
(FPCore (u1 u2) :precision binary64 (+ (* (* (/ 1.0 6.0) (pow (* -2.0 (log u1)) 0.5)) (cos (* (* 2.0 PI) u2))) 0.5))
double code(double u1, double u2) {
return (((1.0 / 6.0) * pow((-2.0 * log(u1)), 0.5)) * cos(((2.0 * ((double) M_PI)) * u2))) + 0.5;
}
public static double code(double u1, double u2) {
return (((1.0 / 6.0) * Math.pow((-2.0 * Math.log(u1)), 0.5)) * Math.cos(((2.0 * Math.PI) * u2))) + 0.5;
}
def code(u1, u2): return (((1.0 / 6.0) * math.pow((-2.0 * math.log(u1)), 0.5)) * math.cos(((2.0 * math.pi) * u2))) + 0.5
function code(u1, u2) return Float64(Float64(Float64(Float64(1.0 / 6.0) * (Float64(-2.0 * log(u1)) ^ 0.5)) * cos(Float64(Float64(2.0 * pi) * u2))) + 0.5) end
function tmp = code(u1, u2) tmp = (((1.0 / 6.0) * ((-2.0 * log(u1)) ^ 0.5)) * cos(((2.0 * pi) * u2))) + 0.5; end
code[u1_, u2_] := N[(N[(N[(N[(1.0 / 6.0), $MachinePrecision] * N[Power[N[(-2.0 * N[Log[u1], $MachinePrecision]), $MachinePrecision], 0.5], $MachinePrecision]), $MachinePrecision] * N[Cos[N[(N[(2.0 * Pi), $MachinePrecision] * u2), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] + 0.5), $MachinePrecision]
\begin{array}{l}
\\
\left(\frac{1}{6} \cdot {\left(-2 \cdot \log u1\right)}^{0.5}\right) \cdot \cos \left(\left(2 \cdot \pi\right) \cdot u2\right) + 0.5
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 3 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (u1 u2) :precision binary64 (+ (* (* (/ 1.0 6.0) (pow (* -2.0 (log u1)) 0.5)) (cos (* (* 2.0 PI) u2))) 0.5))
double code(double u1, double u2) {
return (((1.0 / 6.0) * pow((-2.0 * log(u1)), 0.5)) * cos(((2.0 * ((double) M_PI)) * u2))) + 0.5;
}
public static double code(double u1, double u2) {
return (((1.0 / 6.0) * Math.pow((-2.0 * Math.log(u1)), 0.5)) * Math.cos(((2.0 * Math.PI) * u2))) + 0.5;
}
def code(u1, u2): return (((1.0 / 6.0) * math.pow((-2.0 * math.log(u1)), 0.5)) * math.cos(((2.0 * math.pi) * u2))) + 0.5
function code(u1, u2) return Float64(Float64(Float64(Float64(1.0 / 6.0) * (Float64(-2.0 * log(u1)) ^ 0.5)) * cos(Float64(Float64(2.0 * pi) * u2))) + 0.5) end
function tmp = code(u1, u2) tmp = (((1.0 / 6.0) * ((-2.0 * log(u1)) ^ 0.5)) * cos(((2.0 * pi) * u2))) + 0.5; end
code[u1_, u2_] := N[(N[(N[(N[(1.0 / 6.0), $MachinePrecision] * N[Power[N[(-2.0 * N[Log[u1], $MachinePrecision]), $MachinePrecision], 0.5], $MachinePrecision]), $MachinePrecision] * N[Cos[N[(N[(2.0 * Pi), $MachinePrecision] * u2), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] + 0.5), $MachinePrecision]
\begin{array}{l}
\\
\left(\frac{1}{6} \cdot {\left(-2 \cdot \log u1\right)}^{0.5}\right) \cdot \cos \left(\left(2 \cdot \pi\right) \cdot u2\right) + 0.5
\end{array}
(FPCore (u1 u2) :precision binary64 (fma (sqrt (* (log u1) -0.05555555555555555)) (cos (* PI (+ u2 u2))) 0.5))
double code(double u1, double u2) {
return fma(sqrt((log(u1) * -0.05555555555555555)), cos((((double) M_PI) * (u2 + u2))), 0.5);
}
function code(u1, u2) return fma(sqrt(Float64(log(u1) * -0.05555555555555555)), cos(Float64(pi * Float64(u2 + u2))), 0.5) end
code[u1_, u2_] := N[(N[Sqrt[N[(N[Log[u1], $MachinePrecision] * -0.05555555555555555), $MachinePrecision]], $MachinePrecision] * N[Cos[N[(Pi * N[(u2 + u2), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + 0.5), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\sqrt{\log u1 \cdot -0.05555555555555555}, \cos \left(\pi \cdot \left(u2 + u2\right)\right), 0.5\right)
\end{array}
