
(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 (+ (* (cos (* (* (PI) 2.0) u2)) (* (* (sqrt (- (log u1))) (sqrt 2.0)) (/ 1.0 6.0))) 0.5))
\begin{array}{l}
\\
\cos \left(\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot u2\right) \cdot \left(\left(\sqrt{-\log u1} \cdot \sqrt{2}\right) \cdot \frac{1}{6}\right) + 0.5
\end{array}
Initial program 99.4%
Taylor expanded in u1 around inf
*-commutativeN/A
lower-*.f64N/A
lower-sqrt.f64N/A
lower-sqrt.f64N/A
log-recN/A
lower-neg.f64N/A
lower-log.f6499.5
Applied rewrites99.5%
Final simplification99.5%
(FPCore (u1 u2) :precision binary64 (fma (* (sqrt (* (log u1) -2.0)) (cos (* (* (PI) 2.0) u2))) 0.16666666666666666 0.5))
\begin{array}{l}
\\
\mathsf{fma}\left(\sqrt{\log u1 \cdot -2} \cdot \cos \left(\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot u2\right), 0.16666666666666666, 0.5\right)
\end{array}
Initial program 99.4%
lift-+.f64N/A
lift-*.f64N/A
lift-*.f64N/A
associate-*l*N/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites99.4%
Final simplification99.4%
(FPCore (u1 u2) :precision binary64 (+ (* (fma (* (* (PI) (PI)) -2.0) (* u2 u2) 1.0) (* (* (sqrt (- (log u1))) (sqrt 2.0)) (/ 1.0 6.0))) 0.5))
\begin{array}{l}
\\
\mathsf{fma}\left(\left(\mathsf{PI}\left(\right) \cdot \mathsf{PI}\left(\right)\right) \cdot -2, u2 \cdot u2, 1\right) \cdot \left(\left(\sqrt{-\log u1} \cdot \sqrt{2}\right) \cdot \frac{1}{6}\right) + 0.5
\end{array}
Initial program 99.4%
Taylor expanded in u1 around inf
*-commutativeN/A
lower-*.f64N/A
lower-sqrt.f64N/A
lower-sqrt.f64N/A
log-recN/A
lower-neg.f64N/A
lower-log.f6499.5
Applied rewrites99.5%
Taylor expanded in u2 around 0
+-commutativeN/A
rem-square-sqrtN/A
unpow2N/A
*-commutativeN/A
associate-*r*N/A
*-commutativeN/A
unpow2N/A
rem-square-sqrtN/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites99.2%
Final simplification99.2%
(FPCore (u1 u2) :precision binary64 (fma (* (sqrt (* (log u1) -2.0)) (fma (* u2 u2) (* (* (PI) (PI)) -2.0) 1.0)) 0.16666666666666666 0.5))
\begin{array}{l}
\\
\mathsf{fma}\left(\sqrt{\log u1 \cdot -2} \cdot \mathsf{fma}\left(u2 \cdot u2, \left(\mathsf{PI}\left(\right) \cdot \mathsf{PI}\left(\right)\right) \cdot -2, 1\right), 0.16666666666666666, 0.5\right)
\end{array}
Initial program 99.4%
Taylor expanded in u1 around inf
*-commutativeN/A
lower-*.f64N/A
lower-sqrt.f64N/A
lower-sqrt.f64N/A
log-recN/A
lower-neg.f64N/A
lower-log.f6499.5
Applied rewrites99.5%
Taylor expanded in u2 around 0
+-commutativeN/A
rem-square-sqrtN/A
unpow2N/A
*-commutativeN/A
associate-*r*N/A
*-commutativeN/A
unpow2N/A
rem-square-sqrtN/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites99.2%
lift-+.f64N/A
Applied rewrites99.1%
Final simplification99.1%
(FPCore (u1 u2) :precision binary64 (+ (* 1.0 (* 0.16666666666666666 (* (sqrt (- (log u1))) (sqrt 2.0)))) 0.5))
double code(double u1, double u2) {
return (1.0 * (0.16666666666666666 * (sqrt(-log(u1)) * sqrt(2.0)))) + 0.5;
}
real(8) function code(u1, u2)
real(8), intent (in) :: u1
real(8), intent (in) :: u2
code = (1.0d0 * (0.16666666666666666d0 * (sqrt(-log(u1)) * sqrt(2.0d0)))) + 0.5d0
end function
public static double code(double u1, double u2) {
return (1.0 * (0.16666666666666666 * (Math.sqrt(-Math.log(u1)) * Math.sqrt(2.0)))) + 0.5;
}
def code(u1, u2): return (1.0 * (0.16666666666666666 * (math.sqrt(-math.log(u1)) * math.sqrt(2.0)))) + 0.5
function code(u1, u2) return Float64(Float64(1.0 * Float64(0.16666666666666666 * Float64(sqrt(Float64(-log(u1))) * sqrt(2.0)))) + 0.5) end
function tmp = code(u1, u2) tmp = (1.0 * (0.16666666666666666 * (sqrt(-log(u1)) * sqrt(2.0)))) + 0.5; end
code[u1_, u2_] := N[(N[(1.0 * N[(0.16666666666666666 * N[(N[Sqrt[(-N[Log[u1], $MachinePrecision])], $MachinePrecision] * N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + 0.5), $MachinePrecision]
\begin{array}{l}
\\
1 \cdot \left(0.16666666666666666 \cdot \left(\sqrt{-\log u1} \cdot \sqrt{2}\right)\right) + 0.5
\end{array}
Initial program 99.4%
Taylor expanded in u1 around inf
*-commutativeN/A
lower-*.f64N/A
lower-sqrt.f64N/A
lower-sqrt.f64N/A
log-recN/A
lower-neg.f64N/A
lower-log.f6499.5
Applied rewrites99.5%
Taylor expanded in u2 around 0
Applied rewrites99.0%
lift-/.f64N/A
metadata-eval99.0
Applied rewrites99.0%
Final simplification99.0%
(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 99.4%
Taylor expanded in u2 around 0
+-commutativeN/A
*-commutativeN/A
associate-*r*N/A
lower-fma.f64N/A
lower-*.f64N/A
lower-sqrt.f64N/A
lower-sqrt.f64N/A
lower-log.f640.0
Applied rewrites0.0%
Applied rewrites98.9%
herbie shell --seed 2024327
(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))