
(FPCore (g h) :precision binary64 (* 2.0 (cos (+ (/ (* 2.0 PI) 3.0) (/ (acos (/ (- g) h)) 3.0)))))
double code(double g, double h) {
return 2.0 * cos((((2.0 * ((double) M_PI)) / 3.0) + (acos((-g / h)) / 3.0)));
}
public static double code(double g, double h) {
return 2.0 * Math.cos((((2.0 * Math.PI) / 3.0) + (Math.acos((-g / h)) / 3.0)));
}
def code(g, h): return 2.0 * math.cos((((2.0 * math.pi) / 3.0) + (math.acos((-g / h)) / 3.0)))
function code(g, h) return Float64(2.0 * cos(Float64(Float64(Float64(2.0 * pi) / 3.0) + Float64(acos(Float64(Float64(-g) / h)) / 3.0)))) end
function tmp = code(g, h) tmp = 2.0 * cos((((2.0 * pi) / 3.0) + (acos((-g / h)) / 3.0))); end
code[g_, h_] := N[(2.0 * N[Cos[N[(N[(N[(2.0 * Pi), $MachinePrecision] / 3.0), $MachinePrecision] + N[(N[ArcCos[N[((-g) / h), $MachinePrecision]], $MachinePrecision] / 3.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
2 \cdot \cos \left(\frac{2 \cdot \pi}{3} + \frac{\cos^{-1} \left(\frac{-g}{h}\right)}{3}\right)
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 6 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (g h) :precision binary64 (* 2.0 (cos (+ (/ (* 2.0 PI) 3.0) (/ (acos (/ (- g) h)) 3.0)))))
double code(double g, double h) {
return 2.0 * cos((((2.0 * ((double) M_PI)) / 3.0) + (acos((-g / h)) / 3.0)));
}
public static double code(double g, double h) {
return 2.0 * Math.cos((((2.0 * Math.PI) / 3.0) + (Math.acos((-g / h)) / 3.0)));
}
def code(g, h): return 2.0 * math.cos((((2.0 * math.pi) / 3.0) + (math.acos((-g / h)) / 3.0)))
function code(g, h) return Float64(2.0 * cos(Float64(Float64(Float64(2.0 * pi) / 3.0) + Float64(acos(Float64(Float64(-g) / h)) / 3.0)))) end
function tmp = code(g, h) tmp = 2.0 * cos((((2.0 * pi) / 3.0) + (acos((-g / h)) / 3.0))); end
code[g_, h_] := N[(2.0 * N[Cos[N[(N[(N[(2.0 * Pi), $MachinePrecision] / 3.0), $MachinePrecision] + N[(N[ArcCos[N[((-g) / h), $MachinePrecision]], $MachinePrecision] / 3.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
2 \cdot \cos \left(\frac{2 \cdot \pi}{3} + \frac{\cos^{-1} \left(\frac{-g}{h}\right)}{3}\right)
\end{array}
(FPCore (g h)
:precision binary64
(let* ((t_0 (* 0.3333333333333333 (acos (/ g (- h))))))
(*
(fma (* (sqrt 3.0) -0.8125) (sin t_0) (* -0.8125 (cos t_0)))
1.2307692307692308)))
double code(double g, double h) {
double t_0 = 0.3333333333333333 * acos((g / -h));
return fma((sqrt(3.0) * -0.8125), sin(t_0), (-0.8125 * cos(t_0))) * 1.2307692307692308;
}
function code(g, h) t_0 = Float64(0.3333333333333333 * acos(Float64(g / Float64(-h)))) return Float64(fma(Float64(sqrt(3.0) * -0.8125), sin(t_0), Float64(-0.8125 * cos(t_0))) * 1.2307692307692308) end
code[g_, h_] := Block[{t$95$0 = N[(0.3333333333333333 * N[ArcCos[N[(g / (-h)), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]}, N[(N[(N[(N[Sqrt[3.0], $MachinePrecision] * -0.8125), $MachinePrecision] * N[Sin[t$95$0], $MachinePrecision] + N[(-0.8125 * N[Cos[t$95$0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * 1.2307692307692308), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := 0.3333333333333333 \cdot \cos^{-1} \left(\frac{g}{-h}\right)\\
\mathsf{fma}\left(\sqrt{3} \cdot -0.8125, \sin t\_0, -0.8125 \cdot \cos t\_0\right) \cdot 1.2307692307692308
\end{array}
\end{array}
Initial program 98.4%
Applied rewrites98.4%
Applied rewrites99.9%
lift-fma.f64N/A
+-commutativeN/A
Applied rewrites99.9%
lift-*.f64N/A
*-commutativeN/A
lift-/.f64N/A
div-invN/A
associate-*l*N/A
metadata-evalN/A
metadata-evalN/A
lower-*.f64100.0
Applied rewrites100.0%
Final simplification100.0%
(FPCore (g h) :precision binary64 (let* ((t_0 (* 0.3333333333333333 (acos (/ g (- h)))))) (* 1.2307692307692308 (* -0.8125 (fma (sin t_0) (sqrt 3.0) (cos t_0))))))
double code(double g, double h) {
double t_0 = 0.3333333333333333 * acos((g / -h));
return 1.2307692307692308 * (-0.8125 * fma(sin(t_0), sqrt(3.0), cos(t_0)));
}
function code(g, h) t_0 = Float64(0.3333333333333333 * acos(Float64(g / Float64(-h)))) return Float64(1.2307692307692308 * Float64(-0.8125 * fma(sin(t_0), sqrt(3.0), cos(t_0)))) end
code[g_, h_] := Block[{t$95$0 = N[(0.3333333333333333 * N[ArcCos[N[(g / (-h)), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]}, N[(1.2307692307692308 * N[(-0.8125 * N[(N[Sin[t$95$0], $MachinePrecision] * N[Sqrt[3.0], $MachinePrecision] + N[Cos[t$95$0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := 0.3333333333333333 \cdot \cos^{-1} \left(\frac{g}{-h}\right)\\
1.2307692307692308 \cdot \left(-0.8125 \cdot \mathsf{fma}\left(\sin t\_0, \sqrt{3}, \cos t\_0\right)\right)
\end{array}
\end{array}
Initial program 98.4%
Applied rewrites98.4%
Applied rewrites100.0%
Applied rewrites100.0%
Taylor expanded in g around 0
distribute-lft-outN/A
lower-*.f64N/A
+-commutativeN/A
lower-fma.f64N/A
lower-sin.f64N/A
lower-*.f64N/A
lower-acos.f64N/A
mul-1-negN/A
lower-neg.f64N/A
lower-/.f64N/A
lower-sqrt.f64N/A
lower-cos.f64N/A
lower-*.f64N/A
lower-acos.f64N/A
mul-1-negN/A
lower-neg.f64N/A
lower-/.f64100.0
Applied rewrites100.0%
Final simplification100.0%
herbie shell --seed 2024226
(FPCore (g h)
:name "2-ancestry mixing, negative discriminant"
:precision binary64
(* 2.0 (cos (+ (/ (* 2.0 PI) 3.0) (/ (acos (/ (- g) h)) 3.0)))))