
(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)))))
float code(float u, float s) {
float t_0 = 1.0f / (1.0f + expf((((float) M_PI) / s)));
return -s * logf(((1.0f / ((u * ((1.0f / (1.0f + expf((-((float) M_PI) / s)))) - t_0)) + t_0)) - 1.0f));
}
function code(u, s) t_0 = Float32(Float32(1.0) / Float32(Float32(1.0) + exp(Float32(Float32(pi) / s)))) return Float32(Float32(-s) * log(Float32(Float32(Float32(1.0) / Float32(Float32(u * Float32(Float32(Float32(1.0) / Float32(Float32(1.0) + exp(Float32(Float32(-Float32(pi)) / s)))) - t_0)) + t_0)) - Float32(1.0)))) end
function tmp = code(u, s) t_0 = single(1.0) / (single(1.0) + exp((single(pi) / s))); tmp = -s * log(((single(1.0) / ((u * ((single(1.0) / (single(1.0) + exp((-single(pi) / s)))) - t_0)) + t_0)) - single(1.0))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{1}{1 + e^{\frac{\pi}{s}}}\\
\left(-s\right) \cdot \log \left(\frac{1}{u \cdot \left(\frac{1}{1 + e^{\frac{-\pi}{s}}} - t\_0\right) + t\_0} - 1\right)
\end{array}
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 14 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)))))
float code(float u, float s) {
float t_0 = 1.0f / (1.0f + expf((((float) M_PI) / s)));
return -s * logf(((1.0f / ((u * ((1.0f / (1.0f + expf((-((float) M_PI) / s)))) - t_0)) + t_0)) - 1.0f));
}
function code(u, s) t_0 = Float32(Float32(1.0) / Float32(Float32(1.0) + exp(Float32(Float32(pi) / s)))) return Float32(Float32(-s) * log(Float32(Float32(Float32(1.0) / Float32(Float32(u * Float32(Float32(Float32(1.0) / Float32(Float32(1.0) + exp(Float32(Float32(-Float32(pi)) / s)))) - t_0)) + t_0)) - Float32(1.0)))) end
function tmp = code(u, s) t_0 = single(1.0) / (single(1.0) + exp((single(pi) / s))); tmp = -s * log(((single(1.0) / ((u * ((single(1.0) / (single(1.0) + exp((-single(pi) / s)))) - t_0)) + t_0)) - single(1.0))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{1}{1 + e^{\frac{\pi}{s}}}\\
\left(-s\right) \cdot \log \left(\frac{1}{u \cdot \left(\frac{1}{1 + e^{\frac{-\pi}{s}}} - t\_0\right) + t\_0} - 1\right)
\end{array}
\end{array}
(FPCore (u s)
:precision binary32
(let* ((t_0
(+
(/ u (+ 1.0 (exp (/ PI (- s)))))
(/ (- 1.0 u) (+ 1.0 (exp (/ PI s)))))))
(*
(- s)
(log (/ (+ (pow t_0 -3.0) -1.0) (+ (pow t_0 -2.0) (+ 1.0 (/ 1.0 t_0))))))))
float code(float u, float s) {
float t_0 = (u / (1.0f + expf((((float) M_PI) / -s)))) + ((1.0f - u) / (1.0f + expf((((float) M_PI) / s))));
return -s * logf(((powf(t_0, -3.0f) + -1.0f) / (powf(t_0, -2.0f) + (1.0f + (1.0f / t_0)))));
}
function code(u, s) t_0 = Float32(Float32(u / Float32(Float32(1.0) + exp(Float32(Float32(pi) / Float32(-s))))) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(1.0) + exp(Float32(Float32(pi) / s))))) return Float32(Float32(-s) * log(Float32(Float32((t_0 ^ Float32(-3.0)) + Float32(-1.0)) / Float32((t_0 ^ Float32(-2.0)) + Float32(Float32(1.0) + Float32(Float32(1.0) / t_0)))))) end
function tmp = code(u, s) t_0 = (u / (single(1.0) + exp((single(pi) / -s)))) + ((single(1.0) - u) / (single(1.0) + exp((single(pi) / s)))); tmp = -s * log((((t_0 ^ single(-3.0)) + single(-1.0)) / ((t_0 ^ single(-2.0)) + (single(1.0) + (single(1.0) / t_0))))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{u}{1 + e^{\frac{\pi}{-s}}} + \frac{1 - u}{1 + e^{\frac{\pi}{s}}}\\
