
(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 4 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 (acos (/ g (- h))))
(t_1 (* 0.1111111111111111 (pow t_0 2.0)))
(t_2 (fma 0.3333333333333333 t_0 (* -0.6666666666666666 PI))))
(fma
2.0
(* (sin (/ t_1 t_2)) (sin (/ (* 0.4444444444444444 (* PI PI)) t_2)))
(+
(cos (fma 0.3333333333333333 t_0 (* 0.6666666666666666 PI)))
(cos (/ (fma PI (* 0.4444444444444444 PI) t_1) t_2))))))
double code(double g, double h) {
double t_0 = acos((g / -h));
double t_1 = 0.1111111111111111 * pow(t_0, 2.0);
double t_2 = fma(0.3333333333333333, t_0, (-0.6666666666666666 * ((double) M_PI)));
return fma(2.0, (sin((t_1 / t_2)) * sin(((0.4444444444444444 * (((double) M_PI) * ((double) M_PI))) / t_2))), (cos(fma(0.3333333333333333, t_0, (0.6666666666666666 * ((double) M_PI)))) + cos((fma(((double) M_PI), (0.4444444444444444 * ((double) M_PI)), t_1) / t_2))));
}
function code(g, h) t_0 = acos(Float64(g / Float64(-h))) t_1 = Float64(0.1111111111111111 * (t_0 ^ 2.0)) t_2 = fma(0.3333333333333333, t_0, Float64(-0.6666666666666666 * pi)) return fma(2.0, Float64(sin(Float64(t_1 / t_2)) * sin(Float64(Float64(0.4444444444444444 * Float64(pi * pi)) / t_2))), Float64(cos(fma(0.3333333333333333, t_0, Float64(0.6666666666666666 * pi))) + cos(Float64(fma(pi, Float64(0.4444444444444444 * pi), t_1) / t_2)))) end
code[g_, h_] := Block[{t$95$0 = N[ArcCos[N[(g / (-h)), $MachinePrecision]], $MachinePrecision]}, Block[{t$95$1 = N[(0.1111111111111111 * N[Power[t$95$0, 2.0], $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(0.3333333333333333 * t$95$0 + N[(-0.6666666666666666 * Pi), $MachinePrecision]), $MachinePrecision]}, N[(2.0 * N[(N[Sin[N[(t$95$1 / t$95$2), $MachinePrecision]], $MachinePrecision] * N[Sin[N[(N[(0.4444444444444444 * N[(Pi * Pi), $MachinePrecision]), $MachinePrecision] / t$95$2), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] + N[(N[Cos[N[(0.3333333333333333 * t$95$0 + N[(0.6666666666666666 * Pi), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + N[Cos[N[(N[(Pi * N[(0.4444444444444444 * Pi), $MachinePrecision] + t$95$1), $MachinePrecision] / t$95$2), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \cos^{-1} \left(\frac{g}{-h}\right)\\
t_1 := 0.1111111111111111 \cdot {t\_0}^{2}\\
t_2 := \mathsf{fma}\left(0.3333333333333333, t\_0, -0.6666666666666666 \cdot \pi\right)\\
\mathsf{fma}\left(2, \sin \left(\frac{t\_1}{t\_2}\right) \cdot \sin \left(\frac{0.4444444444444444 \cdot \left(\pi \cdot \pi\right)}{t\_2}\right), \cos \left(\mathsf{fma}\left(0.3333333333333333, t\_0, 0.6666666666666666 \cdot \pi\right)\right) + \cos \left(\frac{\mathsf{fma}\left(\pi, 0.4444444444444444 \cdot \pi, t\_1\right)}{t\_2}\right)\right)
\end{array}
\end{array}
Initial program 98.4%
lift-+.f64N/A
lift-/.f64N/A
div-invN/A
lift-*.f64N/A
*-commutativeN/A
associate-*l*N/A
lower-fma.f64N/A
metadata-evalN/A
metadata-eval98.5
lift-/.f64N/A
div-invN/A
lower-*.f64N/A
lift-/.f64N/A
frac-2negN/A
lift-neg.f64N/A
remove-double-negN/A
lower-/.f64N/A
lower-neg.f64N/A
metadata-eval98.5
Applied rewrites98.5%
lift-cos.f64N/A
lift-fma.f64N/A
lift-*.f64N/A
+-commutativeN/A
flip-+N/A
div-subN/A
cos-diffN/A
Applied rewrites98.4%
Applied rewrites100.0%
