
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(*
(* (/ 1.0 (sqrt PI)) (/ (sqrt (- (- 1.0 cosTheta) cosTheta)) cosTheta))
(exp (* (- cosTheta) cosTheta))))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + (((1.0f / sqrtf(((float) M_PI))) * (sqrtf(((1.0f - cosTheta) - cosTheta)) / cosTheta)) * expf((-cosTheta * cosTheta))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(Float32(Float32(Float32(1.0) / sqrt(Float32(pi))) * Float32(sqrt(Float32(Float32(Float32(1.0) - cosTheta) - cosTheta)) / cosTheta)) * exp(Float32(Float32(-cosTheta) * cosTheta))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / ((single(1.0) + c) + (((single(1.0) / sqrt(single(pi))) * (sqrt(((single(1.0) - cosTheta) - cosTheta)) / cosTheta)) * exp((-cosTheta * cosTheta)))); end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}}
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 12 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(*
(* (/ 1.0 (sqrt PI)) (/ (sqrt (- (- 1.0 cosTheta) cosTheta)) cosTheta))
(exp (* (- cosTheta) cosTheta))))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + (((1.0f / sqrtf(((float) M_PI))) * (sqrtf(((1.0f - cosTheta) - cosTheta)) / cosTheta)) * expf((-cosTheta * cosTheta))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(Float32(Float32(Float32(1.0) / sqrt(Float32(pi))) * Float32(sqrt(Float32(Float32(Float32(1.0) - cosTheta) - cosTheta)) / cosTheta)) * exp(Float32(Float32(-cosTheta) * cosTheta))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / ((single(1.0) + c) + (((single(1.0) / sqrt(single(pi))) * (sqrt(((single(1.0) - cosTheta) - cosTheta)) / cosTheta)) * exp((-cosTheta * cosTheta)))); end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}}
\end{array}
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
1.0
(fma
(/ (sqrt (+ 1.0 (* cosTheta -2.0))) (* cosTheta (sqrt PI)))
(pow (exp (- cosTheta)) cosTheta)
c))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + fmaf((sqrtf((1.0f + (cosTheta * -2.0f))) / (cosTheta * sqrtf(((float) M_PI)))), powf(expf(-cosTheta), cosTheta), c));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + fma(Float32(sqrt(Float32(Float32(1.0) + Float32(cosTheta * Float32(-2.0)))) / Float32(cosTheta * sqrt(Float32(pi)))), (exp(Float32(-cosTheta)) ^ cosTheta), c))) end
\begin{array}{l}
\\
\frac{1}{1 + \mathsf{fma}\left(\frac{\sqrt{1 + cosTheta \cdot -2}}{cosTheta \cdot \sqrt{\pi}}, {\left(e^{-cosTheta}\right)}^{cosTheta}, c\right)}
\end{array}
Initial program 98.0%
associate-+l+98.0%
+-commutative98.0%
fma-define98.0%
Simplified98.5%
Final simplification98.5%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(*
(/ (sqrt (- 1.0 (+ cosTheta cosTheta))) (* cosTheta (sqrt PI)))
(exp (* cosTheta (- cosTheta)))))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + ((sqrtf((1.0f - (cosTheta + cosTheta))) / (cosTheta * sqrtf(((float) M_PI)))) * expf((cosTheta * -cosTheta))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(Float32(sqrt(Float32(Float32(1.0) - Float32(cosTheta + cosTheta))) / Float32(cosTheta * sqrt(Float32(pi)))) * exp(Float32(cosTheta * Float32(-cosTheta)))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / ((single(1.0) + c) + ((sqrt((single(1.0) - (cosTheta + cosTheta))) / (cosTheta * sqrt(single(pi)))) * exp((cosTheta * -cosTheta)))); end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + \frac{\sqrt{1 - \left(cosTheta + cosTheta\right)}}{cosTheta \cdot \sqrt{\pi}} \cdot e^{cosTheta \cdot \left(-cosTheta\right)}}
\end{array}
Initial program 98.0%
frac-times98.6%
