
(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 97.8%
associate-+l+97.8%
+-commutative97.8%
fma-define97.8%
times-frac98.3%
*-lft-identity98.3%
associate--l-98.4%
sub-neg98.4%
neg-mul-198.4%
distribute-lft-out98.4%
distribute-rgt-out98.4%
metadata-eval98.4%
exp-prod98.4%
Simplified98.4%
Final simplification98.4%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
1.0
(*
(exp (- (pow cosTheta 2.0)))
(/ (sqrt (/ (+ 1.0 (* cosTheta -2.0)) PI)) cosTheta)))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (expf(-powf(cosTheta, 2.0f)) * (sqrtf(((1.0f + (cosTheta * -2.0f)) / ((float) M_PI))) / cosTheta)));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(exp(Float32(-(cosTheta ^ Float32(2.0)))) * Float32(sqrt(Float32(Float32(Float32(1.0) + Float32(cosTheta * Float32(-2.0))) / Float32(pi))) / cosTheta)))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (single(1.0) + (exp(-(cosTheta ^ single(2.0))) * (sqrt(((single(1.0) + (cosTheta * single(-2.0))) / single(pi))) / cosTheta))); end
\begin{array}{l}
\\
\frac{1}{1 + e^{-{cosTheta}^{2}} \cdot \frac{\sqrt{\frac{1 + cosTheta \cdot -2}{\pi}}}{cosTheta}}
\end{array}
Initial program 97.8%
Taylor expanded in c around 0 97.8%
associate-*l/97.8%
mul-1-neg97.8%
cancel-sign-sub-inv97.8%
metadata-eval97.8%
Applied egg-rr97.8%
associate-/l*97.8%
*-commutative97.8%
Simplified97.8%
Final simplification97.8%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
1.0
(*
(sqrt (/ (+ 1.0 (* cosTheta -2.0)) PI))
(/ (exp (- (pow cosTheta 2.0))) cosTheta)))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (sqrtf(((1.0f + (cosTheta * -2.0f)) / ((float) M_PI))) * (expf(-powf(cosTheta, 2.0f)) / 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(-(cosTheta ^ Float32(2.0)))) / 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 ^ single(2.0))) / cosTheta))); end
\begin{array}{l}
\\
\frac{1}{1 + \sqrt{\frac{1 + cosTheta \cdot -2}{\pi}} \cdot \frac{e^{-{cosTheta}^{2}}}{cosTheta}}
\end{array}
Initial program 97.8%
*-un-lft-identity97.8%
inv-pow97.8%
sqrt-pow297.8%
metadata-eval97.8%
Applied egg-rr97.8%
*-lft-identity97.8%
Simplified97.8%
Taylor expanded in c around 0 97.8%
*-commutative97.8%
*-commutative97.8%
cancel-sign-sub-inv97.8%
distribute-lft-neg-in97.8%
distribute-rgt-neg-in97.8%
metadata-eval97.8%
neg-mul-197.8%
Simplified97.8%
Final simplification97.8%
(FPCore (cosTheta c) :precision binary32 (* cosTheta (- (sqrt PI) (* (* cosTheta PI) (- (+ 1.0 c) (pow PI -0.5))))))
float code(float cosTheta, float c) {
return cosTheta * (sqrtf(((float) M_PI)) - ((cosTheta * ((float) M_PI)) * ((1.0f + c) - powf(((float) M_PI), -0.5f))));
}
function code(cosTheta, c) return Float32(cosTheta * Float32(sqrt(Float32(pi)) - Float32(Float32(cosTheta * Float32(pi)) * Float32(Float32(Float32(1.0) + c) - (Float32(pi) ^ Float32(-0.5)))))) end
function tmp = code(cosTheta, c) tmp = cosTheta * (sqrt(single(pi)) - ((cosTheta * single(pi)) * ((single(1.0) + c) - (single(pi) ^ single(-0.5))))); end
\begin{array}{l}
\\
cosTheta \cdot \left(\sqrt{\pi} - \left(cosTheta \cdot \pi\right) \cdot \left(\left(1 + c\right) - {\pi}^{-0.5}\right)\right)
