
(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
(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%
times-frac98.5%
*-lft-identity98.5%
associate--l-98.5%
sub-neg98.5%
neg-mul-198.5%
distribute-lft-out98.5%
distribute-rgt-out98.5%
metadata-eval98.5%
exp-prod98.5%
Simplified98.5%
Final simplification98.5%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(*
(/
(*
(/ (pow PI -0.16666666666666666) (cbrt PI))
(sqrt (- 1.0 (+ cosTheta cosTheta))))
cosTheta)
(exp (* cosTheta (- cosTheta)))))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + ((((powf(((float) M_PI), -0.16666666666666666f) / cbrtf(((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((Float32(pi) ^ Float32(-0.16666666666666666)) / cbrt(Float32(pi))) * sqrt(Float32(Float32(1.0) - Float32(cosTheta + cosTheta)))) / cosTheta) * exp(Float32(cosTheta * Float32(-cosTheta)))))) end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + \frac{\frac{{\pi}^{-0.16666666666666666}}{\sqrt[3]{\pi}} \cdot \sqrt{1 - \left(cosTheta + cosTheta\right)}}{cosTheta} \cdot e^{cosTheta \cdot \left(-cosTheta\right)}}
\end{array}
Initial program 98.0%
add-cube-cbrt98.0%
cbrt-unprod98.0%
frac-times98.2%
metadata-eval98.2%
add-sqr-sqrt98.2%
inv-pow98.2%
sqrt-pow298.2%
metadata-eval98.2%
Applied egg-rr98.2%
associate-*r/98.2%
cbrt-unprod97.9%
inv-pow97.9%
metadata-eval97.9%
pow-prod-up97.9%
add-cbrt-cube97.9%
associate--l-97.8%
Applied egg-rr97.8%
add-cbrt-cube97.8%
pow-prod-up97.8%
metadata-eval97.8%
inv-pow97.8%
cbrt-unprod98.3%
*-commutative98.3%
pow1/398.3%
pow-pow98.3%
metadata-eval98.3%
cbrt-div98.3%
metadata-eval98.3%
Applied egg-rr98.3%
associate-*r/98.3%
*-rgt-identity98.3%
Simplified98.3%
Final simplification98.3%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(*
(exp (* cosTheta (- cosTheta)))
(* (pow PI -0.5) (/ (sqrt (- (- 1.0 cosTheta) cosTheta)) cosTheta))))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + (expf((cosTheta * -cosTheta)) * (powf(((float) M_PI), -0.5f) * (sqrtf(((1.0f - cosTheta) - cosTheta)) / cosTheta))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(exp(Float32(cosTheta * Float32(-cosTheta))) * Float32((Float32(pi) ^ Float32(-0.5)) * Float32(sqrt(Float32(Float32(Float32(1.0) - cosTheta) - cosTheta)) / cosTheta))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / ((single(1.0) + c) + (exp((cosTheta * -cosTheta)) * ((single(pi) ^ single(-0.5)) * (sqrt(((single(1.0) - cosTheta) - cosTheta)) / cosTheta)))); end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + e^{cosTheta \cdot \left(-cosTheta\right)} \cdot \left({\pi}^{-0.5} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right)}
\end{array}
Initial program 98.0%
*-un-lft-identity98.0%
inv-pow98.0%
sqrt-pow298.0%
metadata-eval98.0%
Applied egg-rr98.0%
*-lft-identity98.0%
Simplified98.0%
Final simplification98.0%
(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%
add-cube-cbrt98.0%
cbrt-unprod98.0%
frac-times98.2%
metadata-eval98.2%
add-sqr-sqrt98.2%
inv-pow98.2%
sqrt-pow298.2%
metadata-eval98.2%
Applied egg-rr98.2%
Taylor expanded in c around 0 98.0%
neg-mul-198.0%
cancel-sign-sub-inv98.0%
metadata-eval98.0%
*-commutative98.0%
Simplified98.0%
Final simplification98.0%
(FPCore (cosTheta c) :precision binary32 (* cosTheta (+ (sqrt PI) (* PI (* cosTheta (+ -1.0 (- (sqrt (/ 1.0 PI)) c)))))))
float code(float cosTheta, float c) {
return cosTheta * (sqrtf(((float) M_PI)) + (((float) M_PI) * (cosTheta * (-1.0f + (sqrtf((1.0f / ((float) M_PI))) - c)))));
}
