
(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 10 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
(*
(log
(-
(/
1.0
(+
(/ 1.0 (+ (exp (* (/ 1.0 s) (PI))) 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}{\frac{1}{e^{\frac{1}{s} \cdot \mathsf{PI}\left(\right)} + 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 98.9%
lift-/.f32N/A
clear-numN/A
associate-/r/N/A
lower-*.f32N/A
lower-/.f3298.9
Applied rewrites98.9%
Final simplification98.9%
(FPCore (u s)
:precision binary32
(let* ((t_0 (/ -1.0 (- (exp (/ (PI) s)) -1.0))))
(*
(log
(-
-1.0
(/ -1.0 (- (* (- t_0 (/ -1.0 (- (exp (/ (- (PI)) s)) -1.0))) u) t_0))))
(- s))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{-1}{e^{\frac{\mathsf{PI}\left(\right)}{s}} - -1}\\
\log \left(-1 - \frac{-1}{\left(t\_0 - \frac{-1}{e^{\frac{-\mathsf{PI}\left(\right)}{s}} - -1}\right) \cdot u - t\_0}\right) \cdot \left(-s\right)
\end{array}
\end{array}
Initial program 98.9%
Final simplification98.9%
(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 98.9%
Taylor expanded in u around inf
*-commutativeN/A
lower-*.f32N/A
Applied rewrites97.5%
Final simplification97.5%
(FPCore (u s)
:precision binary32
(if (<= s 1.9999999774532045e-26)
(*
(log
(-
(/ 1.0 (fma -0.25 (fma (/ 1.0 s) (pow (/ 1.0 (PI)) -1.0) 0.0) 0.5))
1.0))
(- s))
(* (* u u) (/ (+ (/ (PI) u) (* -2.0 (PI))) (- u)))))\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;s \leq 1.9999999774532045 \cdot 10^{-26}:\\
\;\;\;\;\log \left(\frac{1}{\mathsf{fma}\left(-0.25, \mathsf{fma}\left(\frac{1}{s}, {\left(\frac{1}{\mathsf{PI}\left(\right)}\right)}^{-1}, 0\right), 0.5\right)} - 1\right) \cdot \left(-s\right)\\
\mathbf{else}:\\
\;\;\;\;\left(u \cdot u\right) \cdot \frac{\frac{\mathsf{PI}\left(\right)}{u} + -2 \cdot \mathsf{PI}\left(\right)}{-u}\\
\end{array}
\end{array}
if s < 1.99999998e-26Initial 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 rewrites14.7%
Applied rewrites23.0%
if 1.99999998e-26 < s Initial program 98.9%
Taylor expanded in s around -inf
Applied rewrites6.9%
Taylor expanded in u around -inf
Applied rewrites13.7%
Final simplification17.4%
(FPCore (u s)
:precision binary32
(let* ((t_0 (/ (PI) u)) (t_1 (/ (* (PI) (PI)) s)))
(if (<= s 4.999999999099794e-24)
(fma
(* (fma -4.0 (+ (/ t_1 u) t_1) (* (fma t_0 (/ (PI) s) t_1) 4.0)) (* u u))
-0.5
(* (fma (* (PI) u) -0.5 (* 0.25 (PI))) -4.0))
(* (* u u) (/ (+ t_0 (* -2.0 (PI))) (- u))))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{\mathsf{PI}\left(\right)}{u}\\
t_1 := \frac{\mathsf{PI}\left(\right) \cdot \mathsf{PI}\left(\right)}{s}\\
\mathbf{if}\;s \leq 4.999999999099794 \cdot 10^{-24}:\\
\;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(-4, \frac{t\_1}{u} + t\_1, \mathsf{fma}\left(t\_0, \frac{\mathsf{PI}\left(\right)}{s}, t\_1\right) \cdot 4\right) \cdot \left(u \cdot u\right), -0.5, \mathsf{fma}\left(\mathsf{PI}\left(\right) \cdot u, -0.5, 0.25 \cdot \mathsf{PI}\left(\right)\right) \cdot -4\right)\\
\mathbf{else}:\\
\;\;\;\;\left(u \cdot u\right) \cdot \frac{t\_0 + -2 \cdot \mathsf{PI}\left(\right)}{-u}\\
\end{array}
\end{array}
if s < 5e-24Initial program 99.0%
Taylor expanded in s around -inf
Applied rewrites7.5%
Applied rewrites12.0%
Taylor expanded in u around inf
Applied rewrites7.3%
if 5e-24 < s Initial program 98.8%
Taylor expanded in s around -inf
Applied rewrites6.9%
Taylor expanded in u around -inf
Applied rewrites14.4%
Final simplification11.1%
(FPCore (u s) :precision binary32 (if (<= s 1.0999999650920748e-20) 0.0 (* (* u u) (/ (+ (/ (PI) u) (* -2.0 (PI))) (- u)))))
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;s \leq 1.0999999650920748 \cdot 10^{-20}:\\
\;\;\;\;0\\
\mathbf{else}:\\
\;\;\;\;\left(u \cdot u\right) \cdot \frac{\frac{\mathsf{PI}\left(\right)}{u} + -2 \cdot \mathsf{PI}\left(\right)}{-u}\\
\end{array}
\end{array}
if s < 1.09999997e-20Initial program 99.1%
Taylor expanded in s around -inf
Applied rewrites7.1%
Taylor expanded in s around 0
Applied rewrites13.3%
if 1.09999997e-20 < s Initial program 98.7%