*-un-lft-identity98.6%
associate--l-98.5%
Applied egg-rr98.5%
Final simplification98.5%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
1.0
(*
(/ (exp (- (pow cosTheta 2.0))) cosTheta)
(sqrt (/ (- 1.0 (* cosTheta 2.0)) PI))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + ((expf(-powf(cosTheta, 2.0f)) / cosTheta) * sqrtf(((1.0f - (cosTheta * 2.0f)) / ((float) M_PI)))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(Float32(exp(Float32(-(cosTheta ^ Float32(2.0)))) / cosTheta) * sqrt(Float32(Float32(Float32(1.0) - Float32(cosTheta * Float32(2.0))) / Float32(pi)))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (single(1.0) + ((exp(-(cosTheta ^ single(2.0))) / cosTheta) * sqrt(((single(1.0) - (cosTheta * single(2.0))) / single(pi))))); end
\begin{array}{l}
\\
\frac{1}{1 + \frac{e^{-{cosTheta}^{2}}}{cosTheta} \cdot \sqrt{\frac{1 - cosTheta \cdot 2}{\pi}}}
\end{array}
Initial program 98.0%
associate-*l/98.5%
*-un-lft-identity98.5%
associate--l-98.5%
Applied egg-rr98.5%
Taylor expanded in c around 0 97.7%
neg-mul-197.7%
*-commutative97.7%
Simplified97.7%
Final simplification97.7%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(*
(exp (* cosTheta (- cosTheta)))
(/
(+ 1.0 (* cosTheta (+ (* cosTheta (- (* cosTheta -0.5) 0.5)) -1.0)))
(* cosTheta (sqrt PI)))))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + (expf((cosTheta * -cosTheta)) * ((1.0f + (cosTheta * ((cosTheta * ((cosTheta * -0.5f) - 0.5f)) + -1.0f))) / (cosTheta * sqrtf(((float) M_PI))))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(exp(Float32(cosTheta * Float32(-cosTheta))) * Float32(Float32(Float32(1.0) + Float32(cosTheta * Float32(Float32(cosTheta * Float32(Float32(cosTheta * Float32(-0.5)) - Float32(0.5))) + Float32(-1.0)))) / Float32(cosTheta * sqrt(Float32(pi))))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / ((single(1.0) + c) + (exp((cosTheta * -cosTheta)) * ((single(1.0) + (cosTheta * ((cosTheta * ((cosTheta * single(-0.5)) - single(0.5))) + single(-1.0)))) / (cosTheta * sqrt(single(pi)))))); end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + e^{cosTheta \cdot \left(-cosTheta\right)} \cdot \frac{1 + cosTheta \cdot \left(cosTheta \cdot \left(cosTheta \cdot -0.5 - 0.5\right) + -1\right)}{cosTheta \cdot \sqrt{\pi}}}
\end{array}
Initial program 98.0%
frac-times98.6%
*-un-lft-identity98.6%
associate--l-98.5%
Applied egg-rr98.5%
Taylor expanded in cosTheta around 0 97.6%
Final simplification97.6%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(-
(+ 1.0 c)
(*
(exp (* cosTheta (- cosTheta)))
(/
(- -1.0 (* cosTheta (+ (* cosTheta -0.5) -1.0)))
(* cosTheta (sqrt PI)))))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) - (expf((cosTheta * -cosTheta)) * ((-1.0f - (cosTheta * ((cosTheta * -0.5f) + -1.0f))) / (cosTheta * sqrtf(((float) M_PI))))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) - Float32(exp(Float32(cosTheta * Float32(-cosTheta))) * Float32(Float32(Float32(-1.0) - Float32(cosTheta * Float32(Float32(cosTheta * Float32(-0.5)) + Float32(-1.0)))) / Float32(cosTheta * sqrt(Float32(pi))))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / ((single(1.0) + c) - (exp((cosTheta * -cosTheta)) * ((single(-1.0) - (cosTheta * ((cosTheta * single(-0.5)) + single(-1.0)))) / (cosTheta * sqrt(single(pi)))))); end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) - e^{cosTheta \cdot \left(-cosTheta\right)} \cdot \frac{-1 - cosTheta \cdot \left(cosTheta \cdot -0.5 + -1\right)}{cosTheta \cdot \sqrt{\pi}}}
\end{array}
Initial program 98.0%
frac-times98.6%
