
(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 6 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 (- (log u1))) (cos (* 2.0 (* (PI) u2)))) (* 0.16666666666666666 (sqrt 2.0)) 0.5))
\begin{array}{l}
\\
\mathsf{fma}\left(\sqrt{-\log u1} \cdot \cos \left(2 \cdot \left(\mathsf{PI}\left(\right) \cdot u2\right)\right), 0.16666666666666666 \cdot \sqrt{2}, 0.5\right)
\end{array}
Initial program 99.3%
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.f6499.4
Applied rewrites99.4%
lift-/.f64N/A
lift-log.f64N/A
lift-neg.f64N/A
lift-sqrt.f64N/A
lift-sqrt.f64N/A
*-commutativeN/A
associate-*r*N/A
lift-sqrt.f64N/A
pow1/2N/A
metadata-evalN/A
pow-prod-upN/A
pow-prod-downN/A
metadata-evalN/A
metadata-evalN/A
pow-prod-downN/A
pow-prod-upN/A
metadata-evalN/A
pow1/2N/A
lift-sqrt.f64N/A
*-commutativeN/A
lift-/.f64N/A
metadata-evalN/A
lift-*.f64N/A
lower-*.f640.0
Applied rewrites99.5%
lift-sqrt.f64N/A
lift-*.f64N/A
lift-log.f64N/A
lift-neg.f64N/A
lift-sqrt.f64N/A
lift-PI.f64N/A
lift-*.f64N/A
lift-*.f64N/A
lift-cos.f64N/A
associate-*l*N/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites99.6%
(FPCore (u1 u2) :precision binary64 (fma (* (cos (* 2.0 (* (PI) u2))) (* (sqrt (- (log u1))) 0.16666666666666666)) (sqrt 2.0) 0.5))
\begin{array}{l}
\\
\mathsf{fma}\left(\cos \left(2 \cdot \left(\mathsf{PI}\left(\right) \cdot u2\right)\right) \cdot \left(\sqrt{-\log u1} \cdot 0.16666666666666666\right), \sqrt{2}, 0.5\right)
\end{array}
Initial program 99.3%
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.f6499.4
Applied rewrites99.4%
Applied rewrites99.5%
Final simplification99.5%
(FPCore (u1 u2) :precision binary64 (fma (* 0.16666666666666666 (sqrt (* (log u1) -2.0))) (cos (* 2.0 (* (PI) u2))) 0.5))
\begin{array}{l}
\\
\mathsf{fma}\left(0.16666666666666666 \cdot \sqrt{\log u1 \cdot -2}, \cos \left(2 \cdot \left(\mathsf{PI}\left(\right) \cdot u2\right)\right), 0.5\right)
\end{array}
Initial program 99.3%
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.f6499.3
Applied rewrites99.3%
Final simplification99.3%
(FPCore (u1 u2) :precision binary64 (+ 0.5 (* (* (/ 1.0 6.0) (* (sqrt (- (log u1))) (sqrt 2.0))) (fma (* -2.0 (* u2 u2)) (* (PI) (PI)) 1.0))))
\begin{array}{l}
\\
0.5 + \left(\frac{1}{6} \cdot \left(\sqrt{-\log u1} \cdot \sqrt{2}\right)\right) \cdot \mathsf{fma}\left(-2 \cdot \left(u2 \cdot u2\right), \mathsf{PI}\left(\right) \cdot \mathsf{PI}\left(\right), 1\right)
\end{array}
Initial program 99.3%
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.f6499.4
Applied rewrites99.4%
Taylor expanded in u2 around 0
+-commutativeN/A
associate-*r*N/A
lower-fma.f64N/A
rem-square-sqrtN/A
unpow2N/A
lower-*.f64N/A
unpow2N/A
rem-square-sqrtN/A
unpow2N/A
lower-*.f64N/A
unpow2N/A
lower-*.f64N/A
lower-PI.f64N/A
lower-PI.f6498.7
Applied rewrites98.7%
Final simplification98.7%
(FPCore (u1 u2) :precision binary64 (+ 0.5 (* (/ 1.0 6.0) (* (sqrt (- (log u1))) (sqrt 2.0)))))
double code(double u1, double u2) {
return 0.5 + ((1.0 / 6.0) * (sqrt(-log(u1)) * sqrt(2.0)));
}
real(8) function code(u1, u2)
real(8), intent (in) :: u1
real(8), intent (in) :: u2
code = 0.5d0 + ((1.0d0 / 6.0d0) * (sqrt(-log(u1)) * sqrt(2.0d0)))
end function
public static double code(double u1, double u2) {
return 0.5 + ((1.0 / 6.0) * (Math.sqrt(-Math.log(u1)) * Math.sqrt(2.0)));
}
def code(u1, u2): return 0.5 + ((1.0 / 6.0) * (math.sqrt(-math.log(u1)) * math.sqrt(2.0)))
function code(u1, u2) return Float64(0.5 + Float64(Float64(1.0 / 6.0) * Float64(sqrt(Float64(-log(u1))) * sqrt(2.0)))) end
function tmp = code(u1, u2) tmp = 0.5 + ((1.0 / 6.0) * (sqrt(-log(u1)) * sqrt(2.0))); end
code[u1_, u2_] := N[(0.5 + N[(N[(1.0 / 6.0), $MachinePrecision] * N[(N[Sqrt[(-N[Log[u1], $MachinePrecision])], $MachinePrecision] * N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
0.5 + \frac{1}{6} \cdot \left(\sqrt{-\log u1} \cdot \sqrt{2}\right)
\end{array}
Initial program 99.3%
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.f6499.4
Applied rewrites99.4%
Taylor expanded in u2 around 0
Applied rewrites97.6%
Final simplification97.6%
(FPCore (u1 u2) :precision binary64 (fma (sqrt (* (log u1) -2.0)) 0.16666666666666666 0.5))
double code(double u1, double u2) {
return fma(sqrt((log(u1) * -2.0)), 0.16666666666666666, 0.5);
}
function code(u1, u2) return fma(sqrt(Float64(log(u1) * -2.0)), 0.16666666666666666, 0.5) end
code[u1_, u2_] := N[(N[Sqrt[N[(N[Log[u1], $MachinePrecision] * -2.0), $MachinePrecision]], $MachinePrecision] * 0.16666666666666666 + 0.5), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\sqrt{\log u1 \cdot -2}, 0.16666666666666666, 0.5\right)
\end{array}
Initial program 99.3%
Taylor expanded in u2 around 0
+-commutativeN/A
*-commutativeN/A
associate-*l*N/A
*-commutativeN/A
lower-fma.f64N/A
lower-sqrt.f64N/A
lower-log.f64N/A
*-commutativeN/A
lower-*.f64N/A
lower-sqrt.f640.0
Applied rewrites0.0%
lift-log.f64N/A
lift-sqrt.f64N/A
lift-sqrt.f64N/A
lift-*.f64N/A
*-commutativeN/A
lift-*.f64N/A
metadata-evalN/A
lift-/.f64N/A
*-commutativeN/A
associate-*r*N/A
lift-sqrt.f64N/A
lift-sqrt.f64N/A
sqrt-prodN/A
lift-*.f64N/A
lift-sqrt.f64N/A
*-commutativeN/A
lower-fma.f6497.6
Applied rewrites97.6%
herbie shell --seed 2024216
(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))