
(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 (* (cos (* (* (PI) 2.0) u2)) (* 0.16666666666666666 (sqrt 2.0))) (sqrt (- (log u1))) 0.5))
\begin{array}{l}
\\
\mathsf{fma}\left(\cos \left(\left(\mathsf{PI}\left(\right) \cdot 2\right) \cdot u2\right) \cdot \left(0.16666666666666666 \cdot \sqrt{2}\right), \sqrt{-\log u1}, 0.5\right)
\end{array}
Initial program 99.4%
lift-+.f64N/A
flip3-+N/A
clear-numN/A
lower-/.f64N/A
Applied rewrites99.3%
Applied rewrites99.6%
Final simplification99.6%
(FPCore (u1 u2) :precision binary64 (fma (* (sqrt (* -2.0 (log u1))) (cos (* (* (PI) 2.0) u2))) 0.16666666666666666 0.5))
\begin{array}{l}
\\
\mathsf{fma}\left(\sqrt{-2 \cdot \log u1} \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 (* (fma (* u2 u2) (* -0.3333333333333333 (* (PI) (PI))) 0.16666666666666666) (sqrt 2.0)) (sqrt (- (log u1))) 0.5))
\begin{array}{l}
\\
\mathsf{fma}\left(\mathsf{fma}\left(u2 \cdot u2, -0.3333333333333333 \cdot \left(\mathsf{PI}\left(\right) \cdot \mathsf{PI}\left(\right)\right), 0.16666666666666666\right) \cdot \sqrt{2}, \sqrt{-\log u1}, 0.5\right)
\end{array}
Initial program 99.4%
lift-+.f64N/A
flip3-+N/A
clear-numN/A
lower-/.f64N/A
Applied rewrites99.3%
Applied rewrites99.6%
Taylor expanded in u2 around 0
*-commutativeN/A
associate-*r*N/A
*-commutativeN/A
associate-*r*N/A
associate-*r*N/A
distribute-rgt-outN/A
lower-*.f64N/A
lower-sqrt.f64N/A
lower-fma.f64N/A
unpow2N/A
lower-*.f64N/A
*-commutativeN/A
lower-*.f64N/A
unpow2N/A
lower-*.f64N/A
lower-PI.f64N/A
lower-PI.f6499.4
Applied rewrites99.4%
Final simplification99.4%
(FPCore (u1 u2) :precision binary64 (+ (* (fma (* (* u2 u2) -2.0) (* (PI) (PI)) 1.0) (* (sqrt (* -2.0 (log u1))) 0.16666666666666666)) 0.5))
\begin{array}{l}
\\
\mathsf{fma}\left(\left(u2 \cdot u2\right) \cdot -2, \mathsf{PI}\left(\right) \cdot \mathsf{PI}\left(\right), 1\right) \cdot \left(\sqrt{-2 \cdot \log u1} \cdot 0.16666666666666666\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
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.f6499.3
Applied rewrites99.3%
lift-*.f64N/A
lift-/.f64N/A
metadata-evalN/A
*-commutativeN/A
lower-*.f6499.3
Applied rewrites99.2%
Final simplification99.2%
(FPCore (u1 u2) :precision binary64 (fma (* 0.16666666666666666 (sqrt 2.0)) (sqrt (- (log u1))) 0.5))
double code(double u1, double u2) {
return fma((0.16666666666666666 * sqrt(2.0)), sqrt(-log(u1)), 0.5);
}
function code(u1, u2) return fma(Float64(0.16666666666666666 * sqrt(2.0)), sqrt(Float64(-log(u1))), 0.5) end
code[u1_, u2_] := N[(N[(0.16666666666666666 * N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision] * N[Sqrt[(-N[Log[u1], $MachinePrecision])], $MachinePrecision] + 0.5), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(0.16666666666666666 \cdot \sqrt{2}, \sqrt{-\log u1}, 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 rewrites99.1%
Final simplification99.1%
(FPCore (u1 u2) :precision binary64 (fma (* (sqrt (- (log u1))) 0.16666666666666666) (sqrt 2.0) 0.5))
double code(double u1, double u2) {
return fma((sqrt(-log(u1)) * 0.16666666666666666), sqrt(2.0), 0.5);
}
function code(u1, u2) return fma(Float64(sqrt(Float64(-log(u1))) * 0.16666666666666666), sqrt(2.0), 0.5) end
code[u1_, u2_] := N[(N[(N[Sqrt[(-N[Log[u1], $MachinePrecision])], $MachinePrecision] * 0.16666666666666666), $MachinePrecision] * N[Sqrt[2.0], $MachinePrecision] + 0.5), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\sqrt{-\log u1} \cdot 0.16666666666666666, \sqrt{2}, 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 rewrites99.0%
Final simplification99.0%
(FPCore (u1 u2) :precision binary64 (fma (sqrt (* -2.0 (log u1))) 0.16666666666666666 0.5))
double code(double u1, double u2) {
return fma(sqrt((-2.0 * log(u1))), 0.16666666666666666, 0.5);
}
function code(u1, u2) return fma(sqrt(Float64(-2.0 * log(u1))), 0.16666666666666666, 0.5) end
code[u1_, u2_] := N[(N[Sqrt[N[(-2.0 * N[Log[u1], $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * 0.16666666666666666 + 0.5), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\sqrt{-2 \cdot \log u1}, 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%
Final simplification98.9%
herbie shell --seed 2024248
(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))