*-un-lft-identity98.6%
associate--l-98.5%
Applied egg-rr98.5%
Taylor expanded in cosTheta around 0 97.1%
Final simplification97.1%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(*
(exp (* cosTheta (- cosTheta)))
(/ (- 1.0 cosTheta) (* cosTheta (sqrt PI)))))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + (expf((cosTheta * -cosTheta)) * ((1.0f - cosTheta) / (cosTheta * sqrtf(((float) M_PI))))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(exp(Float32(cosTheta * Float32(-cosTheta))) * Float32(Float32(Float32(1.0) - cosTheta) / Float32(cosTheta * sqrt(Float32(pi))))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / ((single(1.0) + c) + (exp((cosTheta * -cosTheta)) * ((single(1.0) - cosTheta) / (cosTheta * sqrt(single(pi)))))); end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + e^{cosTheta \cdot \left(-cosTheta\right)} \cdot \frac{1 - cosTheta}{cosTheta \cdot \sqrt{\pi}}}
\end{array}
Initial program 98.0%
frac-times98.6%
*-un-lft-identity98.6%
associate--l-98.5%
Applied egg-rr98.5%
Taylor expanded in cosTheta around 0 96.0%
mul-1-neg96.0%
sub-neg96.0%
Simplified96.0%
Final simplification96.0%
(FPCore (cosTheta c) :precision binary32 (* cosTheta (+ (sqrt PI) (* (* cosTheta PI) (+ -1.0 (- (sqrt (/ 1.0 PI)) c))))))
float code(float cosTheta, float c) {
return cosTheta * (sqrtf(((float) M_PI)) + ((cosTheta * ((float) M_PI)) * (-1.0f + (sqrtf((1.0f / ((float) M_PI))) - c))));
}
function code(cosTheta, c) return Float32(cosTheta * Float32(sqrt(Float32(pi)) + Float32(Float32(cosTheta * Float32(pi)) * Float32(Float32(-1.0) + Float32(sqrt(Float32(Float32(1.0) / Float32(pi))) - c))))) end
function tmp = code(cosTheta, c) tmp = cosTheta * (sqrt(single(pi)) + ((cosTheta * single(pi)) * (single(-1.0) + (sqrt((single(1.0) / single(pi))) - c)))); end
\begin{array}{l}
\\
cosTheta \cdot \left(\sqrt{\pi} + \left(cosTheta \cdot \pi\right) \cdot \left(-1 + \left(\sqrt{\frac{1}{\pi}} - c\right)\right)\right)
\end{array}
Initial program 98.0%
associate-+l+98.0%
*-commutative98.0%
exp-prod98.0%
Simplified98.0%
Taylor expanded in cosTheta around 0 95.6%
mul-1-neg95.6%
unsub-neg95.6%
associate-*r*95.6%
mul-1-neg95.6%
unsub-neg95.6%
Simplified95.6%
Final simplification95.6%
(FPCore (cosTheta c) :precision binary32 (let* ((t_0 (sqrt (/ 1.0 PI)))) (/ cosTheta (+ t_0 (* cosTheta (- 1.0 t_0))))))
float code(float cosTheta, float c) {
float t_0 = sqrtf((1.0f / ((float) M_PI)));
return cosTheta / (t_0 + (cosTheta * (1.0f - t_0)));
}
function code(cosTheta, c) t_0 = sqrt(Float32(Float32(1.0) / Float32(pi))) return Float32(cosTheta / Float32(t_0 + Float32(cosTheta * Float32(Float32(1.0) - t_0)))) end
function tmp = code(cosTheta, c) t_0 = sqrt((single(1.0) / single(pi))); tmp = cosTheta / (t_0 + (cosTheta * (single(1.0) - t_0))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{\frac{1}{\pi}}\\
\frac{cosTheta}{t\_0 + cosTheta \cdot \left(1 - t\_0\right)}
\end{array}
\end{array}
Initial program 98.0%
+-commutative98.0%
fma-define98.0%
associate-*l/98.5%
*-lft-identity98.5%
sub-neg98.5%
associate--l+98.5%
unsub-neg98.5%
neg-mul-198.5%
neg-mul-198.5%
distribute-rgt-out98.5%
metadata-eval98.5%
*-commutative98.5%
exp-prod98.5%
Simplified98.5%
Taylor expanded in cosTheta around 0 95.2%
+-commutative95.2%
mul-1-neg95.2%
Simplified95.2%
Taylor expanded in c around 0 95.1%
