
(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
(let* ((t_0 (/ 1.0 (+ (exp (/ (PI) s)) 1.0)))
(t_1 (* (fma 0.5 u -0.25) (PI))))
(if (<=
(*
(log
(-
(/ 1.0 (+ (* (- (/ 1.0 (+ (exp (/ (- (PI)) s)) 1.0)) t_0) u) t_0))
1.0))
(- s))
-1.0000000195414814e-25)
(* -4.0 (* (* (- (/ 0.25 u) 0.5) u) (PI)))
(*
(log
(fma (/ t_1 s) -4.0 (- 1.0 (/ (fma -8.0 (pow t_1 2.0) 0.0) (* s s)))))
(- s)))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{1}{e^{\frac{\mathsf{PI}\left(\right)}{s}} + 1}\\
t_1 := \mathsf{fma}\left(0.5, u, -0.25\right) \cdot \mathsf{PI}\left(\right)\\
\mathbf{if}\;\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) \leq -1.0000000195414814 \cdot 10^{-25}:\\
\;\;\;\;-4 \cdot \left(\left(\left(\frac{0.25}{u} - 0.5\right) \cdot u\right) \cdot \mathsf{PI}\left(\right)\right)\\
\mathbf{else}:\\
\;\;\;\;\log \left(\mathsf{fma}\left(\frac{t\_1}{s}, -4, 1 - \frac{\mathsf{fma}\left(-8, {t\_1}^{2}, 0\right)}{s \cdot s}\right)\right) \cdot \left(-s\right)\\
\end{array}
\end{array}
if (*.f32 (neg.f32 s) (log.f32 (-.f32 (/.f32 #s(literal 1 binary32) (+.f32 (*.f32 u (-.f32 (/.f32 #s(literal 1 binary32) (+.f32 #s(literal 1 binary32) (exp.f32 (/.f32 (neg.f32 (PI.f32)) s)))) (/.f32 #s(literal 1 binary32) (+.f32 #s(literal 1 binary32) (exp.f32 (/.f32 (PI.f32) s)))))) (/.f32 #s(literal 1 binary32) (+.f32 #s(literal 1 binary32) (exp.f32 (/.f32 (PI.f32) s)))))) #s(literal 1 binary32)))) < -1.00000002e-25Initial program 99.1%
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.f3299.1
Applied rewrites99.1%
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.f3214.3
Applied rewrites14.3%
Taylor expanded in u around inf
Applied rewrites14.3%
if -1.00000002e-25 < (*.f32 (neg.f32 s) (log.f32 (-.f32 (/.f32 #s(literal 1 binary32) (+.f32 (*.f32 u (-.f32 (/.f32 #s(literal 1 binary32) (+.f32 #s(literal 1 binary32) (exp.f32 (/.f32 (neg.f32 (PI.f32)) s)))) (/.f32 #s(literal 1 binary32) (+.f32 #s(literal 1 binary32) (exp.f32 (/.f32 (PI.f32) s)))))) (/.f32 #s(literal 1 binary32) (+.f32 #s(literal 1 binary32) (exp.f32 (/.f32 (PI.f32) s)))))) #s(literal 1 binary32)))) Initial program 98.8%
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 rewrites-0.0%
Taylor expanded in u around inf
lower--.f32N/A
Applied rewrites98.8%
Applied rewrites98.8%
Taylor expanded in s around inf
Applied rewrites7.9%
Final simplification11.5%
(FPCore (u s)
:precision binary32
(let* ((t_0 (/ 1.0 (+ (exp (/ (PI) s)) 1.0))))
(if (<=
(*
(log
(-
(/ 1.0 (+ (* (- (/ 1.0 (+ (exp (/ (- (PI)) s)) 1.0)) t_0) u) t_0))
1.0))
(- s))
-1.9999999920083944e-11)
(* -4.0 (* (* (- (/ 0.25 u) 0.5) u) (PI)))
(* (fma (pow (PI) 0.5) (* (* -0.5 u) (sqrt (PI))) (* 0.25 (PI))) -4.0))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{1}{e^{\frac{\mathsf{PI}\left(\right)}{s}} + 1}\\
