
(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
(+
(+ 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 97.8%
frac-times98.6%
*-un-lft-identity98.6%
associate--r+98.7%
Applied egg-rr98.7%
Final simplification98.7%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
1.0
(+
c
(/
(+
(fma cosTheta -1.5 (fma cosTheta (* cosTheta 0.5) -1.0))
(/ 1.0 cosTheta))
(sqrt PI))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (c + ((fmaf(cosTheta, -1.5f, fmaf(cosTheta, (cosTheta * 0.5f), -1.0f)) + (1.0f / cosTheta)) / sqrtf(((float) M_PI)))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(c + Float32(Float32(fma(cosTheta, Float32(-1.5), fma(cosTheta, Float32(cosTheta * Float32(0.5)), Float32(-1.0))) + Float32(Float32(1.0) / cosTheta)) / sqrt(Float32(pi)))))) end
\begin{array}{l}
\\
\frac{1}{1 + \left(c + \frac{\mathsf{fma}\left(cosTheta, -1.5, \mathsf{fma}\left(cosTheta, cosTheta \cdot 0.5, -1\right)\right) + \frac{1}{cosTheta}}{\sqrt{\pi}}\right)}
\end{array}
Initial program 97.8%
associate-+l+97.8%
associate-*l*97.8%
associate-*l/98.2%
*-lft-identity98.2%
Simplified98.2%
Taylor expanded in cosTheta around 0 97.5%
pow197.5%
unpow297.5%
Applied egg-rr97.5%
unpow197.5%
unpow297.5%
*-commutative97.5%
unpow297.5%
Simplified97.5%
Taylor expanded in cosTheta around 0 97.5%
sub-neg97.5%
fma-def97.5%
*-commutative97.5%
unpow297.5%
fma-udef97.5%
metadata-eval97.5%
+-commutative97.5%
fma-udef97.5%
fma-udef97.5%
unpow297.5%
*-commutative97.5%
associate-+r+97.5%
associate-+r+97.5%
Simplified97.5%
Final simplification97.5%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
1.0
(+
c
(/
(+
-1.0
(+ (* cosTheta -1.5) (+ (/ 1.0 cosTheta) (* 0.5 (* cosTheta cosTheta)))))
(sqrt PI))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (c + ((-1.0f + ((cosTheta * -1.5f) + ((1.0f / cosTheta) + (0.5f * (cosTheta * cosTheta))))) / sqrtf(((float) M_PI)))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(c + Float32(Float32(Float32(-1.0) + Float32(Float32(cosTheta * Float32(-1.5)) + Float32(Float32(Float32(1.0) / cosTheta) + Float32(Float32(0.5) * Float32(cosTheta * cosTheta))))) / sqrt(Float32(pi)))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (single(1.0) + (c + ((single(-1.0) + ((cosTheta * single(-1.5)) + ((single(1.0) / cosTheta) + (single(0.5) * (cosTheta * cosTheta))))) / sqrt(single(pi))))); end
\begin{array}{l}
\\
\frac{1}{1 + \left(c + \frac{-1 + \left(cosTheta \cdot -1.5 + \left(\frac{1}{cosTheta} + 0.5 \cdot \left(cosTheta \cdot cosTheta\right)\right)\right)}{\sqrt{\pi}}\right)}
\end{array}
Initial program 97.8%
associate-+l+97.8%
associate-*l*97.8%
associate-*l/98.2%
*-lft-identity98.2%
Simplified98.2%
Taylor expanded in cosTheta around 0 97.5%
pow197.5%
unpow297.5%
Applied egg-rr97.5%
unpow197.5%
unpow297.5%
*-commutative97.5%
unpow297.5%
Simplified97.5%
Final simplification97.5%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (+ 1.0 (+ c (/ (+ -1.0 (+ (/ 1.0 cosTheta) (* cosTheta -1.5))) (sqrt PI))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (c + ((-1.0f + ((1.0f / cosTheta) + (cosTheta * -1.5f))) / sqrtf(((float) M_PI)))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(c + Float32(Float32(Float32(-1.0) + Float32(Float32(Float32(1.0) / cosTheta) + Float32(cosTheta * Float32(-1.5)))) / sqrt(Float32(pi)))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (single(1.0) + (c + ((single(-1.0) + ((single(1.0) / cosTheta) + (cosTheta * single(-1.5)))) / sqrt(single(pi))))); end
\begin{array}{l}
\\
\frac{1}{1 + \left(c + \frac{-1 + \left(\frac{1}{cosTheta} + cosTheta \cdot -1.5\right)}{\sqrt{\pi}}\right)}
\end{array}
Initial program 97.8%
associate-+l+97.8%
associate-*l*97.8%
associate-*l/98.2%
