
(FPCore (u s)
:precision binary32
(let* ((t_0 (/ 1.0 (+ 1.0 (exp (/ (PI) s))))))
(*
(- s)
(log
(-
(/ 1.0 (+ (* u (- (/ 1.0 (+ 1.0 (exp (/ (- (PI)) s)))) t_0)) t_0))
1.0)))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{1}{1 + e^{\frac{\mathsf{PI}\left(\right)}{s}}}\\
\left(-s\right) \cdot \log \left(\frac{1}{u \cdot \left(\frac{1}{1 + e^{\frac{-\mathsf{PI}\left(\right)}{s}}} - t\_0\right) + t\_0} - 1\right)
\end{array}
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 9 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (u s)
:precision binary32
(let* ((t_0 (/ 1.0 (+ 1.0 (exp (/ (PI) s))))))
(*
(- s)
(log
(-
(/ 1.0 (+ (* u (- (/ 1.0 (+ 1.0 (exp (/ (- (PI)) s)))) t_0)) t_0))
1.0)))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{1}{1 + e^{\frac{\mathsf{PI}\left(\right)}{s}}}\\
\left(-s\right) \cdot \log \left(\frac{1}{u \cdot \left(\frac{1}{1 + e^{\frac{-\mathsf{PI}\left(\right)}{s}}} - t\_0\right) + t\_0} - 1\right)
\end{array}
\end{array}
(FPCore (u s)
:precision binary32
(let* ((t_0 (/ 1.0 (+ (exp (/ (PI) s)) 1.0))))
(*
(log
(-
(/ 1.0 (+ (* (- (/ 1.0 (+ (exp (/ (- (PI)) s)) 1.0)) t_0) u) t_0))
1.0))
(- s))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{1}{e^{\frac{\mathsf{PI}\left(\right)}{s}} + 1}\\
\log \left(\frac{1}{\left(\frac{1}{e^{\frac{-\mathsf{PI}\left(\right)}{s}} + 1} - t\_0\right) \cdot u + t\_0} - 1\right) \cdot \left(-s\right)
\end{array}
\end{array}
Initial program 99.0%
Final simplification99.0%
(FPCore (u s)
:precision binary32
(*
(log
(-
(/
(/ 1.0 u)
(- (/ 1.0 (+ (exp (/ (- (PI)) s)) 1.0)) (/ 1.0 (+ (exp (/ (PI) s)) 1.0))))
1.0))
(- s)))\begin{array}{l}
\\
\log \left(\frac{\frac{1}{u}}{\frac{1}{e^{\frac{-\mathsf{PI}\left(\right)}{s}} + 1} - \frac{1}{e^{\frac{\mathsf{PI}\left(\right)}{s}} + 1}} - 1\right) \cdot \left(-s\right)
\end{array}
Initial program 99.0%
Taylor expanded in s around inf
distribute-rgt-out--N/A
metadata-evalN/A
associate-*r*N/A
metadata-evalN/A
distribute-rgt-neg-inN/A
associate-*r*N/A
metadata-evalN/A
distribute-rgt-out--N/A
distribute-neg-fracN/A
distribute-neg-frac2N/A
mul-1-negN/A
distribute-rgt-out--N/A
metadata-evalN/A
associate-*r*N/A
*-commutativeN/A
times-fracN/A
metadata-evalN/A
lower-*.f32N/A
Applied rewrites4.7%
Taylor expanded in u around inf
lower--.f32N/A
Applied rewrites97.9%
Final simplification97.9%
(FPCore (u s)
:precision binary32
(let* ((t_0 (fma (* -0.5 (PI)) u (* 0.25 (PI)))))
(*
(log
(- 1.0 (/ (- (fma (/ (pow t_0 2.0) s) -8.0 (/ 0.0 s)) (* 4.0 t_0)) s)))
(- s))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \mathsf{fma}\left(-0.5 \cdot \mathsf{PI}\left(\right), u, 0.25 \cdot \mathsf{PI}\left(\right)\right)\\
\log \left(1 - \frac{\mathsf{fma}\left(\frac{{t\_0}^{2}}{s}, -8, \frac{0}{s}\right) - 4 \cdot t\_0}{s}\right) \cdot \left(-s\right)
