
(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 9 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)
(*
(/ 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(1.0) / Float32(sqrt(Float32(pi)) / Float32(sqrt(Float32(Float32(1.0) - Float32(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) + \frac{1}{\frac{\sqrt{\pi}}{\frac{\sqrt{1 - \left(cosTheta + cosTheta\right)}}{cosTheta}}} \cdot e^{-cosTheta \cdot cosTheta}}
\end{array}
Initial program 98.2%
frac-times98.7%
*-un-lft-identity98.7%
associate--r+98.6%
associate-/l/98.5%
clear-num98.6%
Applied egg-rr98.6%
Final simplification98.6%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(*
(exp (- (* cosTheta cosTheta)))
(/ (sqrt (- 1.0 (+ cosTheta cosTheta))) (* (sqrt PI) cosTheta))))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + (expf(-(cosTheta * cosTheta)) * (sqrtf((1.0f - (cosTheta + cosTheta))) / (sqrtf(((float) M_PI)) * cosTheta))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(exp(Float32(-Float32(cosTheta * cosTheta))) * Float32(sqrt(Float32(Float32(1.0) - Float32(cosTheta + cosTheta))) / Float32(sqrt(Float32(pi)) * cosTheta))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / ((single(1.0) + c) + (exp(-(cosTheta * cosTheta)) * (sqrt((single(1.0) - (cosTheta + cosTheta))) / (sqrt(single(pi)) * cosTheta)))); end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + e^{-cosTheta \cdot cosTheta} \cdot \frac{\sqrt{1 - \left(cosTheta + cosTheta\right)}}{\sqrt{\pi} \cdot cosTheta}}
\end{array}
Initial program 98.2%
frac-times98.7%
*-un-lft-identity98.7%
associate--r+98.6%
*-commutative98.6%
Applied egg-rr98.6%
Final simplification98.6%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
1.0
(*
(sqrt (/ (+ 1.0 (* cosTheta -2.0)) PI))
(/ (exp (- (* cosTheta cosTheta))) cosTheta)))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (sqrtf(((1.0f + (cosTheta * -2.0f)) / ((float) M_PI))) * (expf(-(cosTheta * cosTheta)) / cosTheta)));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(sqrt(Float32(Float32(Float32(1.0) + Float32(cosTheta * Float32(-2.0))) / Float32(pi))) * Float32(exp(Float32(-Float32(cosTheta * cosTheta))) / cosTheta)))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (single(1.0) + (sqrt(((single(1.0) + (cosTheta * single(-2.0))) / single(pi))) * (exp(-(cosTheta * cosTheta)) / cosTheta))); end
\begin{array}{l}
\\
\frac{1}{1 + \sqrt{\frac{1 + cosTheta \cdot -2}{\pi}} \cdot \frac{e^{-cosTheta \cdot cosTheta}}{cosTheta}}
\end{array}
Initial program 98.2%
Taylor expanded in c around 0 98.2%
associate-*l/98.0%
mul-1-neg98.0%
unpow298.0%
distribute-lft-neg-out98.0%
*-commutative98.0%
cancel-sign-sub-inv98.0%
metadata-eval98.0%
Applied egg-rr98.0%
distribute-rgt-neg-out98.0%
unpow298.0%
mul-1-neg98.0%
metadata-eval98.0%
cancel-sign-sub-inv98.0%
associate-*l/98.2%
*-commutative98.2%
cancel-sign-sub-inv98.2%
metadata-eval98.2%
*-commutative98.2%
mul-1-neg98.2%
unpow298.2%
Simplified98.2%
Final simplification98.2%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (+ 1.0 (+ c (/ (+ (/ 1.0 cosTheta) (fma cosTheta -1.5 -1.0)) (sqrt PI))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (c + (((1.0f / cosTheta) + fmaf(cosTheta, -1.5f, -1.0f)) / sqrtf(((float) M_PI)))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(c + Float32(Float32(Float32(Float32(1.0) / cosTheta) + fma(cosTheta, Float32(-1.5), Float32(-1.0))) / sqrt(Float32(pi)))))) end
\begin{array}{l}
\\