Taylor expanded in g around 0
Applied rewrites100.0%
Final simplification100.0%
(FPCore (g h) :precision binary64 (* 2.0 (cos (/ (fma (acos (/ g (- h))) (/ -1.5 PI) -3.0) (* (/ -1.5 PI) 3.0)))))
double code(double g, double h) {
return 2.0 * cos((fma(acos((g / -h)), (-1.5 / ((double) M_PI)), -3.0) / ((-1.5 / ((double) M_PI)) * 3.0)));
}
function code(g, h) return Float64(2.0 * cos(Float64(fma(acos(Float64(g / Float64(-h))), Float64(-1.5 / pi), -3.0) / Float64(Float64(-1.5 / pi) * 3.0)))) end
code[g_, h_] := N[(2.0 * N[Cos[N[(N[(N[ArcCos[N[(g / (-h)), $MachinePrecision]], $MachinePrecision] * N[(-1.5 / Pi), $MachinePrecision] + -3.0), $MachinePrecision] / N[(N[(-1.5 / Pi), $MachinePrecision] * 3.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
2 \cdot \cos \left(\frac{\mathsf{fma}\left(\cos^{-1} \left(\frac{g}{-h}\right), \frac{-1.5}{\pi}, -3\right)}{\frac{-1.5}{\pi} \cdot 3}\right)
\end{array}
Initial program 98.4%
lift-+.f64N/A
+-commutativeN/A
lift-/.f64N/A
lift-/.f64N/A
clear-numN/A
frac-2negN/A
metadata-evalN/A
frac-addN/A
lower-/.f64N/A
Applied rewrites98.5%
Final simplification98.5%
(FPCore (g h) :precision binary64 (* 2.0 (cos (/ (fma (acos (/ g (- h))) -3.0 (* PI -6.0)) -9.0))))
double code(double g, double h) {
return 2.0 * cos((fma(acos((g / -h)), -3.0, (((double) M_PI) * -6.0)) / -9.0));
}
function code(g, h) return Float64(2.0 * cos(Float64(fma(acos(Float64(g / Float64(-h))), -3.0, Float64(pi * -6.0)) / -9.0))) end
code[g_, h_] := N[(2.0 * N[Cos[N[(N[(N[ArcCos[N[(g / (-h)), $MachinePrecision]], $MachinePrecision] * -3.0 + N[(Pi * -6.0), $MachinePrecision]), $MachinePrecision] / -9.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
2 \cdot \cos \left(\frac{\mathsf{fma}\left(\cos^{-1} \left(\frac{g}{-h}\right), -3, \pi \cdot -6\right)}{-9}\right)
\end{array}
Initial program 98.4%
lift-+.f64N/A
+-commutativeN/A
lift-/.f64N/A
lift-/.f64N/A
frac-2negN/A
frac-addN/A
lower-/.f64N/A
Applied rewrites98.5%
(FPCore (g h) :precision binary64 (* 2.0 (cos (fma PI 0.6666666666666666 (* 0.3333333333333333 (acos (/ g (- h))))))))
double code(double g, double h) {
return 2.0 * cos(fma(((double) M_PI), 0.6666666666666666, (0.3333333333333333 * acos((g / -h)))));
}
function code(g, h) return Float64(2.0 * cos(fma(pi, 0.6666666666666666, Float64(0.3333333333333333 * acos(Float64(g / Float64(-h))))))) end
code[g_, h_] := N[(2.0 * N[Cos[N[(Pi * 0.6666666666666666 + N[(0.3333333333333333 * N[ArcCos[N[(g / (-h)), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
2 \cdot \cos \left(\mathsf{fma}\left(\pi, 0.6666666666666666, 0.3333333333333333 \cdot \cos^{-1} \left(\frac{g}{-h}\right)\right)\right)
\end{array}
Initial program 98.4%
lift-+.f64N/A
lift-/.f64N/A
div-invN/A
lift-*.f64N/A
*-commutativeN/A
associate-*l*N/A
lower-fma.f64N/A
metadata-evalN/A
metadata-eval98.5
lift-/.f64N/A
div-invN/A
lower-*.f64N/A
lift-/.f64N/A
frac-2negN/A
lift-neg.f64N/A
remove-double-negN/A
lower-/.f64N/A
lower-neg.f64N/A
metadata-eval98.5
Applied rewrites98.5%
Final simplification98.5%
herbie shell --seed 2024222
(FPCore (g h)
:name "2-ancestry mixing, negative discriminant"
:precision binary64
(* 2.0 (cos (+ (/ (* 2.0 PI) 3.0) (/ (acos (/ (- g) h)) 3.0)))))