\end{array}
\end{array}
Initial program 99.0%
Taylor expanded in s around inf
distribute-rgt-out--N/A
metadata-evalN/A
associate-*r*N/A
metadata-evalN/A
distribute-rgt-neg-inN/A
associate-*r*N/A
metadata-evalN/A
distribute-rgt-out--N/A
distribute-neg-fracN/A
distribute-neg-frac2N/A
mul-1-negN/A
distribute-rgt-out--N/A
metadata-evalN/A
associate-*r*N/A
*-commutativeN/A
times-fracN/A
metadata-evalN/A
lower-*.f32N/A
Applied rewrites4.7%
Taylor expanded in u around inf
lower--.f32N/A
Applied rewrites97.9%
Taylor expanded in s around -inf
mul-1-negN/A
unsub-negN/A
lower--.f32N/A
Applied rewrites12.1%
Final simplification12.4%
(FPCore (u s)
:precision binary32
(*
(log
(-
(-
(fma (/ (fma (* (* 0.5 (PI)) u) 0.5 (* 0.25 (PI))) s) -8.0 2.0)
(* -0.25 (/ (* 12.0 (PI)) s)))
1.0))
(- s)))\begin{array}{l}
\\
\log \left(\left(\mathsf{fma}\left(\frac{\mathsf{fma}\left(\left(0.5 \cdot \mathsf{PI}\left(\right)\right) \cdot u, 0.5, 0.25 \cdot \mathsf{PI}\left(\right)\right)}{s}, -8, 2\right) - -0.25 \cdot \frac{12 \cdot \mathsf{PI}\left(\right)}{s}\right) - 1\right) \cdot \left(-s\right)
\end{array}
Initial program 99.0%
Applied rewrites97.9%
Taylor expanded in s around inf
lower--.f32N/A
Applied rewrites20.9%
Final simplification21.3%
(FPCore (u s) :precision binary32 (if (<= s 1.199999978942004e-13) (* (log (- (/ 1.0 (fma -0.25 (/ (PI) s) 0.5)) 1.0)) (- s)) (* -4.0 (* (* (- (/ 0.25 u) 0.5) u) (PI)))))
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;s \leq 1.199999978942004 \cdot 10^{-13}:\\
\;\;\;\;\log \left(\frac{1}{\mathsf{fma}\left(-0.25, \frac{\mathsf{PI}\left(\right)}{s}, 0.5\right)} - 1\right) \cdot \left(-s\right)\\
\mathbf{else}:\\
\;\;\;\;-4 \cdot \left(\left(\left(\frac{0.25}{u} - 0.5\right) \cdot u\right) \cdot \mathsf{PI}\left(\right)\right)\\
\end{array}
\end{array}
if s < 1.19999998e-13Initial program 99.0%
Taylor expanded in s around -inf
mul-1-negN/A
unsub-negN/A
lower--.f32N/A
lower-/.f32N/A
Applied rewrites-0.0%
Taylor expanded in u around 0
Applied rewrites11.9%
if 1.19999998e-13 < s Initial program 99.0%
lift-/.f32N/A
lift-PI.f32N/A
add-cube-cbrtN/A
associate-/l*N/A
lower-*.f32N/A
pow2N/A
lower-pow.f32N/A
lift-PI.f32N/A
lower-cbrt.f32N/A
lower-/.f32N/A
lift-PI.f32N/A
lower-cbrt.f3299.0
Applied rewrites99.0%
Taylor expanded in s around -inf
*-commutativeN/A
lower-*.f32N/A
cancel-sign-sub-invN/A
metadata-evalN/A
distribute-rgt-out--N/A
metadata-evalN/A
*-commutativeN/A
associate-*r*N/A
*-commutativeN/A
distribute-rgt-outN/A
lower-*.f32N/A
lower-PI.f32N/A
lower-fma.f3218.5
Applied rewrites18.4%
Taylor expanded in u around inf
Applied rewrites18.6%
Final simplification14.4%
(FPCore (u s) :precision binary32 (* -4.0 (* (* (- (/ 0.25 u) 0.5) u) (PI))))
\begin{array}{l}
\\