\frac{1}{1 + \left(c + \frac{\frac{1}{cosTheta} + \mathsf{fma}\left(cosTheta, -1.5, -1\right)}{\sqrt{\pi}}\right)}
\end{array}
Initial program 98.2%
associate-+l+98.2%
associate-*l*98.2%
associate-*l/98.6%
*-lft-identity98.6%
Simplified98.5%
Taylor expanded in cosTheta around 0 96.7%
+-commutative96.7%
associate--l+96.7%
*-commutative96.7%
fma-neg96.7%
metadata-eval96.7%
Simplified96.7%
Final simplification96.7%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (+ 1.0 (* (+ -1.0 (+ (/ 1.0 cosTheta) (* cosTheta -1.5))) (sqrt (/ 1.0 PI))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + ((-1.0f + ((1.0f / cosTheta) + (cosTheta * -1.5f))) * sqrtf((1.0f / ((float) M_PI)))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(Float32(Float32(-1.0) + Float32(Float32(Float32(1.0) / cosTheta) + Float32(cosTheta * Float32(-1.5)))) * sqrt(Float32(Float32(1.0) / Float32(pi)))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (single(1.0) + ((single(-1.0) + ((single(1.0) / cosTheta) + (cosTheta * single(-1.5)))) * sqrt((single(1.0) / single(pi))))); end
\begin{array}{l}
\\
\frac{1}{1 + \left(-1 + \left(\frac{1}{cosTheta} + cosTheta \cdot -1.5\right)\right) \cdot \sqrt{\frac{1}{\pi}}}
\end{array}
Initial program 98.2%
associate-+l+98.2%
associate-*l*98.2%
associate-*l/98.6%
*-lft-identity98.6%
Simplified98.5%
Taylor expanded in cosTheta around 0 96.7%
+-commutative96.7%
associate--l+96.7%
*-commutative96.7%
fma-neg96.7%
metadata-eval96.7%
Simplified96.7%
Taylor expanded in c around 0 96.2%
Final simplification96.2%
(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(1.0) + Float32(c + Float32(Float32(Float32(cosTheta * Float32(-1.5)) + 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 + (((cosTheta * single(-1.5)) + ((single(1.0) / cosTheta) + single(-1.0))) / sqrt(single(pi))))); end
\begin{array}{l}
\\
\frac{1}{1 + \left(c + \frac{cosTheta \cdot -1.5 + \left(\frac{1}{cosTheta} + -1\right)}{\sqrt{\pi}}\right)}
\end{array}
Initial program 98.2%
associate-+l+98.2%
associate-*l*98.2%
associate-*l/98.6%
*-lft-identity98.6%
Simplified98.5%
Taylor expanded in cosTheta around 0 96.7%
associate--l+96.7%
*-commutative96.7%
Applied egg-rr96.7%
Final simplification96.7%
(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(1.0) + Float32(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}{1 + \left(c + \frac{\frac{1}{cosTheta} + -1}{\sqrt{\pi}}\right)}
\end{array}
Initial program 98.2%
associate-+l+98.2%
associate-*l*98.2%
associate-*l/98.6%
*-lft-identity98.6%
Simplified98.5%
Taylor expanded in cosTheta around 0 95.0%
Final simplification95.0%
(FPCore (cosTheta c) :precision binary32 (* (sqrt PI) cosTheta))
float code(float cosTheta, float c) {
return sqrtf(((float) M_PI)) * cosTheta;
}
function code(cosTheta, c) return Float32(sqrt(Float32(pi)) * cosTheta) end
function tmp = code(cosTheta, c) tmp = sqrt(single(pi)) * cosTheta; end
\begin{array}{l}
\\
\sqrt{\pi} \cdot cosTheta
\end{array}
Initial program 98.2%
associate-*r/98.0%
distribute-lft-neg-out98.0%
exp-neg98.1%
times-frac98.0%
*-commutative98.0%
times-frac98.1%
associate-*l/98.1%
Simplified98.6%
Taylor expanded in cosTheta around 0 92.0%
Final simplification92.0%
(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 98.2%
Taylor expanded in c around 0 98.2%
Taylor expanded in cosTheta around inf 11.2%
Final simplification11.2%
herbie shell --seed 2023200
(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))))))