
(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}
Herbie found 2 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 (* (sin (fma (acos (/ (- g) h)) -0.3333333333333333 (* PI -0.16666666666666666))) 2.0))
double code(double g, double h) {
return sin(fma(acos((-g / h)), -0.3333333333333333, (((double) M_PI) * -0.16666666666666666))) * 2.0;
}
function code(g, h) return Float64(sin(fma(acos(Float64(Float64(-g) / h)), -0.3333333333333333, Float64(pi * -0.16666666666666666))) * 2.0) end
code[g_, h_] := N[(N[Sin[N[(N[ArcCos[N[((-g) / h), $MachinePrecision]], $MachinePrecision] * -0.3333333333333333 + N[(Pi * -0.16666666666666666), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * 2.0), $MachinePrecision]
\begin{array}{l}
\\
\sin \left(\mathsf{fma}\left(\cos^{-1} \left(\frac{-g}{h}\right), -0.3333333333333333, \pi \cdot -0.16666666666666666\right)\right) \cdot 2
\end{array}
Initial program 98.5%
Applied rewrites98.5%
lift-*.f64N/A
*-commutativeN/A
lower-*.f6498.5
Applied rewrites99.9%
lift-PI.f64N/A
lift-fma.f64N/A
lift-PI.f64N/A
lift-*.f64N/A
distribute-lft-outN/A
lower-*.f64N/A
lift-PI.f64N/A
metadata-eval100.0
Applied rewrites100.0%
(FPCore (g h) :precision binary64 (* (sin (fma 0.3333333333333333 (acos (/ (- g) h)) (* PI 1.1666666666666667))) 2.0))
double code(double g, double h) {
return sin(fma(0.3333333333333333, acos((-g / h)), (((double) M_PI) * 1.1666666666666667))) * 2.0;
}
function code(g, h) return Float64(sin(fma(0.3333333333333333, acos(Float64(Float64(-g) / h)), Float64(pi * 1.1666666666666667))) * 2.0) end
code[g_, h_] := N[(N[Sin[N[(0.3333333333333333 * N[ArcCos[N[((-g) / h), $MachinePrecision]], $MachinePrecision] + N[(Pi * 1.1666666666666667), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * 2.0), $MachinePrecision]
\begin{array}{l}
\\
\sin \left(\mathsf{fma}\left(0.3333333333333333, \cos^{-1} \left(\frac{-g}{h}\right), \pi \cdot 1.1666666666666667\right)\right) \cdot 2
\end{array}
Initial program 98.5%
lift-cos.f64N/A
sin-+PI/2-revN/A
lower-sin.f64N/A
lift-+.f64N/A
+-commutativeN/A
associate-+l+N/A
lift-/.f64N/A
division-flipN/A
associate-/r/N/A
metadata-evalN/A
lower-fma.f64N/A
Applied rewrites97.5%
lift-*.f64N/A
*-commutativeN/A
lower-*.f6497.5
lift-PI.f64N/A
lift-fma.f64N/A
+-commutativeN/A
lift-PI.f64N/A
lift-*.f64N/A
*-commutativeN/A
distribute-rgt-outN/A
lower-*.f64N/A
lift-PI.f64N/A
metadata-eval97.6
Applied rewrites97.6%
herbie shell --seed 2025121
(FPCore (g h)
:name "2-ancestry mixing, negative discriminant"
:precision binary64
(* 2.0 (cos (+ (/ (* 2.0 PI) 3.0) (/ (acos (/ (- g) h)) 3.0)))))