
(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 (fma cosTheta -2.0 1.0))
(/ (* cosTheta (pow PI 0.16666666666666666)) (cbrt (/ 1.0 PI))))
(exp (* cosTheta (- cosTheta)))))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + ((sqrtf(fmaf(cosTheta, -2.0f, 1.0f)) / ((cosTheta * powf(((float) M_PI), 0.16666666666666666f)) / cbrtf((1.0f / ((float) M_PI))))) * expf((cosTheta * -cosTheta))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(Float32(sqrt(fma(cosTheta, Float32(-2.0), Float32(1.0))) / Float32(Float32(cosTheta * (Float32(pi) ^ Float32(0.16666666666666666))) / cbrt(Float32(Float32(1.0) / Float32(pi))))) * exp(Float32(cosTheta * Float32(-cosTheta)))))) end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + \frac{\sqrt{\mathsf{fma}\left(cosTheta, -2, 1\right)}}{\frac{cosTheta \cdot {\pi}^{0.16666666666666666}}{\sqrt[3]{\frac{1}{\pi}}}} \cdot e^{cosTheta \cdot \left(-cosTheta\right)}}
\end{array}
Initial program 97.7%
frac-times98.5%
Applied egg-rr98.5%
*-commutative98.5%
associate-/r*98.2%
un-div-inv98.2%
add-cbrt-cube98.2%
add-sqr-sqrt98.2%
cbrt-prod98.2%
frac-times98.4%
associate-*l/98.3%
div-inv98.4%
Applied egg-rr98.4%
associate-*l/98.7%
unpow1/396.6%
associate-/l*96.6%
unpow1/398.6%
Simplified98.6%
Final simplification98.6%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(*
(exp (* cosTheta (- cosTheta)))
(/ (sqrt (fma cosTheta -2.0 1.0)) (* cosTheta (sqrt PI)))))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + (expf((cosTheta * -cosTheta)) * (sqrtf(fmaf(cosTheta, -2.0f, 1.0f)) / (cosTheta * sqrtf(((float) M_PI))))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(exp(Float32(cosTheta * Float32(-cosTheta))) * Float32(sqrt(fma(cosTheta, Float32(-2.0), Float32(1.0))) / Float32(cosTheta * sqrt(Float32(pi))))))) end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + e^{cosTheta \cdot \left(-cosTheta\right)} \cdot \frac{\sqrt{\mathsf{fma}\left(cosTheta, -2, 1\right)}}{cosTheta \cdot \sqrt{\pi}}}
\end{array}
Initial program 97.7%
frac-times98.5%
Applied egg-rr98.5%
Final simplification98.5%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
c
(+
1.0
(/
(sqrt (/ (fma cosTheta -2.0 1.0) PI))
(* cosTheta (exp (pow cosTheta 2.0))))))))
float code(float cosTheta, float c) {
return 1.0f / (c + (1.0f + (sqrtf((fmaf(cosTheta, -2.0f, 1.0f) / ((float) M_PI))) / (cosTheta * expf(powf(cosTheta, 2.0f))))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(c + Float32(Float32(1.0) + Float32(sqrt(Float32(fma(cosTheta, Float32(-2.0), Float32(1.0)) / Float32(pi))) / Float32(cosTheta * exp((cosTheta ^ Float32(2.0)))))))) end
\begin{array}{l}
\\
\frac{1}{c + \left(1 + \frac{\sqrt{\frac{\mathsf{fma}\left(cosTheta, -2, 1\right)}{\pi}}}{cosTheta \cdot e^{{cosTheta}^{2}}}\right)}
\end{array}
Initial program 97.7%
+-commutative97.7%
fma-def97.7%
associate-*l/98.2%
*-lft-identity98.2%
sub-neg98.2%
sub-neg98.2%
associate-+l+98.2%
neg-mul-198.2%
neg-mul-198.2%
distribute-rgt-out98.2%
metadata-eval98.2%
exp-prod98.2%
Simplified98.2%
Applied egg-rr98.1%
Final simplification98.1%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(*
(exp (* cosTheta (- cosTheta)))
(/ (sqrt (/ (fma cosTheta -2.0 1.0) PI)) cosTheta)))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + (expf((cosTheta * -cosTheta)) * (sqrtf((fmaf(cosTheta, -2.0f, 1.0f) / ((float) M_PI))) / cosTheta)));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(exp(Float32(cosTheta * Float32(-cosTheta))) * Float32(sqrt(Float32(fma(cosTheta, Float32(-2.0), Float32(1.0)) / Float32(pi))) / cosTheta)))) end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + e^{cosTheta \cdot \left(-cosTheta\right)} \cdot \frac{\sqrt{\frac{\mathsf{fma}\left(cosTheta, -2, 1\right)}{\pi}}}{cosTheta}}
