
(FPCore (u1 u2) :precision binary64 (+ (* (* (/ 1.0 6.0) (pow (* -2.0 (log u1)) 0.5)) (cos (* (* 2.0 (PI)) u2))) 0.5))
\begin{array}{l}
\\
\left(\frac{1}{6} \cdot {\left(-2 \cdot \log u1\right)}^{0.5}\right) \cdot \cos \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right) + 0.5
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 7 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))
\begin{array}{l}
\\
\left(\frac{1}{6} \cdot {\left(-2 \cdot \log u1\right)}^{0.5}\right) \cdot \cos \left(\left(2 \cdot \mathsf{PI}\left(\right)\right) \cdot u2\right) + 0.5
\end{array}
(FPCore (u1 u2) :precision binary64 (fma (* (* (sqrt 2.0) 0.16666666666666666) (cos (* (* (PI) u2) -2.0))) (sqrt (- (log u1))) 0.5))
\begin{array}{l}
\\
\mathsf{fma}\left(\left(\sqrt{2} \cdot 0.16666666666666666\right) \cdot \cos \left(\left(\mathsf{PI}\left(\right) \cdot u2\right) \cdot -2\right), \sqrt{-\log u1}, 0.5\right)
\end{array}
Initial program 99.4%
lift-pow.f64N/A
pow-to-expN/A
*-commutativeN/A
exp-prodN/A
lower-pow.f64N/A
lower-exp.f64N/A
lower-log.f6498.9
lift-*.f64N/A
*-commutativeN/A
lower-*.f6498.9
Applied rewrites98.9%
Taylor expanded in u1 around inf
+-commutativeN/A
associate-*r*N/A
lower-fma.f64N/A
Applied rewrites99.6%
(FPCore (u1 u2) :precision binary64 (fma (sqrt 2.0) (* 0.16666666666666666 (* (cos (* (* (PI) 2.0) u2)) (sqrt (- (log u1))))) 0.5))
\begin{array}{l}
\\
\mathsf{fma}\left(\sqrt{2}, 0.16666666666666666 \cdot \left(\cos \left(\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot u2\right) \cdot \sqrt{-\log u1}\right), 0.5\right)
\end{array}
Initial program 99.4%
lift-pow.f64N/A
pow-to-expN/A
*-commutativeN/A
exp-prodN/A
lower-pow.f64N/A
lower-exp.f64N/A
lower-log.f6498.9
lift-*.f64N/A
*-commutativeN/A
lower-*.f6498.9
Applied rewrites98.9%
Taylor expanded in u1 around inf
+-commutativeN/A
associate-*r*N/A
lower-fma.f64N/A
Applied rewrites99.6%
Applied rewrites99.4%
(FPCore (u1 u2) :precision binary64 (fma (* (cos (* u2 (* (PI) 2.0))) 0.16666666666666666) (sqrt (* (log u1) -2.0)) 0.5))
\begin{array}{l}
\\
\mathsf{fma}\left(\cos \left(u2 \cdot \left(\mathsf{PI}\left(\right) \cdot 2\right)\right) \cdot 0.16666666666666666, \sqrt{\log u1 \cdot -2}, 0.5\right)
\end{array}
Initial program 99.4%
lift-pow.f64N/A
unpow1/2N/A
lower-sqrt.f6499.4
lift-*.f64N/A
*-commutativeN/A
lower-*.f6499.4
Applied rewrites99.4%
lift-+.f64N/A
lift-*.f64N/A
*-commutativeN/A
lift-*.f64N/A
associate-*r*N/A
lower-fma.f64N/A
lower-*.f6499.4
lift-*.f64N/A
*-commutativeN/A
lower-*.f6499.4
lift-*.f64N/A
*-commutativeN/A
lower-*.f6499.4
lift-/.f64N/A
metadata-eval99.4
Applied rewrites99.4%
(FPCore (u1 u2) :precision binary64 (fma (* (sqrt 2.0) (fma (* u2 u2) (* (* (PI) (PI)) -0.3333333333333333) 0.16666666666666666)) (sqrt (- (log u1))) 0.5))
\begin{array}{l}
\\
\mathsf{fma}\left(\sqrt{2} \cdot \mathsf{fma}\left(u2 \cdot u2, \left(\mathsf{PI}\left(\right) \cdot \mathsf{PI}\left(\right)\right) \cdot -0.3333333333333333, 0.16666666666666666\right), \sqrt{-\log u1}, 0.5\right)
\end{array}
Initial program 99.4%
lift-pow.f64N/A
pow-to-expN/A
*-commutativeN/A
exp-prodN/A
lower-pow.f64N/A
lower-exp.f64N/A
lower-log.f6498.9
lift-*.f64N/A
*-commutativeN/A
lower-*.f6498.9
Applied rewrites98.9%
Taylor expanded in u1 around inf
+-commutativeN/A
associate-*r*N/A
lower-fma.f64N/A
