
(FPCore (x s) :precision binary32 (let* ((t_0 (exp (/ (- (fabs x)) s))) (t_1 (+ 1.0 t_0))) (/ t_0 (* (* s t_1) t_1))))
float code(float x, float s) {
float t_0 = expf((-fabsf(x) / s));
float t_1 = 1.0f + t_0;
return t_0 / ((s * t_1) * t_1);
}
real(4) function code(x, s)
real(4), intent (in) :: x
real(4), intent (in) :: s
real(4) :: t_0
real(4) :: t_1
t_0 = exp((-abs(x) / s))
t_1 = 1.0e0 + t_0
code = t_0 / ((s * t_1) * t_1)
end function
function code(x, s) t_0 = exp(Float32(Float32(-abs(x)) / s)) t_1 = Float32(Float32(1.0) + t_0) return Float32(t_0 / Float32(Float32(s * t_1) * t_1)) end
function tmp = code(x, s) t_0 = exp((-abs(x) / s)); t_1 = single(1.0) + t_0; tmp = t_0 / ((s * t_1) * t_1); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := e^{\frac{-\left|x\right|}{s}}\\
t_1 := 1 + t\_0\\
\frac{t\_0}{\left(s \cdot t\_1\right) \cdot t\_1}
\end{array}
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 11 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x s) :precision binary32 (let* ((t_0 (exp (/ (- (fabs x)) s))) (t_1 (+ 1.0 t_0))) (/ t_0 (* (* s t_1) t_1))))
float code(float x, float s) {
float t_0 = expf((-fabsf(x) / s));
float t_1 = 1.0f + t_0;
return t_0 / ((s * t_1) * t_1);
}
real(4) function code(x, s)
real(4), intent (in) :: x
real(4), intent (in) :: s
real(4) :: t_0
real(4) :: t_1
t_0 = exp((-abs(x) / s))
t_1 = 1.0e0 + t_0
code = t_0 / ((s * t_1) * t_1)
end function
function code(x, s) t_0 = exp(Float32(Float32(-abs(x)) / s)) t_1 = Float32(Float32(1.0) + t_0) return Float32(t_0 / Float32(Float32(s * t_1) * t_1)) end
function tmp = code(x, s) t_0 = exp((-abs(x) / s)); t_1 = single(1.0) + t_0; tmp = t_0 / ((s * t_1) * t_1); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := e^{\frac{-\left|x\right|}{s}}\\
t_1 := 1 + t\_0\\
\frac{t\_0}{\left(s \cdot t\_1\right) \cdot t\_1}
\end{array}
\end{array}
x_m = (fabs.f32 x) (FPCore (x_m s) :precision binary32 (if (<= (fabs x_m) 1.0) (/ (exp (+ (/ x_m s) (* -2.0 (log1p (exp (/ x_m s)))))) s) (exp (/ x_m (- s)))))
x_m = fabs(x);
float code(float x_m, float s) {
float tmp;
if (fabsf(x_m) <= 1.0f) {
tmp = expf(((x_m / s) + (-2.0f * log1pf(expf((x_m / s)))))) / s;
} else {
tmp = expf((x_m / -s));
}
return tmp;
}
x_m = abs(x) function code(x_m, s) tmp = Float32(0.0) if (abs(x_m) <= Float32(1.0)) tmp = Float32(exp(Float32(Float32(x_m / s) + Float32(Float32(-2.0) * log1p(exp(Float32(x_m / s)))))) / s); else tmp = exp(Float32(x_m / Float32(-s))); end return tmp end
\begin{array}{l}
x_m = \left|x\right|
\\
\begin{array}{l}
\mathbf{if}\;\left|x\_m\right| \leq 1:\\
\;\;\;\;\frac{e^{\frac{x\_m}{s} + -2 \cdot \mathsf{log1p}\left(e^{\frac{x\_m}{s}}\right)}}{s}\\
\mathbf{else}:\\
\;\;\;\;e^{\frac{x\_m}{-s}}\\
\end{array}
\end{array}
if (fabs.f32 x) < 1Initial program 99.5%
fabs-neg99.5%
distribute-frac-neg99.5%
distribute-frac-neg299.5%
fabs-neg99.5%
*-commutative99.5%
fabs-neg99.5%
+-commutative99.5%
fabs-neg99.5%
Simplified99.5%
Applied egg-rr76.6%
*-lft-identity76.6%
*-commutative76.6%
exp-to-pow76.5%
