
(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 8 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 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 97.8%
frac-times98.4%
*-un-lft-identity98.4%
associate--l-98.4%
*-commutative98.4%
Applied egg-rr98.4%
Final simplification98.4%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
1.0
(+
c
(*
(/ (exp (- (pow cosTheta 2.0))) cosTheta)
(sqrt (/ (+ 1.0 (* cosTheta -2.0)) PI)))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (c + ((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(c + 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) + (c + ((exp(-(cosTheta ^ single(2.0))) / cosTheta) * sqrt(((single(1.0) + (cosTheta * single(-2.0))) / single(pi)))))); end
\begin{array}{l}
\\
\frac{1}{1 + \left(c + \frac{e^{-{cosTheta}^{2}}}{cosTheta} \cdot \sqrt{\frac{1 + cosTheta \cdot -2}{\pi}}\right)}
\end{array}
Initial program 97.8%
associate-+l+97.8%
+-commutative97.8%
*-commutative97.8%
associate-*l*97.8%
fma-define97.8%
Simplified97.8%
Taylor expanded in c around 0 97.9%
Final simplification97.9%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(/
(+
(+ (* cosTheta -1.5) (+ (* (pow cosTheta 2.0) 0.5) (/ 1.0 cosTheta)))
-1.0)
(sqrt PI)))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + ((((cosTheta * -1.5f) + ((powf(cosTheta, 2.0f) * 0.5f) + (1.0f / cosTheta))) + -1.0f) / sqrtf(((float) M_PI))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(Float32(Float32(Float32(cosTheta * Float32(-1.5)) + Float32(Float32((cosTheta ^ Float32(2.0)) * Float32(0.5)) + Float32(Float32(1.0) / cosTheta))) + Float32(-1.0)) / sqrt(Float32(pi))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / ((single(1.0) + c) + ((((cosTheta * single(-1.5)) + (((cosTheta ^ single(2.0)) * single(0.5)) + (single(1.0) / cosTheta))) + single(-1.0)) / sqrt(single(pi)))); end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + \frac{\left(cosTheta \cdot -1.5 + \left({cosTheta}^{2} \cdot 0.5 + \frac{1}{cosTheta}\right)\right) + -1}{\sqrt{\pi}}}
\end{array}
Initial program 97.8%
expm1-log1p-u90.4%
frac-times90.4%
*-un-lft-identity90.4%
associate--l-90.4%
*-commutative90.4%
Applied egg-rr90.4%
*-un-lft-identity90.4%
+-commutative90.4%
*-commutative90.4%
distribute-lft-neg-out90.4%
unpow290.4%
fma-define90.4%
Applied egg-rr98.4%
*-lft-identity98.4%
fma-undefine98.4%
Simplified98.3%
Taylor expanded in cosTheta around 0 97.7%
Final simplification97.7%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (+ (+ 1.0 c) (/ (+ (+ (* cosTheta -1.5) (/ 1.0 cosTheta)) -1.0) (sqrt PI)))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + ((((cosTheta * -1.5f) + (1.0f / cosTheta)) + -1.0f) / sqrtf(((float) M_PI))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(Float32(Float32(Float32(cosTheta * Float32(-1.5)) + Float32(Float32(1.0) / cosTheta)) + Float32(-1.0)) / sqrt(Float32(pi))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / ((single(1.0) + c) + ((((cosTheta * single(-1.5)) + (single(1.0) / cosTheta)) + single(-1.0)) / sqrt(single(pi)))); end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + \frac{\left(cosTheta \cdot -1.5 + \frac{1}{cosTheta}\right) + -1}{\sqrt{\pi}}}
\end{array}
Initial program 97.8%
expm1-log1p-u90.4%
frac-times90.4%
*-un-lft-identity90.4%
associate--l-90.4%
*-commutative90.4%
Applied egg-rr90.4%
*-un-lft-identity90.4%
+-commutative90.4%
*-commutative90.4%
distribute-lft-neg-out90.4%
unpow290.4%
fma-define90.4%
Applied egg-rr98.4%
*-lft-identity98.4%
fma-undefine98.4%
Simplified98.3%
Taylor expanded in cosTheta around 0 97.1%
Final simplification97.1%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (+ (+ 1.0 c) (/ (+ (/ 1.0 cosTheta) -1.0) (sqrt PI)))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + (((1.0f / cosTheta) + -1.0f) / sqrtf(((float) M_PI))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(Float32(Float32(Float32(1.0) / cosTheta) + Float32(-1.0)) / sqrt(Float32(pi))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / ((single(1.0) + c) + (((single(1.0) / cosTheta) + single(-1.0)) / sqrt(single(pi)))); end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + \frac{\frac{1}{cosTheta} + -1}{\sqrt{\pi}}}
\end{array}
Initial program 97.8%
expm1-log1p-u90.4%
frac-times90.4%
*-un-lft-identity90.4%
associate--l-90.4%
*-commutative90.4%
Applied egg-rr90.4%
*-un-lft-identity90.4%
+-commutative90.4%
*-commutative90.4%
distribute-lft-neg-out90.4%
unpow290.4%
fma-define90.4%
Applied egg-rr98.4%
*-lft-identity98.4%
fma-undefine98.4%
Simplified98.3%
Taylor expanded in cosTheta around 0 95.4%
Final simplification95.4%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (+ (+ 1.0 c) (/ (/ (- 1.0 cosTheta) cosTheta) (sqrt PI)))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + (((1.0f - cosTheta) / cosTheta) / sqrtf(((float) M_PI))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(Float32(Float32(Float32(1.0) - cosTheta) / cosTheta) / sqrt(Float32(pi))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / ((single(1.0) + c) + (((single(1.0) - cosTheta) / cosTheta) / sqrt(single(pi)))); end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + \frac{\frac{1 - cosTheta}{cosTheta}}{\sqrt{\pi}}}
\end{array}
Initial program 97.8%
expm1-log1p-u90.4%
frac-times90.4%
*-un-lft-identity90.4%
associate--l-90.4%
*-commutative90.4%
Applied egg-rr90.4%
*-un-lft-identity90.4%
+-commutative90.4%
*-commutative90.4%
distribute-lft-neg-out90.4%
unpow290.4%
fma-define90.4%
Applied egg-rr98.4%
*-lft-identity98.4%
fma-undefine98.4%
Simplified98.3%
Taylor expanded in cosTheta around 0 95.4%
neg-mul-195.4%
unsub-neg95.4%
Simplified95.4%
Final simplification95.4%
(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 97.8%
associate-+l+97.8%
+-commutative97.8%
fma-define97.8%
Simplified98.4%
Taylor expanded in cosTheta around 0 92.5%
Final simplification92.5%
(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 97.8%
associate-+l+97.8%
+-commutative97.8%
*-commutative97.8%
associate-*l*97.8%
fma-define97.8%
Simplified97.8%
Taylor expanded in c around inf 10.6%
Taylor expanded in c around 0 10.6%
Final simplification10.6%
herbie shell --seed 2024062
(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))))))