Applied rewrites99.6%
Taylor expanded in u2 around 0
Applied rewrites98.3%
(FPCore (u1 u2) :precision binary64 (fma (* (fma (* (* -2.0 u2) u2) (* (PI) (PI)) 1.0) 0.16666666666666666) (sqrt (* (log u1) -2.0)) 0.5))
\begin{array}{l}
\\
\mathsf{fma}\left(\mathsf{fma}\left(\left(-2 \cdot u2\right) \cdot u2, \mathsf{PI}\left(\right) \cdot \mathsf{PI}\left(\right), 1\right) \cdot 0.16666666666666666, \sqrt{\log u1 \cdot -2}, 0.5\right)
\end{array}
Initial program 99.4%
lift-pow.f64N/A
unpow1/2N/A
lower-sqrt.f6499.4
lift-*.f64N/A
*-commutativeN/A
lower-*.f6499.4
Applied rewrites99.4%
lift-+.f64N/A
lift-*.f64N/A
*-commutativeN/A
lift-*.f64N/A
associate-*r*N/A
lower-fma.f64N/A
lower-*.f6499.4
lift-*.f64N/A
*-commutativeN/A
lower-*.f6499.4
lift-*.f64N/A
*-commutativeN/A
lower-*.f6499.4
lift-/.f64N/A
metadata-eval99.4
Applied rewrites99.4%
Taylor expanded in u2 around 0
+-commutativeN/A
associate-*r*N/A
lower-fma.f64N/A
unpow2N/A
associate-*r*N/A
lower-*.f64N/A
lower-*.f64N/A
unpow2N/A
lower-*.f64N/A
lower-PI.f64N/A
lower-PI.f6498.1
Applied rewrites98.1%
(FPCore (u1 u2) :precision binary64 (fma (fma (* (* u2 u2) -0.3333333333333333) (* (PI) (PI)) 0.16666666666666666) (sqrt (* (log u1) -2.0)) 0.5))
\begin{array}{l}
\\
\mathsf{fma}\left(\mathsf{fma}\left(\left(u2 \cdot u2\right) \cdot -0.3333333333333333, \mathsf{PI}\left(\right) \cdot \mathsf{PI}\left(\right), 0.16666666666666666\right), \sqrt{\log u1 \cdot -2}, 0.5\right)
\end{array}
Initial program 99.4%
lift-pow.f64N/A
unpow1/2N/A
lower-sqrt.f6499.4
lift-*.f64N/A
*-commutativeN/A
lower-*.f6499.4
Applied rewrites99.4%
lift-+.f64N/A
lift-*.f64N/A
*-commutativeN/A
lift-*.f64N/A
associate-*r*N/A
lower-fma.f64N/A
lower-*.f6499.4
lift-*.f64N/A
*-commutativeN/A
lower-*.f6499.4
lift-*.f64N/A
*-commutativeN/A
lower-*.f6499.4
lift-/.f64N/A
metadata-eval99.4
Applied rewrites99.4%
Taylor expanded in u2 around 0
+-commutativeN/A
associate-*r*N/A
lower-fma.f64N/A
*-commutativeN/A
lower-*.f64N/A
unpow2N/A
lower-*.f64N/A
unpow2N/A
lower-*.f64N/A
lower-PI.f64N/A
lower-PI.f6498.1
Applied rewrites98.1%
(FPCore (u1 u2) :precision binary64 (+ (sqrt (* (log u1) -0.05555555555555555)) 0.5))
double code(double u1, double u2) {
return sqrt((log(u1) * -0.05555555555555555)) + 0.5;
}
real(8) function code(u1, u2)
real(8), intent (in) :: u1
real(8), intent (in) :: u2
code = sqrt((log(u1) * (-0.05555555555555555d0))) + 0.5d0
end function
public static double code(double u1, double u2) {
return Math.sqrt((Math.log(u1) * -0.05555555555555555)) + 0.5;
}
def code(u1, u2): return math.sqrt((math.log(u1) * -0.05555555555555555)) + 0.5
function code(u1, u2) return Float64(sqrt(Float64(log(u1) * -0.05555555555555555)) + 0.5) end
function tmp = code(u1, u2) tmp = sqrt((log(u1) * -0.05555555555555555)) + 0.5; end
code[u1_, u2_] := N[(N[Sqrt[N[(N[Log[u1], $MachinePrecision] * -0.05555555555555555), $MachinePrecision]], $MachinePrecision] + 0.5), $MachinePrecision]
\begin{array}{l}
\\
\sqrt{\log u1 \cdot -0.05555555555555555} + 0.5
\end{array}
Initial program 99.4%
Applied rewrites98.1%
lift-*.f64N/A
lift-pow.f64N/A
unpow1N/A
lift-*.f64N/A
associate-*l*N/A
metadata-evalN/A
metadata-evalN/A
lower-*.f64N/A
metadata-eval98.1
Applied rewrites98.1%
herbie shell --seed 2024337
(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))