log1p-undefine76.7%
*-commutative76.7%
rem-exp-log72.2%
exp-sum71.9%
exp-diff94.6%
associate--r+94.7%
exp-diff95.1%
cancel-sign-sub-inv95.1%
metadata-eval95.1%
Simplified99.6%
if 1 < (fabs.f32 x) Initial program 100.0%
fabs-neg100.0%
distribute-frac-neg100.0%
distribute-frac-neg2100.0%
fabs-neg100.0%
*-commutative100.0%
fabs-neg100.0%
+-commutative100.0%
fabs-neg100.0%
Simplified100.0%
Taylor expanded in s around inf 100.0%
clear-num100.0%
inv-pow100.0%
Applied egg-rr56.1%
unpow-156.1%
associate-*l*56.1%
Simplified56.1%
add-exp-log56.1%
log-rec56.1%
associate-*r*56.1%
log-prod56.1%
add-log-exp56.1%
Applied egg-rr56.1%
Taylor expanded in s around 0 56.1%
Final simplification81.3%
x_m = (fabs.f32 x) (FPCore (x_m s) :precision binary32 (let* ((t_0 (exp (/ (- (fabs x_m)) s)))) (/ t_0 (* (+ t_0 1.0) (+ s (/ s (exp (/ (fabs x_m) s))))))))
x_m = fabs(x);
float code(float x_m, float s) {
float t_0 = expf((-fabsf(x_m) / s));
return t_0 / ((t_0 + 1.0f) * (s + (s / expf((fabsf(x_m) / s)))));
}
x_m = abs(x)
real(4) function code(x_m, s)
real(4), intent (in) :: x_m
real(4), intent (in) :: s
real(4) :: t_0
t_0 = exp((-abs(x_m) / s))
code = t_0 / ((t_0 + 1.0e0) * (s + (s / exp((abs(x_m) / s)))))
end function
x_m = abs(x) function code(x_m, s) t_0 = exp(Float32(Float32(-abs(x_m)) / s)) return Float32(t_0 / Float32(Float32(t_0 + Float32(1.0)) * Float32(s + Float32(s / exp(Float32(abs(x_m) / s)))))) end
x_m = abs(x); function tmp = code(x_m, s) t_0 = exp((-abs(x_m) / s)); tmp = t_0 / ((t_0 + single(1.0)) * (s + (s / exp((abs(x_m) / s))))); end
\begin{array}{l}
x_m = \left|x\right|
\\
\begin{array}{l}
t_0 := e^{\frac{-\left|x\_m\right|}{s}}\\
\frac{t\_0}{\left(t\_0 + 1\right) \cdot \left(s + \frac{s}{e^{\frac{\left|x\_m\right|}{s}}}\right)}
\end{array}
\end{array}
Initial program 99.7%
Simplified99.8%
Final simplification99.8%
x_m = (fabs.f32 x) (FPCore (x_m s) :precision binary32 (if (<= x_m 7.199999771511762e-21) (/ 0.25 s) (exp (/ x_m (- s)))))
x_m = fabs(x);
float code(float x_m, float s) {
float tmp;
if (x_m <= 7.199999771511762e-21f) {
tmp = 0.25f / s;
} else {
tmp = expf((x_m / -s));
}
return tmp;
}
x_m = abs(x)
real(4) function code(x_m, s)
real(4), intent (in) :: x_m
real(4), intent (in) :: s
real(4) :: tmp
if (x_m <= 7.199999771511762e-21) then
tmp = 0.25e0 / s
else
tmp = exp((x_m / -s))
end if
code = tmp
end function
x_m = abs(x) function code(x_m, s) tmp = Float32(0.0) if (x_m <= Float32(7.199999771511762e-21)) tmp = Float32(Float32(0.25) / s); else tmp = exp(Float32(x_m / Float32(-s))); end return tmp end
x_m = abs(x); function tmp_2 = code(x_m, s) tmp = single(0.0); if (x_m <= single(7.199999771511762e-21)) tmp = single(0.25) / s; else tmp = exp((x_m / -s)); end tmp_2 = tmp; end
\begin{array}{l}
x_m = \left|x\right|
\\
\begin{array}{l}
\mathbf{if}\;x\_m \leq 7.199999771511762 \cdot 10^{-21}:\\
\;\;\;\;\frac{0.25}{s}\\
\mathbf{else}:\\
\;\;\;\;e^{\frac{x\_m}{-s}}\\
\end{array}
\end{array}
if x < 7.1999998e-21Initial program 99.6%
fabs-neg99.6%
distribute-frac-neg99.6%
