
(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 (* 2.0 (sin (fma PI -0.16666666666666666 (* -0.3333333333333333 (acos (/ (- g) h)))))))
double code(double g, double h) {
return 2.0 * sin(fma(((double) M_PI), -0.16666666666666666, (-0.3333333333333333 * acos((-g / h)))));
}
function code(g, h) return Float64(2.0 * sin(fma(pi, -0.16666666666666666, Float64(-0.3333333333333333 * acos(Float64(Float64(-g) / h)))))) end
code[g_, h_] := N[(2.0 * N[Sin[N[(Pi * -0.16666666666666666 + N[(-0.3333333333333333 * N[ArcCos[N[((-g) / h), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
2 \cdot \sin \left(\mathsf{fma}\left(\pi, -0.16666666666666666, -0.3333333333333333 \cdot \cos^{-1} \left(\frac{-g}{h}\right)\right)\right)
\end{array}
Initial program 98.5%
lift-cos.f64N/A
cos-neg-revN/A
sin-+PI/2-revN/A
lower-sin.f64N/A
lower-+.f64N/A
Applied rewrites98.5%
Taylor expanded in g around 0
Applied rewrites99.9%
lift-fma.f64N/A
+-commutativeN/A
lift-PI.f64N/A
lift-fma.f64N/A
lift-PI.f64N/A
lift-*.f64N/A
*-commutativeN/A
distribute-lft-outN/A
metadata-evalN/A
lift-acos.f64N/A
lift-neg.f64N/A
lift-/.f64N/A
acos-asinN/A
distribute-frac-negN/A
mul-1-negN/A
acos-asinN/A
lower-fma.f64N/A
lift-PI.f64N/A
Applied rewrites100.0%
(FPCore (g h) :precision binary64 (* 2.0 (cos (* (fma PI 2.0 (acos (/ (- g) h))) 0.3333333333333333))))
double code(double g, double h) {
return 2.0 * cos((fma(((double) M_PI), 2.0, acos((-g / h))) * 0.3333333333333333));
}
function code(g, h) return Float64(2.0 * cos(Float64(fma(pi, 2.0, acos(Float64(Float64(-g) / h))) * 0.3333333333333333))) end
code[g_, h_] := N[(2.0 * N[Cos[N[(N[(Pi * 2.0 + N[ArcCos[N[((-g) / h), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * 0.3333333333333333), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
2 \cdot \cos \left(\mathsf{fma}\left(\pi, 2, \cos^{-1} \left(\frac{-g}{h}\right)\right) \cdot 0.3333333333333333\right)
\end{array}
Initial program 98.5%
Taylor expanded in g around 0
mul-1-negN/A
distribute-frac-negN/A
lower-fma.f64N/A
lift-/.f64N/A
lift-neg.f64N/A
lift-acos.f64N/A
lower-*.f64N/A
lift-PI.f6498.4
Applied rewrites98.4%
lift-fma.f64N/A
+-commutativeN/A
lift-PI.f64N/A
lift-*.f64N/A
metadata-evalN/A
associate-*r*N/A
distribute-lft-inN/A
*-commutativeN/A
lift-fma.f64N/A
lift-PI.f64N/A
*-commutativeN/A
lower-*.f6498.5
Applied rewrites98.5%
herbie shell --seed 2025107
(FPCore (g h)
:name "2-ancestry mixing, negative discriminant"
:precision binary64
(* 2.0 (cos (+ (/ (* 2.0 PI) 3.0) (/ (acos (/ (- g) h)) 3.0)))))