Initial program 99.4%
lift-/.f64N/A
lift-log.f64N/A
lift-*.f64N/A
lift-pow.f64N/A
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f64N/A
lift-*.f64N/A
lift-cos.f64N/A
lower-fma.f6499.4
Applied rewrites99.4%
lift-log.f64N/A
lift-*.f64N/A
rem-exp-logN/A
unpow1/2N/A
metadata-evalN/A
unpow1/2N/A
pow-prod-downN/A
rem-exp-logN/A
*-commutativeN/A
lift-*.f64N/A
unpow1/2N/A
lower-sqrt.f6499.6
lift-*.f64N/A
lift-*.f64N/A
associate-*r*N/A
*-commutativeN/A
lower-*.f64N/A
metadata-eval99.6
Applied rewrites99.6%
lift-PI.f64N/A
lift-*.f64N/A
lift-*.f64N/A
lift-cos.f6499.6
lift-*.f64N/A
count-2N/A
lift-*.f64N/A
lift-*.f64N/A
distribute-lft-outN/A
lower-*.f64N/A
lower-+.f6499.6
Applied rewrites99.6%
(FPCore (u1 u2) :precision binary64 (fma (sqrt (* (log u1) -0.05555555555555555)) (fma u2 (* u2 (* -2.0 (* PI PI))) 1.0) 0.5))
double code(double u1, double u2) {
return fma(sqrt((log(u1) * -0.05555555555555555)), fma(u2, (u2 * (-2.0 * (((double) M_PI) * ((double) M_PI)))), 1.0), 0.5);
}
function code(u1, u2) return fma(sqrt(Float64(log(u1) * -0.05555555555555555)), fma(u2, Float64(u2 * Float64(-2.0 * Float64(pi * pi))), 1.0), 0.5) end
code[u1_, u2_] := N[(N[Sqrt[N[(N[Log[u1], $MachinePrecision] * -0.05555555555555555), $MachinePrecision]], $MachinePrecision] * N[(u2 * N[(u2 * N[(-2.0 * N[(Pi * Pi), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + 1.0), $MachinePrecision] + 0.5), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\sqrt{\log u1 \cdot -0.05555555555555555}, \mathsf{fma}\left(u2, u2 \cdot \left(-2 \cdot \left(\pi \cdot \pi\right)\right), 1\right), 0.5\right)
\end{array}
Initial program 99.4%
lift-/.f64N/A
lift-log.f64N/A
lift-*.f64N/A
lift-pow.f64N/A
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f64N/A
lift-*.f64N/A
lift-cos.f64N/A
lower-fma.f6499.4
Applied rewrites99.4%
lift-log.f64N/A
lift-*.f64N/A
rem-exp-logN/A
unpow1/2N/A
metadata-evalN/A
unpow1/2N/A
pow-prod-downN/A
rem-exp-logN/A
*-commutativeN/A
lift-*.f64N/A
unpow1/2N/A
lower-sqrt.f6499.6
lift-*.f64N/A
lift-*.f64N/A
associate-*r*N/A
*-commutativeN/A
lower-*.f64N/A
metadata-eval99.6
Applied rewrites99.6%
lift-approx98.2
Applied rewrites98.2%
(FPCore (u1 u2) :precision binary64 (fma (sqrt (* (log u1) -0.05555555555555555)) 1.0 0.5))
double code(double u1, double u2) {
return fma(sqrt((log(u1) * -0.05555555555555555)), 1.0, 0.5);
}
function code(u1, u2) return fma(sqrt(Float64(log(u1) * -0.05555555555555555)), 1.0, 0.5) end
code[u1_, u2_] := N[(N[Sqrt[N[(N[Log[u1], $MachinePrecision] * -0.05555555555555555), $MachinePrecision]], $MachinePrecision] * 1.0 + 0.5), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\sqrt{\log u1 \cdot -0.05555555555555555}, 1, 0.5\right)
\end{array}
Initial program 99.4%
Taylor expanded in u1 around inf
lower-*.f64N/A
lower-sqrt.f64N/A
log-recN/A
lower-neg.f64N/A
lower-log.f64N/A
lower-sqrt.f6499.5
Applied rewrites99.5%
lift-PI.f6499.5
rem-square-sqrtN/A
sqrt-unprodN/A
lift-PI.f64N/A
add-sqr-sqrtN/A
associate-*r*N/A
sqrt-prodN/A
lower-*.f64N/A
lower-sqrt.f64N/A
lower-*.f64N/A
lift-PI.f64N/A
lower-sqrt.f64N/A
lower-sqrt.f64N/A
lift-PI.f64N/A
lower-sqrt.f6499.5
Applied rewrites99.5%
Applied rewrites97.6%
herbie shell --seed 2024212
(FPCore (u1 u2)
:name "normal distribution"
:precision binary64
:pre (and (and (<= 0.0 u1) (<= u1 1.0)) (and (<= 0.0 u2) (<= u2 1.0)))
(+ (* (* (/ 1.0 6.0) (pow (* -2.0 (log u1)) 0.5)) (cos (* (* 2.0 PI) u2))) 0.5))