function code(cosTheta, c) return Float32(cosTheta * Float32(sqrt(Float32(pi)) + Float32(Float32(pi) * Float32(cosTheta * Float32(Float32(-1.0) + Float32(sqrt(Float32(Float32(1.0) / Float32(pi))) - c)))))) end
function tmp = code(cosTheta, c) tmp = cosTheta * (sqrt(single(pi)) + (single(pi) * (cosTheta * (single(-1.0) + (sqrt((single(1.0) / single(pi))) - c))))); end
\begin{array}{l}
\\
cosTheta \cdot \left(\sqrt{\pi} + \pi \cdot \left(cosTheta \cdot \left(-1 + \left(\sqrt{\frac{1}{\pi}} - c\right)\right)\right)\right)
\end{array}
Initial program 98.0%
associate-+l+98.0%
+-commutative98.0%
fma-define98.0%
times-frac98.5%
*-lft-identity98.5%
associate--l-98.5%
sub-neg98.5%
neg-mul-198.5%
distribute-lft-out98.5%
distribute-rgt-out98.5%
metadata-eval98.5%
exp-prod98.5%
Simplified98.5%
Taylor expanded in cosTheta around 0 96.4%
mul-1-neg96.4%
unsub-neg96.4%
*-commutative96.4%
associate-*l*96.4%
mul-1-neg96.4%
unsub-neg96.4%
Simplified96.4%
Final simplification96.4%
(FPCore (cosTheta c) :precision binary32 (* cosTheta (+ (sqrt PI) (* (* cosTheta PI) (+ (sqrt (/ 1.0 PI)) -1.0)))))
float code(float cosTheta, float c) {
return cosTheta * (sqrtf(((float) M_PI)) + ((cosTheta * ((float) M_PI)) * (sqrtf((1.0f / ((float) M_PI))) + -1.0f)));
}
function code(cosTheta, c) return Float32(cosTheta * Float32(sqrt(Float32(pi)) + Float32(Float32(cosTheta * Float32(pi)) * Float32(sqrt(Float32(Float32(1.0) / Float32(pi))) + Float32(-1.0))))) end
function tmp = code(cosTheta, c) tmp = cosTheta * (sqrt(single(pi)) + ((cosTheta * single(pi)) * (sqrt((single(1.0) / single(pi))) + single(-1.0)))); end
\begin{array}{l}
\\
cosTheta \cdot \left(\sqrt{\pi} + \left(cosTheta \cdot \pi\right) \cdot \left(\sqrt{\frac{1}{\pi}} + -1\right)\right)
\end{array}
Initial program 98.0%
add-cube-cbrt98.0%
cbrt-unprod98.0%
frac-times98.2%
metadata-eval98.2%
add-sqr-sqrt98.2%
inv-pow98.2%
sqrt-pow298.2%
metadata-eval98.2%
Applied egg-rr98.2%
Taylor expanded in c around 0 98.0%
neg-mul-198.0%
cancel-sign-sub-inv98.0%
metadata-eval98.0%
*-commutative98.0%
Simplified98.0%
Taylor expanded in cosTheta around 0 96.4%
mul-1-neg96.4%
unsub-neg96.4%
associate-*r*96.4%
*-commutative96.4%
mul-1-neg96.4%
unsub-neg96.4%
Simplified96.4%
Final simplification96.4%
(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 98.0%
add-cube-cbrt98.0%
cbrt-unprod98.0%
frac-times98.2%
metadata-eval98.2%
add-sqr-sqrt98.2%
inv-pow98.2%
sqrt-pow298.2%
metadata-eval98.2%
Applied egg-rr98.2%
Taylor expanded in cosTheta around 0 94.2%
Final simplification94.2%
(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/98.5%
*-un-lft-identity98.5%
sub-neg98.5%
sub-neg98.5%
add-sqr-sqrt-0.0%
sqrt-unprod93.8%
sqr-neg93.8%
sqrt-unprod93.8%
add-sqr-sqrt93.8%
add-sqr-sqrt-0.0%
sqrt-unprod93.3%
sqr-neg93.3%
sqrt-unprod93.3%
add-sqr-sqrt93.3%
Applied egg-rr93.3%
Taylor expanded in cosTheta around 0 93.8%
Taylor expanded in cosTheta around inf 10.4%
Taylor expanded in c around 0 10.4%
mul-1-neg10.4%
unsub-neg10.4%
Simplified10.4%
Final simplification10.4%
(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/98.5%
*-un-lft-identity98.5%
sub-neg98.5%
sub-neg98.5%
add-sqr-sqrt-0.0%
sqrt-unprod93.8%
sqr-neg93.8%
sqrt-unprod93.8%
add-sqr-sqrt93.8%
add-sqr-sqrt-0.0%
sqrt-unprod93.3%
sqr-neg93.3%
sqrt-unprod93.3%
add-sqr-sqrt93.3%
Applied egg-rr93.3%
Taylor expanded in cosTheta around 0 93.8%
Taylor expanded in cosTheta around inf 10.4%
Taylor expanded in c around 0 10.4%
Final simplification10.4%
herbie shell --seed 2024059
(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))))))