
(FPCore (v) :precision binary64 (acos (/ (- 1.0 (* 5.0 (* v v))) (- (* v v) 1.0))))
double code(double v) {
return acos(((1.0 - (5.0 * (v * v))) / ((v * v) - 1.0)));
}
real(8) function code(v)
real(8), intent (in) :: v
code = acos(((1.0d0 - (5.0d0 * (v * v))) / ((v * v) - 1.0d0)))
end function
public static double code(double v) {
return Math.acos(((1.0 - (5.0 * (v * v))) / ((v * v) - 1.0)));
}
def code(v): return math.acos(((1.0 - (5.0 * (v * v))) / ((v * v) - 1.0)))
function code(v) return acos(Float64(Float64(1.0 - Float64(5.0 * Float64(v * v))) / Float64(Float64(v * v) - 1.0))) end
function tmp = code(v) tmp = acos(((1.0 - (5.0 * (v * v))) / ((v * v) - 1.0))); end
code[v_] := N[ArcCos[N[(N[(1.0 - N[(5.0 * N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(N[(v * v), $MachinePrecision] - 1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}
\\
\cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right)
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 5 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (v) :precision binary64 (acos (/ (- 1.0 (* 5.0 (* v v))) (- (* v v) 1.0))))
double code(double v) {
return acos(((1.0 - (5.0 * (v * v))) / ((v * v) - 1.0)));
}
real(8) function code(v)
real(8), intent (in) :: v
code = acos(((1.0d0 - (5.0d0 * (v * v))) / ((v * v) - 1.0d0)))
end function
public static double code(double v) {
return Math.acos(((1.0 - (5.0 * (v * v))) / ((v * v) - 1.0)));
}
def code(v): return math.acos(((1.0 - (5.0 * (v * v))) / ((v * v) - 1.0)))
function code(v) return acos(Float64(Float64(1.0 - Float64(5.0 * Float64(v * v))) / Float64(Float64(v * v) - 1.0))) end
function tmp = code(v) tmp = acos(((1.0 - (5.0 * (v * v))) / ((v * v) - 1.0))); end
code[v_] := N[ArcCos[N[(N[(1.0 - N[(5.0 * N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(N[(v * v), $MachinePrecision] - 1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}
\\
\cos^{-1} \left(\frac{1 - 5 \cdot \left(v \cdot v\right)}{v \cdot v - 1}\right)
\end{array}
(FPCore (v)
:precision binary64
(let* ((t_0 (/ (fma v (* v -5.0) 1.0) (fma v v -1.0))) (t_1 (asin t_0)))
(*
(- (* (* PI (* PI PI)) 0.125) (pow (fma PI 0.5 (- (acos t_0))) 3.0))
(/ 1.0 (fma t_1 (fma PI 0.5 t_1) (* (* PI PI) 0.25))))))
double code(double v) {
double t_0 = fma(v, (v * -5.0), 1.0) / fma(v, v, -1.0);
double t_1 = asin(t_0);
return (((((double) M_PI) * (((double) M_PI) * ((double) M_PI))) * 0.125) - pow(fma(((double) M_PI), 0.5, -acos(t_0)), 3.0)) * (1.0 / fma(t_1, fma(((double) M_PI), 0.5, t_1), ((((double) M_PI) * ((double) M_PI)) * 0.25)));
}
function code(v) t_0 = Float64(fma(v, Float64(v * -5.0), 1.0) / fma(v, v, -1.0)) t_1 = asin(t_0) return Float64(Float64(Float64(Float64(pi * Float64(pi * pi)) * 0.125) - (fma(pi, 0.5, Float64(-acos(t_0))) ^ 3.0)) * Float64(1.0 / fma(t_1, fma(pi, 0.5, t_1), Float64(Float64(pi * pi) * 0.25)))) end
code[v_] := Block[{t$95$0 = N[(N[(v * N[(v * -5.0), $MachinePrecision] + 1.0), $MachinePrecision] / N[(v * v + -1.0), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[ArcSin[t$95$0], $MachinePrecision]}, N[(N[(N[(N[(Pi * N[(Pi * Pi), $MachinePrecision]), $MachinePrecision] * 0.125), $MachinePrecision] - N[Power[N[(Pi * 0.5 + (-N[ArcCos[t$95$0], $MachinePrecision])), $MachinePrecision], 3.0], $MachinePrecision]), $MachinePrecision] * N[(1.0 / N[(t$95$1 * N[(Pi * 0.5 + t$95$1), $MachinePrecision] + N[(N[(Pi * Pi), $MachinePrecision] * 0.25), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{\mathsf{fma}\left(v, v \cdot -5, 1\right)}{\mathsf{fma}\left(v, v, -1\right)}\\