*-lft-identity98.2%
Simplified98.2%
Taylor expanded in cosTheta around 0 97.1%
Final simplification97.1%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (+ 1.0 (* (sqrt (/ 1.0 PI)) (+ -1.0 (/ 1.0 cosTheta))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (sqrtf((1.0f / ((float) M_PI))) * (-1.0f + (1.0f / cosTheta))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(sqrt(Float32(Float32(1.0) / Float32(pi))) * Float32(Float32(-1.0) + Float32(Float32(1.0) / cosTheta))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (single(1.0) + (sqrt((single(1.0) / single(pi))) * (single(-1.0) + (single(1.0) / cosTheta)))); end
\begin{array}{l}
\\
\frac{1}{1 + \sqrt{\frac{1}{\pi}} \cdot \left(-1 + \frac{1}{cosTheta}\right)}
\end{array}
Initial program 97.8%
frac-times98.6%
*-un-lft-identity98.6%
associate--r+98.7%
Applied egg-rr98.7%
Taylor expanded in c around 0 97.1%
fma-def97.2%
mul-1-neg97.2%
unpow297.2%
cancel-sign-sub-inv97.2%
metadata-eval97.2%
Simplified97.2%
Taylor expanded in cosTheta around 0 95.2%
distribute-rgt-out95.2%
Simplified95.2%
Final simplification95.2%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (+ 1.0 (+ c (/ (+ -1.0 (/ 1.0 cosTheta)) (sqrt PI))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (c + ((-1.0f + (1.0f / cosTheta)) / sqrtf(((float) M_PI)))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(c + Float32(Float32(Float32(-1.0) + Float32(Float32(1.0) / cosTheta)) / sqrt(Float32(pi)))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (single(1.0) + (c + ((single(-1.0) + (single(1.0) / cosTheta)) / sqrt(single(pi))))); end
\begin{array}{l}
\\
\frac{1}{1 + \left(c + \frac{-1 + \frac{1}{cosTheta}}{\sqrt{\pi}}\right)}
\end{array}
Initial program 97.8%
associate-+l+97.8%
associate-*l*97.8%
associate-*l/98.2%
*-lft-identity98.2%
Simplified98.2%
Taylor expanded in cosTheta around 0 95.9%
Final simplification95.9%
(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%
frac-times98.6%
*-un-lft-identity98.6%
associate--r+98.7%
Applied egg-rr98.7%
Taylor expanded in cosTheta around 0 93.8%
Final simplification93.8%
(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(cosTheta * Float32(cosTheta * Float32(-Float32(pi))))) end
function tmp = code(cosTheta, c) tmp = c * (cosTheta * (cosTheta * -single(pi))); end
\begin{array}{l}
\\
c \cdot \left(cosTheta \cdot \left(cosTheta \cdot \left(-\pi\right)\right)\right)
\end{array}
Initial program 97.8%
+-commutative97.8%
associate-+l+97.8%
distribute-lft-neg-out97.8%
exp-neg97.7%
associate-*r/97.7%
associate-/l*97.7%
/-rgt-identity97.7%
Simplified98.7%
Taylor expanded in cosTheta around 0 96.4%
fma-def96.4%
associate-*r*96.4%
mul-1-neg96.4%
unpow296.4%
distribute-rgt-neg-out96.4%
*-commutative96.4%
mul-1-neg96.4%
Simplified96.4%
Taylor expanded in c around inf 10.9%
mul-1-neg10.9%
distribute-rgt-neg-in10.9%
distribute-lft-neg-out10.9%
unpow210.9%
distribute-rgt-neg-out10.9%
associate-*l*10.9%
Simplified10.9%
Final simplification10.9%
(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%
+-commutative97.8%
associate-+l+97.8%
distribute-lft-neg-out97.8%
exp-neg97.7%
associate-*r/97.7%
associate-/l*97.7%
/-rgt-identity97.7%
Simplified98.7%
Taylor expanded in cosTheta around inf 10.6%
Taylor expanded in c around 0 10.6%
+-commutative10.6%
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%
+-commutative97.8%
associate-+l+97.8%
distribute-lft-neg-out97.8%
exp-neg97.7%
associate-*r/97.7%
associate-/l*97.7%
/-rgt-identity97.7%
Simplified98.7%
Taylor expanded in cosTheta around inf 10.6%
Taylor expanded in c around 0 10.6%
Final simplification10.6%
herbie shell --seed 2023172
(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))))))