
(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 (* b (* b (* b b)))))
(/
(fma
(/ (* (* c (* c c)) (* a -0.5625)) t_0)
a
(fma
c
-0.5
(fma
a
(/ (* c c) (* (* b b) -2.6666666666666665))
(/
(*
(* a (* (* a a) -0.16666666666666666))
(* c (* c (* c (* c 6.328125)))))
(* b (* b t_0))))))
b)))
double code(double a, double b, double c) {
double t_0 = b * (b * (b * b));
return fma((((c * (c * c)) * (a * -0.5625)) / t_0), a, fma(c, -0.5, fma(a, ((c * c) / ((b * b) * -2.6666666666666665)), (((a * ((a * a) * -0.16666666666666666)) * (c * (c * (c * (c * 6.328125))))) / (b * (b * t_0)))))) / b;
}
function code(a, b, c) t_0 = Float64(b * Float64(b * Float64(b * b))) return Float64(fma(Float64(Float64(Float64(c * Float64(c * c)) * Float64(a * -0.5625)) / t_0), a, fma(c, -0.5, fma(a, Float64(Float64(c * c) / Float64(Float64(b * b) * -2.6666666666666665)), Float64(Float64(Float64(a * Float64(Float64(a * a) * -0.16666666666666666)) * Float64(c * Float64(c * Float64(c * Float64(c * 6.328125))))) / Float64(b * Float64(b * t_0)))))) / b) end
code[a_, b_, c_] := Block[{t$95$0 = N[(b * N[(b * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, N[(N[(N[(N[(N[(c * N[(c * c), $MachinePrecision]), $MachinePrecision] * N[(a * -0.5625), $MachinePrecision]), $MachinePrecision] / t$95$0), $MachinePrecision] * a + N[(c * -0.5 + N[(a * N[(N[(c * c), $MachinePrecision] / N[(N[(b * b), $MachinePrecision] * -2.6666666666666665), $MachinePrecision]), $MachinePrecision] + N[(N[(N[(a * N[(N[(a * a), $MachinePrecision] * -0.16666666666666666), $MachinePrecision]), $MachinePrecision] * N[(c * N[(c * N[(c * N[(c * 6.328125), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(b * N[(b * t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := b \cdot \left(b \cdot \left(b \cdot b\right)\right)\\
\frac{\mathsf{fma}\left(\frac{\left(c \cdot \left(c \cdot c\right)\right) \cdot \left(a \cdot -0.5625\right)}{t\_0}, a, \mathsf{fma}\left(c, -0.5, \mathsf{fma}\left(a, \frac{c \cdot c}{\left(b \cdot b\right) \cdot -2.6666666666666665}, \frac{\left(a \cdot \left(\left(a \cdot a\right) \cdot -0.16666666666666666\right)\right) \cdot \left(c \cdot \left(c \cdot \left(c \cdot \left(c \cdot 6.328125\right)\right)\right)\right)}{b \cdot \left(b \cdot t\_0\right)}\right)\right)\right)}{b}
\end{array}
\end{array}
Initial program 31.0%
Taylor expanded in b around inf
Applied rewrites96.9%
Applied rewrites96.9%
Applied rewrites96.9%
Final simplification96.9%
(FPCore (a b c)
:precision binary64
(let* ((t_0 (* b (* b (* b b)))))
(/
(fma
c
-0.5
(fma
a
(/ (* (* c (* c c)) (* a -0.5625)) t_0)
(fma
a
(/ (* c c) (* (* b b) -2.6666666666666665))
(/
(*
(* a (* (* a a) -0.16666666666666666))
(* c (* c (* c (* c 6.328125)))))
(* b (* b t_0))))))
b)))
double code(double a, double b, double c) {
double t_0 = b * (b * (b * b));
return fma(c, -0.5, fma(a, (((c * (c * c)) * (a * -0.5625)) / t_0), fma(a, ((c * c) / ((b * b) * -2.6666666666666665)), (((a * ((a * a) * -0.16666666666666666)) * (c * (c * (c * (c * 6.328125))))) / (b * (b * t_0)))))) / b;
}
function code(a, b, c) t_0 = Float64(b * Float64(b * Float64(b * b))) return Float64(fma(c, -0.5, fma(a, Float64(Float64(Float64(c * Float64(c * c)) * Float64(a * -0.5625)) / t_0), fma(a, Float64(Float64(c * c) / Float64(Float64(b * b) * -2.6666666666666665)), Float64(Float64(Float64(a * Float64(Float64(a * a) * -0.16666666666666666)) * Float64(c * Float64(c * Float64(c * Float64(c * 6.328125))))) / Float64(b * Float64(b * t_0)))))) / b) end
code[a_, b_, c_] := Block[{t$95$0 = N[(b * N[(b * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, N[(N[(c * -0.5 + N[(a * N[(N[(N[(c * N[(c * c), $MachinePrecision]), $MachinePrecision] * N[(a * -0.5625), $MachinePrecision]), $MachinePrecision] / t$95$0), $MachinePrecision] + N[(a * N[(N[(c * c), $MachinePrecision] / N[(N[(b * b), $MachinePrecision] * -2.6666666666666665), $MachinePrecision]), $MachinePrecision] + N[(N[(N[(a * N[(N[(a * a), $MachinePrecision] * -0.16666666666666666), $MachinePrecision]), $MachinePrecision] * N[(c * N[(c * N[(c * N[(c * 6.328125), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(b * N[(b * t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := b \cdot \left(b \cdot \left(b \cdot b\right)\right)\\
\frac{\mathsf{fma}\left(c, -0.5, \mathsf{fma}\left(a, \frac{\left(c \cdot \left(c \cdot c\right)\right) \cdot \left(a \cdot -0.5625\right)}{t\_0}, \mathsf{fma}\left(a, \frac{c \cdot c}{\left(b \cdot b\right) \cdot -2.6666666666666665}, \frac{\left(a \cdot \left(\left(a \cdot a\right) \cdot -0.16666666666666666\right)\right) \cdot \left(c \cdot \left(c \cdot \left(c \cdot \left(c \cdot 6.328125\right)\right)\right)\right)}{b \cdot \left(b \cdot t\_0\right)}\right)\right)\right)}{b}
\end{array}
\end{array}
Initial program 31.5%
Taylor expanded in b around inf
Applied rewrites95.6%
Applied rewrites95.6%
Applied rewrites95.6%
Final simplification95.6%
herbie shell --seed 2024219
(FPCore (a b c)
:name "Cubic critical, 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) (* (* 3.0 a) c)))) (* 3.0 a)))