distribute-frac-neg299.6%
fabs-neg99.6%
*-commutative99.6%
fabs-neg99.6%
+-commutative99.6%
fabs-neg99.6%
Simplified99.7%
Taylor expanded in s around inf 42.8%
if 7.1999998e-21 < x Initial program 99.8%
fabs-neg99.8%
distribute-frac-neg99.8%
distribute-frac-neg299.8%
fabs-neg99.8%
*-commutative99.8%
fabs-neg99.8%
+-commutative99.8%
fabs-neg99.8%
Simplified99.8%
Taylor expanded in s around inf 93.5%
clear-num93.5%
inv-pow93.5%
Applied egg-rr93.5%
unpow-193.5%
associate-*l*93.5%
Simplified93.5%
add-exp-log93.3%
log-rec93.3%
associate-*r*93.3%
log-prod93.3%
add-log-exp93.3%
Applied egg-rr93.3%
Taylor expanded in s around 0 87.9%
Final simplification59.9%
x_m = (fabs.f32 x) (FPCore (x_m s) :precision binary32 (/ (/ 0.5 s) (+ 1.0 (exp (/ x_m s)))))
x_m = fabs(x);
float code(float x_m, float s) {
return (0.5f / s) / (1.0f + expf((x_m / s)));
}
x_m = abs(x)
real(4) function code(x_m, s)
real(4), intent (in) :: x_m
real(4), intent (in) :: s
code = (0.5e0 / s) / (1.0e0 + exp((x_m / s)))
end function
x_m = abs(x) function code(x_m, s) return Float32(Float32(Float32(0.5) / s) / Float32(Float32(1.0) + exp(Float32(x_m / s)))) end
x_m = abs(x); function tmp = code(x_m, s) tmp = (single(0.5) / s) / (single(1.0) + exp((x_m / s))); end
\begin{array}{l}
x_m = \left|x\right|
\\
\frac{\frac{0.5}{s}}{1 + e^{\frac{x\_m}{s}}}
\end{array}
Initial program 99.7%
fabs-neg99.7%
distribute-frac-neg99.7%
distribute-frac-neg299.7%
fabs-neg99.7%
*-commutative99.7%
fabs-neg99.7%
+-commutative99.7%
fabs-neg99.7%
Simplified99.7%
Applied egg-rr63.8%
associate-*l/63.9%
*-lft-identity63.9%
Simplified63.9%
Taylor expanded in x around 0 64.5%
Final simplification64.5%
x_m = (fabs.f32 x) (FPCore (x_m s) :precision binary32 (/ 0.25 (* s (exp (/ x_m s)))))
x_m = fabs(x);
float code(float x_m, float s) {
return 0.25f / (s * expf((x_m / s)));
}
x_m = abs(x)
real(4) function code(x_m, s)
real(4), intent (in) :: x_m
real(4), intent (in) :: s
code = 0.25e0 / (s * exp((x_m / s)))
end function
x_m = abs(x) function code(x_m, s) return Float32(Float32(0.25) / Float32(s * exp(Float32(x_m / s)))) end
x_m = abs(x); function tmp = code(x_m, s) tmp = single(0.25) / (s * exp((x_m / s))); end
\begin{array}{l}
x_m = \left|x\right|
\\
\frac{0.25}{s \cdot e^{\frac{x\_m}{s}}}
\end{array}
Initial program 99.7%
fabs-neg99.7%
distribute-frac-neg99.7%
distribute-frac-neg299.7%
fabs-neg99.7%
*-commutative99.7%
fabs-neg99.7%
+-commutative99.7%
fabs-neg99.7%
Simplified99.7%
Taylor expanded in s around inf 93.7%
clear-num93.7%
inv-pow93.7%
Applied egg-rr63.7%
unpow-163.7%
associate-*l*63.7%
Simplified63.7%
Taylor expanded in s around 0 63.7%
Final simplification63.7%
x_m = (fabs.f32 x) (FPCore (x_m s) :precision binary32 (/ 0.25 (+ s (* x_m (+ 1.0 (* (/ x_m s) 0.5))))))
x_m = fabs(x);
float code(float x_m, float s) {
return 0.25f / (s + (x_m * (1.0f + ((x_m / s) * 0.5f))));
}
x_m = abs(x)
real(4) function code(x_m, s)
real(4), intent (in) :: x_m
real(4), intent (in) :: s
code = 0.25e0 / (s + (x_m * (1.0e0 + ((x_m / s) * 0.5e0))))
