{if}\;t_0 \leq -0.15:\\
\;\;\;\;t_0\\
\mathbf{else}:\\
\;\;\;\;\frac{1}{-2 \cdot \frac{b}{c} + 1.5 \cdot \frac{a}{b}}\\
\end{array}
\end{array}
(FPCore (a b c) :precision binary64 (/ (/ (* 3.0 (* a c)) (- (- b) (sqrt (- (pow b 2.0) (* a (* 3.0 c)))))) (* a 3.0)))
double code(double a, double b, double c) {
return ((3.0 * (a * c)) / (-b - sqrt((pow(b, 2.0) - (a * (3.0 * c)))))) / (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
code = ((3.0d0 * (a * c)) / (-b - sqrt(((b ** 2.0d0) - (a * (3.0d0 * c)))))) / (a * 3.0d0)
end function
public static double code(double a, double b, double c) {
return ((3.0 * (a * c)) / (-b - Math.sqrt((Math.pow(b, 2.0) - (a * (3.0 * c)))))) / (a * 3.0);
}
def code(a, b, c): return ((3.0 * (a * c)) / (-b - math.sqrt((math.pow(b, 2.0) - (a * (3.0 * c)))))) / (a * 3.0)
function code(a, b, c) return Float64(Float64(Float64(3.0 * Float64(a * c)) / Float64(Float64(-b) - sqrt(Float64((b ^ 2.0) - Float64(a * Float64(3.0 * c)))))) / Float64(a * 3.0)) end
function tmp = code(a, b, c) tmp = ((3.0 * (a * c)) / (-b - sqrt(((b ^ 2.0) - (a * (3.0 * c)))))) / (a * 3.0); end
code[a_, b_, c_] := N[(N[(N[(3.0 * N[(a * c), $MachinePrecision]), $MachinePrecision] / N[((-b) - N[Sqrt[N[(N[Power[b, 2.0], $MachinePrecision] - N[(a * N[(3.0 * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{3 \cdot \left(a \cdot c\right)}{\left(-b\right) - \sqrt{{b}^{2} - a \cdot \left(3 \cdot c\right)}}}{a \cdot 3}
\end{array}
(FPCore (a b c) :precision binary64 (let* ((t_0 (* a (* 3.0 c)))) (/ (/ 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 (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 = (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 (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 (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(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 = (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[(t$95$0 / 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{t_0}{\left(-b\right) - \sqrt{{b}^{2} - t_0}}}{a \cdot 3}
\end{array}
\end{array}
(FPCore (a b c) :precision binary64 (if (<= b 3.35) (/ (- (sqrt (- (* b b) (* a (* 3.0 c)))) b) (* a 3.0)) (/ 1.0 (+ (* -2.0 (/ b c)) (* 1.5 (/ a b))))))
double code(double a, double b, double c) {
double tmp;
if (b <= 3.35) {
tmp = (sqrt(((b * b) - (a * (3.0 * c)))) - b) / (a * 3.0);
} else {
tmp = 1.0 / ((-2.0 * (b / c)) + (1.5 * (a / 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) :: tmp
if (b <= 3.35d0) then
tmp = (sqrt(((b * b) - (a * (3.0d0 * c)))) - b) / (a * 3.0d0)
else
tmp = 1.0d0 / (((-2.0d0) * (b / c)) + (1.5d0 * (a / b)))
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double tmp;
if (b <= 3.35) {
tmp = (Math.sqrt(((b * b) - (a * (3.0 * c)))) - b) / (a * 3.0);
} else {
tmp = 1.0 / ((-2.0 * (b / c)) + (1.5 * (a / b)));
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= 3.35: tmp = (math.sqrt(((b * b) - (a * (3.0 * c)))) - b) / (a * 3.0) else: tmp = 1.0 / ((-2.0 * (b / c)) + (1.5 * (a / b))) return tmp
function code(a, b, c) tmp = 0.0 if (b <= 3.35) tmp = Float64(Float64(sqrt(Float64(Float64(b * b) - Float64(a * Float64(3.0 * c)))) - b) / Float64(a * 3.0)); else tmp = Float64(1.0 / Float64(Float64(-2.0 * Float64(b / c)) + Float64(1.5 * Float64(a / b)))); end return tmp end
function tmp_2 = code(a, b, c) tmp = 0.0; if (b <= 3.35) tmp = (sqrt(((b * b) - (a * (3.0 * c)))) - b) / (a * 3.0); else tmp = 1.0 / ((-2.0 * (b / c)) + (1.5 * (a / b))); end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, 3.35], 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], N[(1.0 / N[(N[(-2.0 * N[(b / c), $MachinePrecision]), $MachinePrecision] + N[(1.5 * N[(a / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq 3.35:\\
\;\;\;\;\frac{\sqrt{b \cdot b - a \cdot \left(3 \cdot c\right)} - b}{a \cdot 3}\\
\mathbf{else}:\\
\;\;\;\;\frac{1}{-2 \cdot \frac{b}{c} + 1.5 \cdot \frac{a}{b}}\\
\end{array}
\end{array}
(FPCore (a b c) :precision binary64 (/ 1.0 (+ (* -2.0 (/ b c)) (* 1.5 (/ a b)))))
double code(double a, double b, double c) {
return 1.0 / ((-2.0 * (b / c)) + (1.5 * (a / b)));
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = 1.0d0 / (((-2.0d0) * (b / c)) + (1.5d0 * (a / b)))
end function
public static double code(double a, double b, double c) {
return 1.0 / ((-2.0 * (b / c)) + (1.5 * (a / b)));
}
def code(a, b, c): return 1.0 / ((-2.0 * (b / c)) + (1.5 * (a / b)))
function code(a, b, c) return Float64(1.0 / Float64(Float64(-2.0 * Float64(b / c)) + Float64(1.5 * Float64(a / b)))) end
function tmp = code(a, b, c) tmp = 1.0 / ((-2.0 * (b / c)) + (1.5 * (a / b))); end
code[a_, b_, c_] := N[(1.0 / N[(N[(-2.0 * N[(b / c), $MachinePrecision]), $MachinePrecision] + N[(1.5 * N[(a / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{-2 \cdot \frac{b}{c} + 1.5 \cdot \frac{a}{b}}
\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 a))
double code(double a, double b, double c) {
return 0.0 / a;
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = 0.0d0 / a
end function
public static double code(double a, double b, double c) {
return 0.0 / a;
}
def code(a, b, c): return 0.0 / a
function code(a, b, c) return Float64(0.0 / a) end
function tmp = code(a, b, c) tmp = 0.0 / a; end
code[a_, b_, c_] := N[(0.0 / a), $MachinePrecision]
\begin{array}{l}
\\
\frac{0}{a}
\end{array}
herbie shell --seed 2023350
(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)))