\mathbf{if}\;\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) \leq -1.9999999920083944 \cdot 10^{-11}:\\
\;\;\;\;-4 \cdot \left(\left(\left(\frac{0.25}{u} - 0.5\right) \cdot u\right) \cdot \mathsf{PI}\left(\right)\right)\\
\mathbf{else}:\\
\;\;\;\;\mathsf{fma}\left({\mathsf{PI}\left(\right)}^{0.5}, \left(-0.5 \cdot u\right) \cdot \sqrt{\mathsf{PI}\left(\right)}, 0.25 \cdot \mathsf{PI}\left(\right)\right) \cdot -4\\
\end{array}
\end{array}
if (*.f32 (neg.f32 s) (log.f32 (-.f32 (/.f32 #s(literal 1 binary32) (+.f32 (*.f32 u (-.f32 (/.f32 #s(literal 1 binary32) (+.f32 #s(literal 1 binary32) (exp.f32 (/.f32 (neg.f32 (PI.f32)) s)))) (/.f32 #s(literal 1 binary32) (+.f32 #s(literal 1 binary32) (exp.f32 (/.f32 (PI.f32) s)))))) (/.f32 #s(literal 1 binary32) (+.f32 #s(literal 1 binary32) (exp.f32 (/.f32 (PI.f32) s)))))) #s(literal 1 binary32)))) < -1.99999999e-11Initial 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.f3218.9
Applied rewrites18.7%
Taylor expanded in u around inf
Applied rewrites19.0%
if -1.99999999e-11 < (*.f32 (neg.f32 s) (log.f32 (-.f32 (/.f32 #s(literal 1 binary32) (+.f32 (*.f32 u (-.f32 (/.f32 #s(literal 1 binary32) (+.f32 #s(literal 1 binary32) (exp.f32 (/.f32 (neg.f32 (PI.f32)) s)))) (/.f32 #s(literal 1 binary32) (+.f32 #s(literal 1 binary32) (exp.f32 (/.f32 (PI.f32) s)))))) (/.f32 #s(literal 1 binary32) (+.f32 #s(literal 1 binary32) (exp.f32 (/.f32 (PI.f32) s)))))) #s(literal 1 binary32)))) 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.f328.4
Applied rewrites8.4%
Applied rewrites8.4%
Applied rewrites8.4%
Final simplification12.1%
(FPCore (u s)
:precision binary32
(*
(log
(-
(/
1.0
(*
(- (/ 1.0 (+ (exp (/ (- (PI)) s)) 1.0)) (/ 1.0 (+ (exp (/ (PI) s)) 1.0)))
u))
1.0))
(- s)))\begin{array}{l}
\\
\log \left(\frac{1}{\left(\frac{1}{e^{\frac{-\mathsf{PI}\left(\right)}{s}} + 1} - \frac{1}{e^{\frac{\mathsf{PI}\left(\right)}{s}} + 1}\right) \cdot u} - 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%
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
Applied rewrites13.3%
Final simplification11.5%
(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 (* (+ (* (* -0.5 (PI)) u) (* 0.25 (PI))) -4.0))
\begin{array}{l}
\\
\left(\left(-0.5 \cdot \mathsf{PI}\left(\right)\right) \cdot u + 0.25 \cdot \mathsf{PI}\left(\right)\right) \cdot -4
\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%
Applied rewrites12.2%
(FPCore (u s) :precision binary32 (* (* (+ (* -0.5 u) 0.25) (PI)) -4.0))
\begin{array}{l}
\\
\left(\left(-0.5 \cdot u + 0.25\right) \cdot \mathsf{PI}\left(\right)\right) \cdot -4
\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%
Applied rewrites12.2%
Final simplification12.2%
(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%
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))))