end function
x_m = abs(x) function code(x_m, s) return Float32(Float32(0.25) / Float32(s + Float32(x_m * Float32(Float32(1.0) + Float32(Float32(x_m / s) * Float32(0.5)))))) end
x_m = abs(x); function tmp = code(x_m, s) tmp = single(0.25) / (s + (x_m * (single(1.0) + ((x_m / s) * single(0.5))))); end
\begin{array}{l}
x_m = \left|x\right|
\\
\frac{0.25}{s + x\_m \cdot \left(1 + \frac{x\_m}{s} \cdot 0.5\right)}
\end{array}
Initial program 99.7%
fabs-neg99.7%
distribute-frac-neg99.7%
distribute-frac-neg299.7%
fabs-neg99.7%
*-commutative99.7%
fabs-neg99.7%
+-commutative99.7%
fabs-neg99.7%
Simplified99.7%
Taylor expanded in s around inf 93.7%
clear-num93.7%
inv-pow93.7%
Applied egg-rr63.7%
unpow-163.7%
associate-*l*63.7%
Simplified63.7%
Taylor expanded in s around 0 63.7%
Taylor expanded in x around 0 61.3%
*-commutative61.3%
Simplified61.3%
Final simplification61.3%
x_m = (fabs.f32 x) (FPCore (x_m s) :precision binary32 (/ 1.0 (* s (+ 4.0 (* (/ x_m s) 4.0)))))
x_m = fabs(x);
float code(float x_m, float s) {
return 1.0f / (s * (4.0f + ((x_m / s) * 4.0f)));
}
x_m = abs(x)
real(4) function code(x_m, s)
real(4), intent (in) :: x_m
real(4), intent (in) :: s
code = 1.0e0 / (s * (4.0e0 + ((x_m / s) * 4.0e0)))
end function
x_m = abs(x) function code(x_m, s) return Float32(Float32(1.0) / Float32(s * Float32(Float32(4.0) + Float32(Float32(x_m / s) * Float32(4.0))))) end
x_m = abs(x); function tmp = code(x_m, s) tmp = single(1.0) / (s * (single(4.0) + ((x_m / s) * single(4.0)))); end
\begin{array}{l}
x_m = \left|x\right|
\\
\frac{1}{s \cdot \left(4 + \frac{x\_m}{s} \cdot 4\right)}
\end{array}
Initial program 99.7%
fabs-neg99.7%
distribute-frac-neg99.7%
distribute-frac-neg299.7%
fabs-neg99.7%
*-commutative99.7%
fabs-neg99.7%
+-commutative99.7%
fabs-neg99.7%
Simplified99.7%
Taylor expanded in s around inf 93.7%
clear-num93.7%
inv-pow93.7%
Applied egg-rr63.7%
unpow-163.7%
associate-*l*63.7%
Simplified63.7%
Taylor expanded in s around inf 51.8%
Final simplification51.8%
x_m = (fabs.f32 x) (FPCore (x_m s) :precision binary32 (/ 0.25 (* s (+ 1.0 (/ x_m s)))))
x_m = fabs(x);
float code(float x_m, float s) {
return 0.25f / (s * (1.0f + (x_m / s)));
}
x_m = abs(x)
real(4) function code(x_m, s)
real(4), intent (in) :: x_m
real(4), intent (in) :: s
code = 0.25e0 / (s * (1.0e0 + (x_m / s)))
end function
x_m = abs(x) function code(x_m, s) return Float32(Float32(0.25) / Float32(s * Float32(Float32(1.0) + Float32(x_m / s)))) end
x_m = abs(x); function tmp = code(x_m, s) tmp = single(0.25) / (s * (single(1.0) + (x_m / s))); end
\begin{array}{l}
x_m = \left|x\right|
\\
\frac{0.25}{s \cdot \left(1 + \frac{x\_m}{s}\right)}
\end{array}
Initial program 99.7%
fabs-neg99.7%
distribute-frac-neg99.7%
distribute-frac-neg299.7%
fabs-neg99.7%
*-commutative99.7%
fabs-neg99.7%
+-commutative99.7%
fabs-neg99.7%
Simplified99.7%
Taylor expanded in s around inf 93.7%
clear-num93.7%
inv-pow93.7%
Applied egg-rr63.7%
unpow-163.7%
associate-*l*63.7%
Simplified63.7%
Taylor expanded in s around 0 63.7%