t_1 := \sin^{-1} t\_0\\
\left(\left(\pi \cdot \left(\pi \cdot \pi\right)\right) \cdot 0.125 - {\left(\mathsf{fma}\left(\pi, 0.5, -\cos^{-1} t\_0\right)\right)}^{3}\right) \cdot \frac{1}{\mathsf{fma}\left(t\_1, \mathsf{fma}\left(\pi, 0.5, t\_1\right), \left(\pi \cdot \pi\right) \cdot 0.25\right)}
\end{array}
\end{array}
Initial program 98.8%
Applied egg-rr98.8%
lift-*.f64N/A
lift-fma.f64N/A
lift-fma.f64N/A
lift-/.f64N/A
asin-acosN/A
lift-acos.f64N/A
sub-negN/A
lift-PI.f64N/A
div-invN/A
metadata-evalN/A
lift-acos.f64N/A
acos-asinN/A
lift-PI.f64N/A
div-invN/A
metadata-evalN/A
lift-asin.f64N/A
Applied egg-rr98.9%
(FPCore (v) :precision binary64 (acos (/ (fma v (* v -5.0) 1.0) (fma v v -1.0))))
double code(double v) {
return acos((fma(v, (v * -5.0), 1.0) / fma(v, v, -1.0)));
}
function code(v) return acos(Float64(fma(v, Float64(v * -5.0), 1.0) / fma(v, v, -1.0))) end
code[v_] := N[ArcCos[N[(N[(v * N[(v * -5.0), $MachinePrecision] + 1.0), $MachinePrecision] / N[(v * v + -1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}
\\
\cos^{-1} \left(\frac{\mathsf{fma}\left(v, v \cdot -5, 1\right)}{\mathsf{fma}\left(v, v, -1\right)}\right)
\end{array}
Initial program 98.8%
lift-*.f64N/A
lift-*.f64N/A
lift-*.f64N/A
lift--.f64N/A
lift--.f64N/A
lift-/.f64N/A
lift-acos.f6498.8
Applied egg-rr98.8%
(FPCore (v) :precision binary64 (acos (fma v (* v (fma (* v v) 4.0 4.0)) -1.0)))
double code(double v) {
return acos(fma(v, (v * fma((v * v), 4.0, 4.0)), -1.0));
}
function code(v) return acos(fma(v, Float64(v * fma(Float64(v * v), 4.0, 4.0)), -1.0)) end
code[v_] := N[ArcCos[N[(v * N[(v * N[(N[(v * v), $MachinePrecision] * 4.0 + 4.0), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}
\\
\cos^{-1} \left(\mathsf{fma}\left(v, v \cdot \mathsf{fma}\left(v \cdot v, 4, 4\right), -1\right)\right)
\end{array}
Initial program 98.8%
Taylor expanded in v around 0
sub-negN/A
unpow2N/A
associate-*l*N/A
*-commutativeN/A
metadata-evalN/A
lower-fma.f64N/A
*-commutativeN/A
lower-*.f64N/A
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
unpow2N/A
lower-*.f6498.1
Simplified98.1%
(FPCore (v) :precision binary64 (acos (fma v (* v 4.0) -1.0)))
double code(double v) {
return acos(fma(v, (v * 4.0), -1.0));
}
function code(v) return acos(fma(v, Float64(v * 4.0), -1.0)) end
code[v_] := N[ArcCos[N[(v * N[(v * 4.0), $MachinePrecision] + -1.0), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}
\\
\cos^{-1} \left(\mathsf{fma}\left(v, v \cdot 4, -1\right)\right)
\end{array}
Initial program 98.8%
Taylor expanded in v around 0
sub-negN/A
unpow2N/A
associate-*r*N/A
*-commutativeN/A
metadata-evalN/A
lower-fma.f64N/A
*-commutativeN/A
lower-*.f6497.9
Simplified97.9%
(FPCore (v) :precision binary64 (acos -1.0))
double code(double v) {
return acos(-1.0);
}
real(8) function code(v)
real(8), intent (in) :: v
code = acos((-1.0d0))
end function
public static double code(double v) {
return Math.acos(-1.0);
}
def code(v): return math.acos(-1.0)
function code(v) return acos(-1.0) end
function tmp = code(v) tmp = acos(-1.0); end
code[v_] := N[ArcCos[-1.0], $MachinePrecision]
\begin{array}{l}
\\
\cos^{-1} -1
\end{array}
Initial program 98.8%
Taylor expanded in v around 0
Simplified97.1%
herbie shell --seed 2024210
(FPCore (v)
:name "Falkner and Boettcher, Appendix B, 1"
:precision binary64
(acos (/ (- 1.0 (* 5.0 (* v v))) (- (* v v) 1.0))))