\left(-s\right) \cdot \log \left(\frac{{t\_0}^{-3} + -1}{{t\_0}^{-2} + \left(1 + \frac{1}{t\_0}\right)}\right)
\end{array}
\end{array}
Initial program 99.0%
Simplified99.0%
Applied egg-rr99.1%
Final simplification99.1%
(FPCore (u s)
:precision binary32
(let* ((t_0
(+
(/ u (+ 1.0 (exp (/ PI (- s)))))
(/ (- 1.0 u) (+ 1.0 (exp (/ PI s)))))))
(*
(- s)
(log (/ 1.0 (* (/ 1.0 (+ (pow t_0 -2.0) -1.0)) (+ 1.0 (/ 1.0 t_0))))))))
float code(float u, float s) {
float t_0 = (u / (1.0f + expf((((float) M_PI) / -s)))) + ((1.0f - u) / (1.0f + expf((((float) M_PI) / s))));
return -s * logf((1.0f / ((1.0f / (powf(t_0, -2.0f) + -1.0f)) * (1.0f + (1.0f / t_0)))));
}
function code(u, s) t_0 = Float32(Float32(u / Float32(Float32(1.0) + exp(Float32(Float32(pi) / Float32(-s))))) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(1.0) + exp(Float32(Float32(pi) / s))))) return Float32(Float32(-s) * log(Float32(Float32(1.0) / Float32(Float32(Float32(1.0) / Float32((t_0 ^ Float32(-2.0)) + Float32(-1.0))) * Float32(Float32(1.0) + Float32(Float32(1.0) / t_0)))))) end
function tmp = code(u, s) t_0 = (u / (single(1.0) + exp((single(pi) / -s)))) + ((single(1.0) - u) / (single(1.0) + exp((single(pi) / s)))); tmp = -s * log((single(1.0) / ((single(1.0) / ((t_0 ^ single(-2.0)) + single(-1.0))) * (single(1.0) + (single(1.0) / t_0))))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{u}{1 + e^{\frac{\pi}{-s}}} + \frac{1 - u}{1 + e^{\frac{\pi}{s}}}\\
\left(-s\right) \cdot \log \left(\frac{1}{\frac{1}{{t\_0}^{-2} + -1} \cdot \left(1 + \frac{1}{t\_0}\right)}\right)
\end{array}
\end{array}
Initial program 99.0%
Simplified99.0%
Applied egg-rr99.1%
clear-numN/A
/-lowering-/.f32N/A
Applied egg-rr99.0%
flip-+N/A
associate-/r/N/A
*-lowering-*.f32N/A
Applied egg-rr99.1%
Final simplification99.1%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(/
1.0
(/
1.0
(+
-1.0
(/
1.0
(+
(/ u (+ 1.0 (exp (/ PI (- s)))))
(/ (- 1.0 u) (+ 1.0 (exp (/ PI s))))))))))))
float code(float u, float s) {
return -s * logf((1.0f / (1.0f / (-1.0f + (1.0f / ((u / (1.0f + expf((((float) M_PI) / -s)))) + ((1.0f - u) / (1.0f + expf((((float) M_PI) / s))))))))));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(1.0) / Float32(Float32(1.0) / Float32(Float32(-1.0) + Float32(Float32(1.0) / Float32(Float32(u / Float32(Float32(1.0) + exp(Float32(Float32(pi) / Float32(-s))))) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(1.0) + exp(Float32(Float32(pi) / s))))))))))) end
function tmp = code(u, s) tmp = -s * log((single(1.0) / (single(1.0) / (single(-1.0) + (single(1.0) / ((u / (single(1.0) + exp((single(pi) / -s)))) + ((single(1.0) - u) / (single(1.0) + exp((single(pi) / s)))))))))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(\frac{1}{\frac{1}{-1 + \frac{1}{\frac{u}{1 + e^{\frac{\pi}{-s}}} + \frac{1 - u}{1 + e^{\frac{\pi}{s}}}}}}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Applied egg-rr99.1%
clear-numN/A
/-lowering-/.f32N/A
Applied egg-rr99.0%
Final simplification99.0%
(FPCore (u s)
:precision binary32
(*
(- s)
(log
(+
-1.0
(/
1.0
(+
(/ u (+ 1.0 (exp (/ PI (- s)))))
(/ (- 1.0 u) (+ 1.0 (exp (/ PI s))))))))))
float code(float u, float s) {