Taylor expanded in s around -inf
Applied rewrites7.4%
Taylor expanded in u around -inf
Applied rewrites15.7%
Final simplification14.3%
(FPCore (u s) :precision binary32 (if (<= s 1.0999999650920748e-20) 0.0 (* (- (* 2.0 (PI)) (/ (PI) u)) u)))
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;s \leq 1.0999999650920748 \cdot 10^{-20}:\\
\;\;\;\;0\\
\mathbf{else}:\\
\;\;\;\;\left(2 \cdot \mathsf{PI}\left(\right) - \frac{\mathsf{PI}\left(\right)}{u}\right) \cdot u\\
\end{array}
\end{array}
if s < 1.09999997e-20Initial program 99.1%
Taylor expanded in s around -inf
Applied rewrites7.1%
Taylor expanded in s around 0
Applied rewrites13.3%
if 1.09999997e-20 < s Initial program 98.7%
lift-neg.f32N/A
neg-sub0N/A
sub-negN/A
lift-neg.f32N/A
flip3-+N/A
lower-/.f32N/A
metadata-evalN/A
lower-+.f32N/A
lower-pow.f32N/A
metadata-evalN/A
lower-+.f32N/A
lower--.f32N/A
lower-*.f32N/A
lower-*.f3274.6
Applied rewrites74.6%
lift-+.f32N/A
+-lft-identity74.6
lift-+.f32N/A
+-lft-identity74.6
lower-/.f32N/A
lift-pow.f32N/A
sqr-powN/A
pow-prod-downN/A
lift-neg.f32N/A
lift-neg.f32N/A
sqr-negN/A
unpow-prod-downN/A
sqr-powN/A
lift--.f32N/A
lift-*.f32N/A
lift-*.f32N/A
distribute-rgt-out--N/A
--rgt-identityN/A
lift-neg.f32N/A
lift-neg.f32N/A
Applied rewrites98.6%
Taylor expanded in s around -inf
cancel-sign-sub-invN/A
metadata-evalN/A
distribute-lft-inN/A
distribute-rgt-out--N/A
metadata-evalN/A
associate-*r*N/A
*-commutativeN/A
associate-*r*N/A
metadata-evalN/A
associate-*r*N/A
metadata-evalN/A
lower-fma.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f32N/A
mul-1-negN/A
lower-neg.f32N/A
lower-PI.f3215.4
Applied rewrites15.4%
Taylor expanded in u around inf
Applied rewrites15.7%
(FPCore (u s) :precision binary32 (if (<= s 1.0999999650920748e-20) 0.0 (- (* (* (PI) u) 2.0) (PI))))
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;s \leq 1.0999999650920748 \cdot 10^{-20}:\\
\;\;\;\;0\\
\mathbf{else}:\\
\;\;\;\;\left(\mathsf{PI}\left(\right) \cdot u\right) \cdot 2 - \mathsf{PI}\left(\right)\\
\end{array}
\end{array}
if s < 1.09999997e-20Initial program 99.1%
Taylor expanded in s around -inf
Applied rewrites7.1%
Taylor expanded in s around 0
Applied rewrites13.3%
if 1.09999997e-20 < s Initial program 98.7%
lift-neg.f32N/A
neg-sub0N/A
sub-negN/A
lift-neg.f32N/A
flip3-+N/A
lower-/.f32N/A
metadata-evalN/A
lower-+.f32N/A
lower-pow.f32N/A
metadata-evalN/A
lower-+.f32N/A
lower--.f32N/A
lower-*.f32N/A
lower-*.f3274.6
Applied rewrites74.6%
lift-+.f32N/A
+-lft-identity74.6
lift-+.f32N/A
+-lft-identity74.6
lower-/.f32N/A
lift-pow.f32N/A
sqr-powN/A
pow-prod-downN/A
lift-neg.f32N/A
lift-neg.f32N/A
sqr-negN/A
unpow-prod-downN/A
sqr-powN/A
lift--.f32N/A
lift-*.f32N/A
lift-*.f32N/A
distribute-rgt-out--N/A
--rgt-identityN/A
lift-neg.f32N/A
lift-neg.f32N/A
Applied rewrites98.6%
Taylor expanded in s around -inf
cancel-sign-sub-invN/A
metadata-evalN/A
distribute-lft-inN/A
distribute-rgt-out--N/A
metadata-evalN/A
associate-*r*N/A
*-commutativeN/A
associate-*r*N/A
metadata-evalN/A
associate-*r*N/A
metadata-evalN/A
lower-fma.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f32N/A
mul-1-negN/A
lower-neg.f32N/A
lower-PI.f3215.4
Applied rewrites15.4%
Applied rewrites15.7%
Final simplification14.3%
(FPCore (u s) :precision binary32 (if (<= s 1.0999999650920748e-20) 0.0 (- (PI))))
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;s \leq 1.0999999650920748 \cdot 10^{-20}:\\
\;\;\;\;0\\
\mathbf{else}:\\
\;\;\;\;-\mathsf{PI}\left(\right)\\
\end{array}
\end{array}
if s < 1.09999997e-20Initial program 99.1%
Taylor expanded in s around -inf
Applied rewrites7.1%
Taylor expanded in s around 0
Applied rewrites13.3%
if 1.09999997e-20 < s Initial program 98.7%
Taylor expanded in u around 0
mul-1-negN/A
lower-neg.f32N/A
lower-PI.f3215.4
Applied rewrites15.4%
(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 98.9%
Taylor expanded in s around -inf
Applied rewrites7.3%
Taylor expanded in s around 0
Applied rewrites10.8%
herbie shell --seed 2024249
(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))))