
(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 10 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 (fma (/ (/ (sqrt (+ 1.0 (* cosTheta -2.0))) cosTheta) (sqrt PI)) (pow (exp cosTheta) (- cosTheta)) (+ 1.0 c))))
float code(float cosTheta, float c) {
return 1.0f / fmaf(((sqrtf((1.0f + (cosTheta * -2.0f))) / cosTheta) / sqrtf(((float) M_PI))), powf(expf(cosTheta), -cosTheta), (1.0f + c));
}
function code(cosTheta, c) return Float32(Float32(1.0) / fma(Float32(Float32(sqrt(Float32(Float32(1.0) + Float32(cosTheta * Float32(-2.0)))) / cosTheta) / sqrt(Float32(pi))), (exp(cosTheta) ^ Float32(-cosTheta)), Float32(Float32(1.0) + c))) end
\begin{array}{l}
\\
\frac{1}{\mathsf{fma}\left(\frac{\frac{\sqrt{1 + cosTheta \cdot -2}}{cosTheta}}{\sqrt{\pi}}, {\left(e^{cosTheta}\right)}^{\left(-cosTheta\right)}, 1 + c\right)}
\end{array}
Initial program 98.0%
+-commutative98.0%
fma-define98.1%
associate-*l/98.7%
*-lft-identity98.7%
associate--l-98.7%
sub-neg98.7%
neg-mul-198.7%
distribute-lft-out98.7%
distribute-rgt-out98.7%
metadata-eval98.7%
distribute-lft-neg-out98.7%
distribute-rgt-neg-out98.7%
exp-prod98.7%
Simplified98.7%
Final simplification98.7%
(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-define98.1%
times-frac98.7%
*-lft-identity98.7%
associate--l-98.7%
sub-neg98.7%
neg-mul-198.7%
distribute-lft-out98.7%
distribute-rgt-out98.7%
metadata-eval98.7%
exp-prod98.7%
Simplified98.7%
Final simplification98.7%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(*
(/ (* (pow PI -0.5) (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), -0.5f) * 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(pi) ^ Float32(-0.5)) * sqrt(Float32(Float32(1.0) - Float32(cosTheta + cosTheta)))) / cosTheta) * exp(Float32(cosTheta * Float32(-cosTheta)))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / ((single(1.0) + c) + ((((single(pi) ^ single(-0.5)) * sqrt((single(1.0) - (cosTheta + cosTheta)))) / cosTheta) * exp((cosTheta * -cosTheta)))); end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + \frac{{\pi}^{-0.5} \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-times97.9%
metadata-eval97.9%
add-sqr-sqrt97.9%
inv-pow97.9%
sqrt-pow297.9%
metadata-eval97.9%
Applied egg-rr97.9%
associate-*r/98.1%
cbrt-unprod98.2%
inv-pow98.2%
metadata-eval98.2%
pow-prod-up98.2%
add-cbrt-cube98.2%
associate--l-98.1%
Applied egg-rr98.1%
Final simplification98.1%
(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 98.0%
+-commutative98.0%
fma-define98.1%
associate-*l/98.7%
*-lft-identity98.7%
associate--l-98.7%
sub-neg98.7%
neg-mul-198.7%
distribute-lft-out98.7%
distribute-rgt-out98.7%
metadata-eval98.7%
distribute-lft-neg-out98.7%
distribute-rgt-neg-out98.7%
exp-prod98.7%
Simplified98.7%
Taylor expanded in c around 0 98.1%
Final simplification98.1%
(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-times97.9%
metadata-eval97.9%
add-sqr-sqrt97.9%
inv-pow97.9%
sqrt-pow297.9%
metadata-eval97.9%
Applied egg-rr97.9%
associate-*r/98.1%
cbrt-unprod98.2%
inv-pow98.2%
metadata-eval98.2%
pow-prod-up98.2%
add-cbrt-cube98.2%
associate--l-98.1%
Applied egg-rr98.1%
Taylor expanded in c around 0 97.6%
neg-mul-197.6%
sub-neg97.6%
*-commutative97.6%
distribute-rgt-neg-in97.6%
metadata-eval97.6%
Simplified97.6%
Final simplification97.6%
(FPCore (cosTheta c) :precision binary32 (* cosTheta (+ (sqrt PI) (* PI (* cosTheta (+ (sqrt (/ 1.0 PI)) (- -1.0 c)))))))
float code(float cosTheta, float c) {
return cosTheta * (sqrtf(((float) M_PI)) + (((float) M_PI) * (cosTheta * (sqrtf((1.0f / ((float) M_PI))) + (-1.0f - c)))));
}
function code(cosTheta, c) return Float32(cosTheta * Float32(sqrt(Float32(pi)) + Float32(Float32(pi) * Float32(cosTheta * Float32(sqrt(Float32(Float32(1.0) / Float32(pi))) + Float32(Float32(-1.0) - c)))))) end