return -s * logf((-1.0f + (1.0f / ((u / (1.0f + expf((((float) M_PI) / -s)))) + ((1.0f - u) / (1.0f + expf((((float) M_PI) / s))))))));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(-1.0) + Float32(Float32(1.0) / Float32(Float32(u / Float32(Float32(1.0) + exp(Float32(Float32(pi) / Float32(-s))))) + Float32(Float32(Float32(1.0) - u) / Float32(Float32(1.0) + exp(Float32(Float32(pi) / s))))))))) end
function tmp = code(u, s) tmp = -s * log((single(-1.0) + (single(1.0) / ((u / (single(1.0) + exp((single(pi) / -s)))) + ((single(1.0) - u) / (single(1.0) + exp((single(pi) / s)))))))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(-1 + \frac{1}{\frac{u}{1 + e^{\frac{\pi}{-s}}} + \frac{1 - u}{1 + e^{\frac{\pi}{s}}}}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Applied egg-rr99.1%
metadata-evalN/A
pow-powN/A
inv-powN/A
metadata-evalN/A
Applied egg-rr99.0%
Final simplification99.0%
(FPCore (u s) :precision binary32 (* (- s) (log (+ -1.0 (/ (+ 1.0 (exp (/ PI (- s)))) u)))))
float code(float u, float s) {
return -s * logf((-1.0f + ((1.0f + expf((((float) M_PI) / -s))) / u)));
}
function code(u, s) return Float32(Float32(-s) * log(Float32(Float32(-1.0) + Float32(Float32(Float32(1.0) + exp(Float32(Float32(pi) / Float32(-s)))) / u)))) end
function tmp = code(u, s) tmp = -s * log((single(-1.0) + ((single(1.0) + exp((single(pi) / -s))) / u))); end
\begin{array}{l}
\\
\left(-s\right) \cdot \log \left(-1 + \frac{1 + e^{\frac{\pi}{-s}}}{u}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around -inf
mul-1-negN/A
unsub-negN/A
--lowering--.f32N/A
/-lowering-/.f32N/A
Simplified93.5%
Taylor expanded in s around 0
/-lowering-/.f32N/A
+-lowering-+.f32N/A
exp-lowering-exp.f32N/A
neg-sub0N/A
--lowering--.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f3297.8%
Simplified97.8%
Final simplification97.8%
(FPCore (u s)
:precision binary32
(let* ((t_0 (+ 1.0 (/ PI s))))
(-
(* u (* 2.0 (+ (/ PI t_0) (/ (/ (* u (* PI PI)) s) (* t_0 t_0)))))
(* s (log1p (/ PI s))))))
float code(float u, float s) {
float t_0 = 1.0f + (((float) M_PI) / s);
return (u * (2.0f * ((((float) M_PI) / t_0) + (((u * (((float) M_PI) * ((float) M_PI))) / s) / (t_0 * t_0))))) - (s * log1pf((((float) M_PI) / s)));
}
function code(u, s) t_0 = Float32(Float32(1.0) + Float32(Float32(pi) / s)) return Float32(Float32(u * Float32(Float32(2.0) * Float32(Float32(Float32(pi) / t_0) + Float32(Float32(Float32(u * Float32(Float32(pi) * Float32(pi))) / s) / Float32(t_0 * t_0))))) - Float32(s * log1p(Float32(Float32(pi) / s)))) end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := 1 + \frac{\pi}{s}\\
u \cdot \left(2 \cdot \left(\frac{\pi}{t\_0} + \frac{\frac{u \cdot \left(\pi \cdot \pi\right)}{s}}{t\_0 \cdot t\_0}\right)\right) - s \cdot \mathsf{log1p}\left(\frac{\pi}{s}\right)
\end{array}
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf
+-lowering-+.f32N/A
associate-*r/N/A
*-commutativeN/A
associate-/l*N/A
*-lowering-*.f32N/A
Simplified24.7%
Taylor expanded in u around 0
+-lowering-+.f32N/A
associate-*r*N/A
*-lowering-*.f32N/A
mul-1-negN/A
neg-lowering-neg.f32N/A
log1p-defineN/A
log1p-lowering-log1p.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f32N/A
*-lowering-*.f32N/A
distribute-lft-outN/A
Simplified25.0%
Final simplification25.0%
(FPCore (u s) :precision binary32 (- (* (* s 2.0) (* u (+ u 1.0))) (* s (log1p (/ PI s)))))
float code(float u, float s) {
return ((s * 2.0f) * (u * (u + 1.0f))) - (s * log1pf((((float) M_PI) / s)));
}
