
(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 7 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 97.6%
frac-times98.6%
*-un-lft-identity98.6%
associate--r+98.6%
Applied egg-rr98.6%
Final simplification98.6%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
1.0
(/
(sqrt (/ (+ 1.0 (* cosTheta -2.0)) PI))
(* cosTheta (exp (* cosTheta cosTheta)))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (sqrtf(((1.0f + (cosTheta * -2.0f)) / ((float) M_PI))) / (cosTheta * expf((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(cosTheta * exp(Float32(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))) / (cosTheta * exp((cosTheta * cosTheta))))); end
\begin{array}{l}
\\
\frac{1}{1 + \frac{\sqrt{\frac{1 + cosTheta \cdot -2}{\pi}}}{cosTheta \cdot e^{cosTheta \cdot cosTheta}}}
\end{array}
Initial program 97.6%
+-commutative97.6%
associate-+l+97.6%
distribute-lft-neg-out97.6%
exp-neg97.6%
associate-*r/97.7%
associate-/l*97.7%
/-rgt-identity97.7%
Simplified98.5%
Taylor expanded in c around 0 97.2%
un-div-inv97.6%
*-commutative97.6%
*-commutative97.6%
pow297.6%
Applied egg-rr97.6%
Final simplification97.6%
(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 97.6%
associate-*l*97.6%
*-lft-identity97.6%
associate-*r*97.6%
*-lft-identity97.6%
associate--l-97.6%
*-commutative97.6%
Simplified97.6%
associate-*l/98.3%
*-un-lft-identity98.3%
associate-*l/98.3%
Applied egg-rr98.3%
Taylor expanded in cosTheta around 0 96.5%
Final simplification96.5%
(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 97.6%
associate-*l*97.6%
*-lft-identity97.6%
associate-*r*97.6%
*-lft-identity97.6%
associate--l-97.6%
*-commutative97.6%
Simplified97.6%
associate-*l/98.3%
*-un-lft-identity98.3%
associate-*l/98.3%
Applied egg-rr98.3%
Taylor expanded in cosTheta around 0 95.0%
Final simplification95.0%
(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 97.6%
frac-times98.6%
*-un-lft-identity98.6%
associate--r+98.6%
Applied egg-rr98.6%
Taylor expanded in cosTheta around 0 92.6%
Final simplification92.6%
(FPCore (cosTheta c) :precision binary32 (* c (* (* cosTheta cosTheta) (- PI))))
float code(float cosTheta, float c) {
return c * ((cosTheta * cosTheta) * -((float) M_PI));
}
function code(cosTheta, c) return Float32(c * Float32(Float32(cosTheta * cosTheta) * Float32(-Float32(pi)))) end
function tmp = code(cosTheta, c) tmp = c * ((cosTheta * cosTheta) * -single(pi)); end
\begin{array}{l}
\\
c \cdot \left(\left(cosTheta \cdot cosTheta\right) \cdot \left(-\pi\right)\right)
\end{array}
Initial program 97.6%
frac-times98.6%
*-un-lft-identity98.6%
associate--r+98.6%
Applied egg-rr98.6%
Taylor expanded in cosTheta around 0 95.3%
fma-def95.4%
associate-*r*95.4%
mul-1-neg95.4%
unpow295.4%
*-commutative95.4%
mul-1-neg95.4%
sub-neg95.4%
Simplified95.4%
Taylor expanded in c around inf 10.8%
associate-*r*10.8%
mul-1-neg10.8%
unpow210.8%
Simplified10.8%
Final simplification10.8%
(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 97.6%
+-commutative97.6%
associate-+l+97.6%
distribute-lft-neg-out97.6%
exp-neg97.6%
associate-*r/97.7%
associate-/l*97.7%
/-rgt-identity97.7%
Simplified98.5%
Taylor expanded in c around 0 97.2%
+-commutative97.2%
associate-*r/97.6%
metadata-eval97.6%
cancel-sign-sub-inv97.6%
*-rgt-identity97.6%
cancel-sign-sub-inv97.6%
metadata-eval97.6%
+-commutative97.6%
*-commutative97.6%
fma-udef97.6%
*-commutative97.6%
unpow297.6%
Simplified97.6%
Taylor expanded in cosTheta around inf 10.8%
Final simplification10.8%
herbie shell --seed 2023174
(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))))))