Taylor expanded in s around inf 51.1%
Final simplification51.1%
x_m = (fabs.f32 x) (FPCore (x_m s) :precision binary32 (/ 0.25 (+ x_m s)))
x_m = fabs(x);
float code(float x_m, float s) {
return 0.25f / (x_m + s);
}
x_m = abs(x)
real(4) function code(x_m, s)
real(4), intent (in) :: x_m
real(4), intent (in) :: s
code = 0.25e0 / (x_m + s)
end function
x_m = abs(x) function code(x_m, s) return Float32(Float32(0.25) / Float32(x_m + s)) end
x_m = abs(x); function tmp = code(x_m, s) tmp = single(0.25) / (x_m + s); end
\begin{array}{l}
x_m = \left|x\right|
\\
\frac{0.25}{x\_m + s}
\end{array}
Initial program 99.7%
fabs-neg99.7%
distribute-frac-neg99.7%
distribute-frac-neg299.7%
fabs-neg99.7%
*-commutative99.7%
fabs-neg99.7%
+-commutative99.7%
fabs-neg99.7%
Simplified99.7%
Taylor expanded in s around inf 93.7%
clear-num93.7%
inv-pow93.7%
Applied egg-rr63.7%
unpow-163.7%
associate-*l*63.7%
Simplified63.7%
Taylor expanded in s around 0 63.7%
Taylor expanded in x around 0 32.7%
Final simplification32.7%
x_m = (fabs.f32 x) (FPCore (x_m s) :precision binary32 (/ 0.25 s))
x_m = fabs(x);
float code(float x_m, float s) {
return 0.25f / s;
}
x_m = abs(x)
real(4) function code(x_m, s)
real(4), intent (in) :: x_m
real(4), intent (in) :: s
code = 0.25e0 / s
end function
x_m = abs(x) function code(x_m, s) return Float32(Float32(0.25) / s) end
x_m = abs(x); function tmp = code(x_m, s) tmp = single(0.25) / s; end
\begin{array}{l}
x_m = \left|x\right|
\\
\frac{0.25}{s}
\end{array}
Initial program 99.7%
fabs-neg99.7%
distribute-frac-neg99.7%
distribute-frac-neg299.7%
fabs-neg99.7%
*-commutative99.7%
fabs-neg99.7%
+-commutative99.7%
fabs-neg99.7%
Simplified99.7%
Taylor expanded in s around inf 31.6%
Final simplification31.6%
x_m = (fabs.f32 x) (FPCore (x_m s) :precision binary32 1.0)
x_m = fabs(x);
float code(float x_m, float s) {
return 1.0f;
}
x_m = abs(x)
real(4) function code(x_m, s)
real(4), intent (in) :: x_m
real(4), intent (in) :: s
code = 1.0e0
end function
x_m = abs(x) function code(x_m, s) return Float32(1.0) end
x_m = abs(x); function tmp = code(x_m, s) tmp = single(1.0); end
\begin{array}{l}
x_m = \left|x\right|
\\
1
\end{array}
Initial program 99.7%
fabs-neg99.7%
distribute-frac-neg99.7%
distribute-frac-neg299.7%
fabs-neg99.7%
*-commutative99.7%
fabs-neg99.7%
+-commutative99.7%
fabs-neg99.7%
Simplified99.7%
Taylor expanded in s around inf 93.7%
clear-num93.7%
inv-pow93.7%
Applied egg-rr63.7%
unpow-163.7%
associate-*l*63.7%
Simplified63.7%
add-exp-log62.1%
log-rec62.1%
associate-*r*62.1%
log-prod62.1%
add-log-exp62.1%
Applied egg-rr62.1%
neg-sub062.1%
metadata-eval62.1%
add-log-exp62.1%
sum-log62.1%
expm1-log1p-u62.1%
log-div62.1%
add-exp-log63.7%
add-sqr-sqrt63.3%
associate-/r*63.3%
Applied egg-rr4.3%
*-inverses8.5%
Simplified8.5%
Final simplification8.5%
herbie shell --seed 2024077
(FPCore (x s)
:name "Logistic distribution"
:precision binary32
:pre (and (<= 0.0 s) (<= s 1.0651631))
(/ (exp (/ (- (fabs x)) s)) (* (* s (+ 1.0 (exp (/ (- (fabs x)) s)))) (+ 1.0 (exp (/ (- (fabs x)) s))))))