\end{array}
Initial program 97.8%
associate-+l+97.8%
+-commutative97.8%
fma-define97.8%
times-frac98.3%
*-lft-identity98.3%
associate--l-98.4%
sub-neg98.4%
neg-mul-198.4%
distribute-lft-out98.4%
distribute-rgt-out98.4%
metadata-eval98.4%
exp-prod98.4%
Simplified98.4%
Taylor expanded in cosTheta around 0 96.4%
mul-1-neg96.4%
unsub-neg96.4%
Simplified96.4%
Taylor expanded in cosTheta around 0 96.4%
mul-1-neg96.4%
unsub-neg96.4%
associate-*r*96.4%
*-commutative96.4%
associate-+r+96.4%
mul-1-neg96.4%
unsub-neg96.4%
Simplified96.4%
*-un-lft-identity96.4%
pow1/296.4%
inv-pow96.4%
pow-pow96.4%
metadata-eval96.4%
Applied egg-rr96.4%
*-lft-identity96.4%
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 97.8%
Taylor expanded in c around 0 97.8%
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 (/ 1.0 (+ 1.0 (/ (* (sqrt (/ 1.0 PI)) (- 1.0 cosTheta)) cosTheta))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + ((sqrtf((1.0f / ((float) M_PI))) * (1.0f - cosTheta)) / cosTheta));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(Float32(sqrt(Float32(Float32(1.0) / Float32(pi))) * Float32(Float32(1.0) - cosTheta)) / cosTheta))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (single(1.0) + ((sqrt((single(1.0) / single(pi))) * (single(1.0) - cosTheta)) / cosTheta)); end
\begin{array}{l}
\\
\frac{1}{1 + \frac{\sqrt{\frac{1}{\pi}} \cdot \left(1 - cosTheta\right)}{cosTheta}}
\end{array}
Initial program 97.8%
*-un-lft-identity97.8%
inv-pow97.8%
sqrt-pow297.8%
metadata-eval97.8%
Applied egg-rr97.8%
*-lft-identity97.8%
Simplified97.8%
Taylor expanded in c around 0 97.8%
*-commutative97.8%
*-commutative97.8%
cancel-sign-sub-inv97.8%
distribute-lft-neg-in97.8%
distribute-rgt-neg-in97.8%
metadata-eval97.8%
neg-mul-197.8%
Simplified97.8%
Taylor expanded in cosTheta around 0 95.6%
associate-*r*95.6%
neg-mul-195.6%
distribute-rgt1-in95.5%
Simplified95.5%
Final simplification95.5%
(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%
Taylor expanded in c around 0 97.8%
Taylor expanded in cosTheta around 0 93.9%
Final simplification93.9%
(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 97.8%
associate-+l+97.8%
+-commutative97.8%
fma-define97.8%
times-frac98.3%
*-lft-identity98.3%
associate--l-98.4%
sub-neg98.4%
neg-mul-198.4%
distribute-lft-out98.4%
distribute-rgt-out98.4%
metadata-eval98.4%
exp-prod98.4%
Simplified98.4%
Taylor expanded in cosTheta around 0 96.4%
mul-1-neg96.4%
unsub-neg96.4%
Simplified96.4%
Taylor expanded in c around inf 10.6%
Taylor expanded in c around 0 10.6%
mul-1-neg10.6%
unsub-neg10.6%
Simplified10.6%
Final simplification10.6%
(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%
fma-define97.8%
times-frac98.3%
*-lft-identity98.3%
associate--l-98.4%
sub-neg98.4%
neg-mul-198.4%
distribute-lft-out98.4%
distribute-rgt-out98.4%
metadata-eval98.4%
exp-prod98.4%
Simplified98.4%
Taylor expanded in cosTheta around 0 96.4%
mul-1-neg96.4%
unsub-neg96.4%
Simplified96.4%
Taylor expanded in c around inf 10.6%
Taylor expanded in c around 0 10.6%
Final simplification10.6%
herbie shell --seed 2024080
(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))))))