
(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]
2 \cdot \cos \left(\frac{2 \cdot \pi}{3} + \frac{\cos^{-1} \left(\frac{-g}{h}\right)}{3}\right)
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]
2 \cdot \cos \left(\frac{2 \cdot \pi}{3} + \frac{\cos^{-1} \left(\frac{-g}{h}\right)}{3}\right)
(FPCore (g h)
:precision binary64
(let* ((t_0 (acos (/ (- g) h))))
(*
(fma
(cos (* 0.3333333333333333 t_0))
-0.5
(* (sin (* t_0 -0.3333333333333333)) 0.8660254037844386))
2.0)))double code(double g, double h) {
double t_0 = acos((-g / h));
return fma(cos((0.3333333333333333 * t_0)), -0.5, (sin((t_0 * -0.3333333333333333)) * 0.8660254037844386)) * 2.0;
}
function code(g, h) t_0 = acos(Float64(Float64(-g) / h)) return Float64(fma(cos(Float64(0.3333333333333333 * t_0)), -0.5, Float64(sin(Float64(t_0 * -0.3333333333333333)) * 0.8660254037844386)) * 2.0) end
code[g_, h_] := Block[{t$95$0 = N[ArcCos[N[((-g) / h), $MachinePrecision]], $MachinePrecision]}, N[(N[(N[Cos[N[(0.3333333333333333 * t$95$0), $MachinePrecision]], $MachinePrecision] * -0.5 + N[(N[Sin[N[(t$95$0 * -0.3333333333333333), $MachinePrecision]], $MachinePrecision] * 0.8660254037844386), $MachinePrecision]), $MachinePrecision] * 2.0), $MachinePrecision]]
\begin{array}{l}
t_0 := \cos^{-1} \left(\frac{-g}{h}\right)\\
\mathsf{fma}\left(\cos \left(0.3333333333333333 \cdot t\_0\right), -0.5, \sin \left(t\_0 \cdot -0.3333333333333333\right) \cdot 0.8660254037844386\right) \cdot 2
\end{array}
Initial program 98.5%
Applied rewrites98.4%
Applied rewrites100.0%
Evaluated real constant100.0%
lift--.f64N/A
lift-*.f64N/A
fp-cancel-sub-sign-invN/A
lift-*.f64N/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites100.0%
(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(Float64(-g) / 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]
2 \cdot \cos \left(\mathsf{fma}\left(\pi, 0.6666666666666666, 0.3333333333333333 \cdot \cos^{-1} \left(\frac{-g}{h}\right)\right)\right)
Initial program 98.5%
lift-+.f64N/A
lift-/.f64N/A
add-to-fractionN/A
div-addN/A
lift-/.f64N/A
mult-flipN/A
associate-*l*N/A
metadata-evalN/A
metadata-evalN/A
associate-*r/N/A
mult-flipN/A
lift-*.f64N/A
*-commutativeN/A
associate-/l*N/A
lift-/.f64N/A
lower-fma.f64N/A
metadata-eval98.5
lift-/.f64N/A
mult-flipN/A
Applied rewrites98.5%
(FPCore (g h) :precision binary64 (* (cos (fma -0.3333333333333333 (acos (/ (- g) h)) -2.0943951023931957)) 2.0))
double code(double g, double h) {
return cos(fma(-0.3333333333333333, acos((-g / h)), -2.0943951023931957)) * 2.0;
}
function code(g, h) return Float64(cos(fma(-0.3333333333333333, acos(Float64(Float64(-g) / h)), -2.0943951023931957)) * 2.0) end
code[g_, h_] := N[(N[Cos[N[(-0.3333333333333333 * N[ArcCos[N[((-g) / h), $MachinePrecision]], $MachinePrecision] + -2.0943951023931957), $MachinePrecision]], $MachinePrecision] * 2.0), $MachinePrecision]
\cos \left(\mathsf{fma}\left(-0.3333333333333333, \cos^{-1} \left(\frac{-g}{h}\right), -2.0943951023931957\right)\right) \cdot 2
Initial program 98.5%
Evaluated real constant98.4%
lift-*.f64N/A
*-commutativeN/A
lower-*.f6498.4
Applied rewrites98.4%
(FPCore (g h) :precision binary64 (* (sin (fma 0.3333333333333333 (acos (/ (- g) h)) 3.6651914291880923)) 2.0))
double code(double g, double h) {
return sin(fma(0.3333333333333333, acos((-g / h)), 3.6651914291880923)) * 2.0;
}
function code(g, h) return Float64(sin(fma(0.3333333333333333, acos(Float64(Float64(-g) / h)), 3.6651914291880923)) * 2.0) end
code[g_, h_] := N[(N[Sin[N[(0.3333333333333333 * N[ArcCos[N[((-g) / h), $MachinePrecision]], $MachinePrecision] + 3.6651914291880923), $MachinePrecision]], $MachinePrecision] * 2.0), $MachinePrecision]
\sin \left(\mathsf{fma}\left(0.3333333333333333, \cos^{-1} \left(\frac{-g}{h}\right), 3.6651914291880923\right)\right) \cdot 2
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
mult-flipN/A
*-commutativeN/A
lower-fma.f64N/A
metadata-evalN/A
lift-/.f64N/A
lift-*.f64N/A
*-commutativeN/A
associate-/l*N/A
Applied rewrites97.5%
Evaluated real constant97.6%
lift-*.f64N/A
*-commutativeN/A
lower-*.f6497.6
Applied rewrites97.6%
herbie shell --seed 2025174
(FPCore (g h)
:name "2-ancestry mixing, negative discriminant"
:precision binary64
(* 2.0 (cos (+ (/ (* 2.0 PI) 3.0) (/ (acos (/ (- g) h)) 3.0)))))