-4 \cdot \left(\left(\left(\frac{0.25}{u} - 0.5\right) \cdot u\right) \cdot \mathsf{PI}\left(\right)\right)
\end{array}
Initial program 99.0%
lift-/.f32N/A
lift-PI.f32N/A
add-cube-cbrtN/A
associate-/l*N/A
lower-*.f32N/A
pow2N/A
lower-pow.f32N/A
lift-PI.f32N/A
lower-cbrt.f32N/A
lower-/.f32N/A
lift-PI.f32N/A
lower-cbrt.f3299.0
Applied rewrites99.0%
Taylor expanded in s around -inf
*-commutativeN/A
lower-*.f32N/A
cancel-sign-sub-invN/A
metadata-evalN/A
distribute-rgt-out--N/A
metadata-evalN/A
*-commutativeN/A
associate-*r*N/A
*-commutativeN/A
distribute-rgt-outN/A
lower-*.f32N/A
lower-PI.f32N/A
lower-fma.f3212.1
Applied rewrites12.1%
Taylor expanded in u around inf
Applied rewrites12.2%
Final simplification12.2%
(FPCore (u s) :precision binary32 (- (* (* (PI) u) 2.0) (PI)))
\begin{array}{l}
\\
\left(\mathsf{PI}\left(\right) \cdot u\right) \cdot 2 - \mathsf{PI}\left(\right)
\end{array}
Initial program 99.0%
lift-/.f32N/A
lift-PI.f32N/A
add-cube-cbrtN/A
associate-/l*N/A
lower-*.f32N/A
pow2N/A
lower-pow.f32N/A
lift-PI.f32N/A
lower-cbrt.f32N/A
lower-/.f32N/A
lift-PI.f32N/A
lower-cbrt.f3299.0
Applied rewrites99.0%
Taylor expanded in s around -inf
*-commutativeN/A
lower-*.f32N/A
cancel-sign-sub-invN/A
metadata-evalN/A
distribute-rgt-out--N/A
metadata-evalN/A
*-commutativeN/A
associate-*r*N/A
*-commutativeN/A
distribute-rgt-outN/A
lower-*.f32N/A
lower-PI.f32N/A
lower-fma.f3212.1
Applied rewrites12.1%
Taylor expanded in u around 0
Applied rewrites12.2%
(FPCore (u s) :precision binary32 (- (PI)))
\begin{array}{l}
\\
-\mathsf{PI}\left(\right)
\end{array}
Initial program 99.0%
Taylor expanded in u around 0
mul-1-negN/A
lower-neg.f32N/A
lower-PI.f3212.1
Applied rewrites12.1%
(FPCore (u s) :precision binary32 0.0)
float code(float u, float s) {
return 0.0f;
}
real(4) function code(u, s)
real(4), intent (in) :: u
real(4), intent (in) :: s
code = 0.0e0
end function
function code(u, s) return Float32(0.0) end
function tmp = code(u, s) tmp = single(0.0); end
\begin{array}{l}
\\
0
\end{array}
Initial program 99.0%
Taylor expanded in s around -inf
mul-1-negN/A
unsub-negN/A
lower--.f32N/A
lower-/.f32N/A
Applied rewrites-0.0%
lift--.f32N/A
Applied rewrites1.1%
Taylor expanded in s around inf
mul-1-negN/A
*-commutativeN/A
distribute-lft-neg-inN/A
exp-negN/A
rem-exp-logN/A
metadata-evalN/A
metadata-evalN/A
metadata-evalN/A
metadata-evalN/A
lower-*.f3210.1
Applied rewrites10.1%
Applied rewrites10.1%
herbie shell --seed 2024332
(FPCore (u s)
:name "Sample trimmed logistic on [-pi, pi]"
:precision binary32
:pre (and (and (<= 2.328306437e-10 u) (<= u 1.0)) (and (<= 0.0 s) (<= s 1.0651631)))
(* (- s) (log (- (/ 1.0 (+ (* u (- (/ 1.0 (+ 1.0 (exp (/ (- (PI)) s)))) (/ 1.0 (+ 1.0 (exp (/ (PI) s)))))) (/ 1.0 (+ 1.0 (exp (/ (PI) s)))))) 1.0))))