\end{array}
Initial program 97.7%
frac-times98.5%
Applied egg-rr98.5%
*-un-lft-identity98.5%
*-un-lft-identity98.5%
associate-/r*98.1%
*-un-lft-identity98.1%
sqrt-undiv98.1%
Applied egg-rr98.1%
*-lft-identity98.1%
Simplified98.1%
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 97.7%
associate-+l+97.7%
+-commutative97.7%
*-commutative97.7%
associate-*l*97.7%
fma-def97.6%
Simplified97.6%
Taylor expanded in c around 0 97.3%
Final simplification97.3%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(*
(exp (* cosTheta (- cosTheta)))
(/ (+ -1.0 (/ 1.0 cosTheta)) (sqrt PI))))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + (expf((cosTheta * -cosTheta)) * ((-1.0f + (1.0f / cosTheta)) / sqrtf(((float) M_PI)))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(exp(Float32(cosTheta * Float32(-cosTheta))) * 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) + (exp((cosTheta * -cosTheta)) * ((single(-1.0) + (single(1.0) / cosTheta)) / sqrt(single(pi))))); end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + e^{cosTheta \cdot \left(-cosTheta\right)} \cdot \frac{-1 + \frac{1}{cosTheta}}{\sqrt{\pi}}}
\end{array}
Initial program 97.7%
frac-times98.5%
Applied egg-rr98.5%
Taylor expanded in cosTheta around 0 95.5%
distribute-rgt-out95.4%
Simplified95.4%
sqrt-div95.4%
metadata-eval95.4%
associate-*l/96.0%
*-un-lft-identity96.0%
Applied egg-rr96.0%
Final simplification96.0%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (+ 1.0 (* (+ -1.0 (/ 1.0 cosTheta)) (sqrt (/ 1.0 PI))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + ((-1.0f + (1.0f / cosTheta)) * sqrtf((1.0f / ((float) M_PI)))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(Float32(Float32(-1.0) + Float32(Float32(1.0) / cosTheta)) * sqrt(Float32(Float32(1.0) / Float32(pi)))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (single(1.0) + ((single(-1.0) + (single(1.0) / cosTheta)) * sqrt((single(1.0) / single(pi))))); end
\begin{array}{l}
\\
\frac{1}{1 + \left(-1 + \frac{1}{cosTheta}\right) \cdot \sqrt{\frac{1}{\pi}}}
\end{array}
Initial program 97.7%
associate-+l+97.7%
+-commutative97.7%
fma-def97.7%
Simplified98.5%
Taylor expanded in cosTheta around 0 95.2%
Taylor expanded in c around 0 95.1%
distribute-rgt-out95.0%
Simplified95.0%
Final simplification95.0%
(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(Float32(1.0) + 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}{\left(1 + c\right) + \frac{-1 + \frac{1}{cosTheta}}{\sqrt{\pi}}}
\end{array}
Initial program 97.7%
associate-+l+97.7%
+-commutative97.7%
fma-def97.7%
Simplified98.5%
Taylor expanded in cosTheta around 0 95.2%
div-inv95.2%
associate-+r+95.2%
distribute-rgt-out95.1%
sqrt-div95.1%
metadata-eval95.1%
associate-*l/95.7%
*-un-lft-identity95.7%
+-commutative95.7%
Applied egg-rr95.7%
*-lft-identity95.7%
+-commutative95.7%
Simplified95.7%
Final simplification95.7%
(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 97.7%
frac-times98.5%
Applied egg-rr98.5%
Taylor expanded in cosTheta around 0 94.0%
Final simplification94.0%
(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 97.7%
associate-+l+97.7%
+-commutative97.7%
fma-def97.7%
Simplified98.5%
Taylor expanded in cosTheta around inf 10.5%
Taylor expanded in c around 0 10.5%
Final simplification10.5%
herbie shell --seed 2023301
(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))))))