function code(u, s) return Float32(Float32(Float32(s * Float32(2.0)) * Float32(u * Float32(u + Float32(1.0)))) - Float32(s * log1p(Float32(Float32(pi) / s)))) end
\begin{array}{l}
\\
\left(s \cdot 2\right) \cdot \left(u \cdot \left(u + 1\right)\right) - s \cdot \mathsf{log1p}\left(\frac{\pi}{s}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf
+-lowering-+.f32N/A
associate-*r/N/A
*-commutativeN/A
associate-/l*N/A
*-lowering-*.f32N/A
Simplified24.7%
Taylor expanded in u around 0
+-lowering-+.f32N/A
associate-*r*N/A
*-lowering-*.f32N/A
mul-1-negN/A
neg-lowering-neg.f32N/A
log1p-defineN/A
log1p-lowering-log1p.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f32N/A
*-lowering-*.f32N/A
distribute-lft-outN/A
Simplified25.0%
Taylor expanded in s around 0
associate-*r*N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f3225.0%
Simplified25.0%
Final simplification25.0%
(FPCore (u s) :precision binary32 (* (- s) (log1p (/ PI s))))
float code(float u, float s) {
return -s * log1pf((((float) M_PI) / s));
}
function code(u, s) return Float32(Float32(-s) * log1p(Float32(Float32(pi) / s))) end
\begin{array}{l}
\\
\left(-s\right) \cdot \mathsf{log1p}\left(\frac{\pi}{s}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf
+-lowering-+.f32N/A
associate-*r/N/A
*-commutativeN/A
associate-/l*N/A
*-lowering-*.f32N/A
Simplified24.7%
Taylor expanded in u around 0
associate-*r*N/A
*-lowering-*.f32N/A
mul-1-negN/A
neg-lowering-neg.f32N/A
log1p-defineN/A
log1p-lowering-log1p.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f3225.0%
Simplified25.0%
(FPCore (u s) :precision binary32 (/ (- 0.0 (/ (* s s) s)) (/ s PI)))
float code(float u, float s) {
return (0.0f - ((s * s) / s)) / (s / ((float) M_PI));
}
function code(u, s) return Float32(Float32(Float32(0.0) - Float32(Float32(s * s) / s)) / Float32(s / Float32(pi))) end
function tmp = code(u, s) tmp = (single(0.0) - ((s * s) / s)) / (s / single(pi)); end
\begin{array}{l}
\\
\frac{0 - \frac{s \cdot s}{s}}{\frac{s}{\pi}}
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in u around 0
/-lowering-/.f32N/A
PI-lowering-PI.f3210.7%
Simplified10.7%
clear-numN/A
un-div-invN/A
/-lowering-/.f32N/A
neg-lowering-neg.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f3210.7%
Applied egg-rr10.7%
neg-sub0N/A
flip--N/A
/-lowering-/.f32N/A
metadata-evalN/A
--lowering--.f32N/A
*-lowering-*.f32N/A
+-lowering-+.f3213.8%
Applied egg-rr13.8%
Final simplification13.8%
(FPCore (u s) :precision binary32 (* (/ PI s) (- 0.0 (/ (* s s) s))))
float code(float u, float s) {
return (((float) M_PI) / s) * (0.0f - ((s * s) / s));
}
function code(u, s) return Float32(Float32(Float32(pi) / s) * Float32(Float32(0.0) - Float32(Float32(s * s) / s))) end
function tmp = code(u, s) tmp = (single(pi) / s) * (single(0.0) - ((s * s) / s)); end
\begin{array}{l}
\\
\frac{\pi}{s} \cdot \left(0 - \frac{s \cdot s}{s}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in u around 0
/-lowering-/.f32N/A
PI-lowering-PI.f3210.7%
Simplified10.7%
neg-sub0N/A
flip--N/A
metadata-evalN/A
neg-sub0N/A
/-lowering-/.f32N/A
distribute-rgt-neg-inN/A
*-lowering-*.f32N/A
neg-lowering-neg.f32N/A
+-lowering-+.f3213.7%
Applied egg-rr13.7%
Final simplification13.7%
(FPCore (u s) :precision binary32 (* (* PI 4.0) (+ (* u 0.5) -0.25)))
float code(float u, float s) {