Final simplification95.1%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (+ 1.0 (+ c (* (sqrt (/ 1.0 PI)) (+ -1.0 (/ 1.0 cosTheta)))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (c + (sqrtf((1.0f / ((float) M_PI))) * (-1.0f + (1.0f / cosTheta)))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(c + Float32(sqrt(Float32(Float32(1.0) / Float32(pi))) * Float32(Float32(-1.0) + Float32(Float32(1.0) / cosTheta)))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (single(1.0) + (c + (sqrt((single(1.0) / single(pi))) * (single(-1.0) + (single(1.0) / cosTheta))))); end
\begin{array}{l}
\\
\frac{1}{1 + \left(c + \sqrt{\frac{1}{\pi}} \cdot \left(-1 + \frac{1}{cosTheta}\right)\right)}
\end{array}
Initial program 98.0%
+-commutative98.0%
fma-define98.0%
associate-*l/98.5%
*-lft-identity98.5%
sub-neg98.5%
associate--l+98.5%
unsub-neg98.5%
neg-mul-198.5%
neg-mul-198.5%
distribute-rgt-out98.5%
metadata-eval98.5%
*-commutative98.5%
exp-prod98.5%
Simplified98.5%
Taylor expanded in cosTheta around 0 95.2%
+-commutative95.2%
mul-1-neg95.2%
Simplified95.2%
Taylor expanded in cosTheta around inf 95.1%
sub-neg95.1%
+-commutative95.1%
associate-+r+95.1%
sub-neg95.1%
associate-+r+95.1%
+-commutative95.1%
associate-+r-95.1%
+-commutative95.1%
associate--l+95.1%
associate-+l+95.1%
Simplified95.1%
Final simplification95.1%
(FPCore (cosTheta c) :precision binary32 (* cosTheta (sqrt PI)))
float code(float cosTheta, float c) {
return cosTheta * sqrtf(((float) M_PI));
}
function code(cosTheta, c) return Float32(cosTheta * sqrt(Float32(pi))) end
function tmp = code(cosTheta, c) tmp = cosTheta * sqrt(single(pi)); end
\begin{array}{l}
\\
cosTheta \cdot \sqrt{\pi}
\end{array}
Initial program 98.0%
associate-+l+98.0%
*-commutative98.0%
exp-prod98.0%
Simplified98.0%
Taylor expanded in cosTheta around 0 92.4%
Final simplification92.4%
(FPCore (cosTheta c) :precision binary32 (- 1.0 c))
float code(float cosTheta, float c) {
return 1.0f - c;
}
real(4) function code(costheta, c)
real(4), intent (in) :: costheta
real(4), intent (in) :: c
code = 1.0e0 - c
end function
function code(cosTheta, c) return Float32(Float32(1.0) - c) end
function tmp = code(cosTheta, c) tmp = single(1.0) - c; end
\begin{array}{l}
\\
1 - c
\end{array}
Initial program 98.0%
associate-+l+98.0%
+-commutative98.0%
fma-define98.0%
Simplified98.5%
associate-/l/98.5%
clear-num98.4%
inv-pow98.4%
+-commutative98.4%
fma-define98.4%
Applied egg-rr98.4%
unpow-198.4%
Simplified98.4%
Taylor expanded in cosTheta around 0 92.0%
Taylor expanded in cosTheta around inf 11.1%
Taylor expanded in c around 0 11.1%
mul-1-neg11.1%
unsub-neg11.1%
Simplified11.1%
Final simplification11.1%
(FPCore (cosTheta c) :precision binary32 1.0)
float code(float cosTheta, float c) {
return 1.0f;
}
real(4) function code(costheta, c)
real(4), intent (in) :: costheta
real(4), intent (in) :: c
code = 1.0e0
end function
function code(cosTheta, c) return Float32(1.0) end
function tmp = code(cosTheta, c) tmp = single(1.0); end
\begin{array}{l}
\\
1
\end{array}
Initial program 98.0%
associate-+l+98.0%
+-commutative98.0%
fma-define98.0%
Simplified98.5%
associate-/l/98.5%
clear-num98.4%
inv-pow98.4%
+-commutative98.4%
fma-define98.4%
Applied egg-rr98.4%
unpow-198.4%
Simplified98.4%
Taylor expanded in cosTheta around 0 92.0%
Taylor expanded in cosTheta around inf 11.1%
Taylor expanded in c around 0 11.1%
Final simplification11.1%
herbie shell --seed 2024115
(FPCore (cosTheta c)
:name "Beckmann Sample, normalization factor"
:precision binary32
:pre (and (and (< 0.0 cosTheta) (< cosTheta 0.9999)) (and (< -1.0 c) (< c 1.0)))
(/ 1.0 (+ (+ 1.0 c) (* (* (/ 1.0 (sqrt PI)) (/ (sqrt (- (- 1.0 cosTheta) cosTheta)) cosTheta)) (exp (* (- cosTheta) cosTheta))))))