function tmp = code(cosTheta, c) tmp = cosTheta * (sqrt(single(pi)) + (single(pi) * (cosTheta * (sqrt((single(1.0) / single(pi))) + (single(-1.0) - c))))); end
\begin{array}{l}
\\
cosTheta \cdot \left(\sqrt{\pi} + \pi \cdot \left(cosTheta \cdot \left(\sqrt{\frac{1}{\pi}} + \left(-1 - c\right)\right)\right)\right)
\end{array}
Initial program 98.0%
associate-+l+98.0%
+-commutative98.0%
fma-define98.1%
times-frac98.7%
*-lft-identity98.7%
associate--l-98.7%
sub-neg98.7%
neg-mul-198.7%
distribute-lft-out98.7%
distribute-rgt-out98.7%
metadata-eval98.7%
exp-prod98.7%
Simplified98.7%
Taylor expanded in cosTheta around 0 96.1%
mul-1-neg96.1%
unsub-neg96.1%
associate-*r*96.1%
*-commutative96.1%
associate-*l*96.1%
associate-+r+96.1%
mul-1-neg96.1%
unsub-neg96.1%
Simplified96.1%
Final simplification96.1%
(FPCore (cosTheta c) :precision binary32 (* cosTheta (- (sqrt PI) (* c (* cosTheta PI)))))
float code(float cosTheta, float c) {
return cosTheta * (sqrtf(((float) M_PI)) - (c * (cosTheta * ((float) M_PI))));
}
function code(cosTheta, c) return Float32(cosTheta * Float32(sqrt(Float32(pi)) - Float32(c * Float32(cosTheta * Float32(pi))))) end
function tmp = code(cosTheta, c) tmp = cosTheta * (sqrt(single(pi)) - (c * (cosTheta * single(pi)))); end
\begin{array}{l}
\\
cosTheta \cdot \left(\sqrt{\pi} - c \cdot \left(cosTheta \cdot \pi\right)\right)
\end{array}
Initial program 98.0%
add-sqr-sqrt97.4%
sqrt-unprod55.1%
associate-*l/55.2%
*-un-lft-identity55.2%
associate-*l/55.4%
*-un-lft-identity55.4%
frac-times55.0%
Applied egg-rr49.9%
associate-/l/50.2%
+-commutative50.2%
+-commutative50.2%
Simplified50.2%
Taylor expanded in cosTheta around 0 93.4%
mul-1-neg93.4%
associate-*r*93.4%
*-commutative93.4%
+-commutative93.4%
Simplified93.4%
Taylor expanded in c around inf 94.1%
unsub-neg94.1%
*-commutative94.1%
Applied egg-rr94.1%
Final simplification94.1%
(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%
+-commutative98.0%
fma-define98.1%
associate-*l/98.7%
*-lft-identity98.7%
associate--l-98.7%
sub-neg98.7%
neg-mul-198.7%
distribute-lft-out98.7%
distribute-rgt-out98.7%
metadata-eval98.7%
distribute-lft-neg-out98.7%
distribute-rgt-neg-out98.7%
exp-prod98.7%
Simplified98.7%
Taylor expanded in c around 0 98.1%
Taylor expanded in cosTheta around 0 94.1%
Final simplification94.1%
(FPCore (cosTheta c) :precision binary32 (* (- cosTheta) (* c (* cosTheta PI))))
float code(float cosTheta, float c) {
return -cosTheta * (c * (cosTheta * ((float) M_PI)));
}
function code(cosTheta, c) return Float32(Float32(-cosTheta) * Float32(c * Float32(cosTheta * Float32(pi)))) end
function tmp = code(cosTheta, c) tmp = -cosTheta * (c * (cosTheta * single(pi))); end
\begin{array}{l}
\\
\left(-cosTheta\right) \cdot \left(c \cdot \left(cosTheta \cdot \pi\right)\right)
\end{array}
Initial program 98.0%
add-sqr-sqrt97.4%
sqrt-unprod55.1%
associate-*l/55.2%
*-un-lft-identity55.2%
associate-*l/55.4%
*-un-lft-identity55.4%
frac-times55.0%
Applied egg-rr49.9%
associate-/l/50.2%
+-commutative50.2%
+-commutative50.2%
Simplified50.2%
Taylor expanded in cosTheta around 0 93.4%
mul-1-neg93.4%
associate-*r*93.4%
*-commutative93.4%
+-commutative93.4%
Simplified93.4%
Taylor expanded in c around inf 94.1%
Taylor expanded in cosTheta around inf 11.1%
mul-1-neg11.1%
*-commutative11.1%
*-commutative11.1%
distribute-lft-neg-out11.1%
*-commutative11.1%
distribute-rgt-neg-in11.1%
Simplified11.1%
Final simplification11.1%
(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}
\\
\frac{1}{c}
\end{array}
Initial program 98.0%
associate-+l+98.0%
+-commutative98.0%
fma-define98.1%
times-frac98.7%
*-lft-identity98.7%
associate--l-98.7%
sub-neg98.7%
neg-mul-198.7%
distribute-lft-out98.7%
distribute-rgt-out98.7%
metadata-eval98.7%
exp-prod98.7%
Simplified98.7%
Taylor expanded in c around inf 4.9%
Final simplification4.9%
herbie shell --seed 2024069
(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))))))