return (((float) M_PI) * 4.0f) * ((u * 0.5f) + -0.25f);
}
function code(u, s) return Float32(Float32(Float32(pi) * Float32(4.0)) * Float32(Float32(u * Float32(0.5)) + Float32(-0.25))) end
function tmp = code(u, s) tmp = (single(pi) * single(4.0)) * ((u * single(0.5)) + single(-0.25)); end
\begin{array}{l}
\\
\left(\pi \cdot 4\right) \cdot \left(u \cdot 0.5 + -0.25\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf
+-lowering-+.f32N/A
associate-*r/N/A
*-commutativeN/A
associate-/l*N/A
*-lowering-*.f32N/A
Simplified24.7%
*-lowering-*.f32N/A
neg-lowering-neg.f32N/A
log1p-defineN/A
log1p-lowering-log1p.f32N/A
clear-numN/A
un-div-invN/A
/-lowering-/.f32N/A
associate-*l*N/A
distribute-lft-outN/A
*-lowering-*.f32N/A
PI-lowering-PI.f32N/A
+-lowering-+.f32N/A
*-lowering-*.f32N/A
/-lowering-/.f3224.8%
Applied egg-rr24.8%
Taylor expanded in s around inf
associate-*r*N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
PI-lowering-PI.f32N/A
sub-negN/A
metadata-evalN/A
+-lowering-+.f32N/A
*-commutativeN/A
*-lowering-*.f3210.9%
Simplified10.9%
Final simplification10.9%
(FPCore (u s) :precision binary32 (- (* PI (* u 2.0)) PI))
float code(float u, float s) {
return (((float) M_PI) * (u * 2.0f)) - ((float) M_PI);
}
function code(u, s) return Float32(Float32(Float32(pi) * Float32(u * Float32(2.0))) - Float32(pi)) end
function tmp = code(u, s) tmp = (single(pi) * (u * single(2.0))) - single(pi); end
\begin{array}{l}
\\
\pi \cdot \left(u \cdot 2\right) - \pi
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in s around inf
+-lowering-+.f32N/A
associate-*r/N/A
*-commutativeN/A
associate-/l*N/A
*-lowering-*.f32N/A
Simplified24.7%
Taylor expanded in u around 0
+-lowering-+.f32N/A
associate-*r*N/A
*-lowering-*.f32N/A
mul-1-negN/A
neg-lowering-neg.f32N/A
log1p-defineN/A
log1p-lowering-log1p.f32N/A
/-lowering-/.f32N/A
PI-lowering-PI.f32N/A
*-lowering-*.f32N/A
distribute-lft-outN/A
Simplified25.0%
Taylor expanded in s around inf
+-lowering-+.f32N/A
mul-1-negN/A
neg-lowering-neg.f32N/A
PI-lowering-PI.f32N/A
associate-*r*N/A
*-lowering-*.f32N/A
*-lowering-*.f32N/A
PI-lowering-PI.f3210.9%
Simplified10.9%
Final simplification10.9%
(FPCore (u s) :precision binary32 (* PI (* s (/ -1.0 s))))
float code(float u, float s) {
return ((float) M_PI) * (s * (-1.0f / s));
}
function code(u, s) return Float32(Float32(pi) * Float32(s * Float32(Float32(-1.0) / s))) end
function tmp = code(u, s) tmp = single(pi) * (s * (single(-1.0) / s)); end
\begin{array}{l}
\\
\pi \cdot \left(s \cdot \frac{-1}{s}\right)
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in u around 0
/-lowering-/.f32N/A
PI-lowering-PI.f3210.7%
Simplified10.7%
*-commutativeN/A
div-invN/A
associate-*l*N/A
*-lowering-*.f32N/A
PI-lowering-PI.f32N/A
*-lowering-*.f32N/A
/-lowering-/.f32N/A
neg-lowering-neg.f3210.7%
Applied egg-rr10.7%
Final simplification10.7%
(FPCore (u s) :precision binary32 (- PI))
float code(float u, float s) {
return -((float) M_PI);
}
function code(u, s) return Float32(-Float32(pi)) end
function tmp = code(u, s) tmp = -single(pi); end
\begin{array}{l}
\\
-\pi
\end{array}
Initial program 99.0%
Simplified99.0%
Taylor expanded in u around 0
mul-1-negN/A
neg-lowering-neg.f32N/A
PI-lowering-PI.f3210.7%
Simplified10.7%
herbie shell --seed 2024150
(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))))