
(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 11 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 97.7%
associate-+l+97.7%
+-commutative97.7%
fma-define97.7%
Simplified98.6%
Final simplification98.6%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
1.0
(+
c
(*
(/ (exp (* cosTheta (- cosTheta))) cosTheta)
(sqrt (/ (+ 1.0 (* cosTheta -2.0)) PI)))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (c + ((expf((cosTheta * -cosTheta)) / 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(-cosTheta))) / 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 * -cosTheta)) / cosTheta) * sqrt(((single(1.0) + (cosTheta * single(-2.0))) / single(pi)))))); end
\begin{array}{l}
\\
\frac{1}{1 + \left(c + \frac{e^{cosTheta \cdot \left(-cosTheta\right)}}{cosTheta} \cdot \sqrt{\frac{1 + cosTheta \cdot -2}{\pi}}\right)}
\end{array}
Initial program 97.7%
associate-+l+97.7%
+-commutative97.7%
fma-define97.7%
Simplified98.6%
Taylor expanded in c around 0 97.9%
unpow297.9%
Applied egg-rr97.9%
Final simplification97.9%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(-
1.0
(-
(*
(sqrt (/ (+ 1.0 (* cosTheta -2.0)) PI))
(/ (+ -1.0 (pow cosTheta 2.0)) cosTheta))
c))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f - ((sqrtf(((1.0f + (cosTheta * -2.0f)) / ((float) M_PI))) * ((-1.0f + powf(cosTheta, 2.0f)) / cosTheta)) - c));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) - Float32(Float32(sqrt(Float32(Float32(Float32(1.0) + Float32(cosTheta * Float32(-2.0))) / Float32(pi))) * Float32(Float32(Float32(-1.0) + (cosTheta ^ Float32(2.0))) / cosTheta)) - c))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (single(1.0) - ((sqrt(((single(1.0) + (cosTheta * single(-2.0))) / single(pi))) * ((single(-1.0) + (cosTheta ^ single(2.0))) / cosTheta)) - c)); end
\begin{array}{l}
\\
\frac{1}{1 - \left(\sqrt{\frac{1 + cosTheta \cdot -2}{\pi}} \cdot \frac{-1 + {cosTheta}^{2}}{cosTheta} - c\right)}
\end{array}
Initial program 97.7%
associate-+l+97.7%
+-commutative97.7%
fma-define97.7%
Simplified98.6%
Taylor expanded in c around 0 97.9%
Taylor expanded in cosTheta around 0 96.8%
neg-mul-196.8%
sub-neg96.8%
Simplified96.8%
Final simplification96.8%
(FPCore (cosTheta c) :precision binary32 (* cosTheta (- (sqrt PI) (* (* cosTheta PI) (- (+ 1.0 c) (sqrt (/ 1.0 PI)))))))
float code(float cosTheta, float c) {
return cosTheta * (sqrtf(((float) M_PI)) - ((cosTheta * ((float) M_PI)) * ((1.0f + c) - sqrtf((1.0f / ((float) M_PI))))));
}
function code(cosTheta, c) return Float32(cosTheta * Float32(sqrt(Float32(pi)) - Float32(Float32(cosTheta * Float32(pi)) * Float32(Float32(Float32(1.0) + c) - sqrt(Float32(Float32(1.0) / Float32(pi))))))) end
function tmp = code(cosTheta, c) tmp = cosTheta * (sqrt(single(pi)) - ((cosTheta * single(pi)) * ((single(1.0) + c) - sqrt((single(1.0) / single(pi)))))); end
\begin{array}{l}
\\
cosTheta \cdot \left(\sqrt{\pi} - \left(cosTheta \cdot \pi\right) \cdot \left(\left(1 + c\right) - \sqrt{\frac{1}{\pi}}\right)\right)
\end{array}
Initial program 97.7%
associate-+l+97.7%
+-commutative97.7%
fma-define97.7%
Simplified98.6%
Taylor expanded in cosTheta around 0 95.4%
mul-1-neg95.4%
unsub-neg95.4%
associate-*r*95.4%
associate-+r+95.4%
mul-1-neg95.4%
unsub-neg95.4%
Simplified95.4%
(FPCore (cosTheta c) :precision binary32 (* cosTheta (+ (sqrt PI) (* (* cosTheta PI) (+ -1.0 (sqrt (/ 1.0 PI)))))))
float code(float cosTheta, float c) {
return cosTheta * (sqrtf(((float) M_PI)) + ((cosTheta * ((float) M_PI)) * (-1.0f + sqrtf((1.0f / ((float) M_PI))))));
}
function code(cosTheta, c) return Float32(cosTheta * Float32(sqrt(Float32(pi)) + Float32(Float32(cosTheta * Float32(pi)) * Float32(Float32(-1.0) + sqrt(Float32(Float32(1.0) / Float32(pi))))))) end
function tmp = code(cosTheta, c) tmp = cosTheta * (sqrt(single(pi)) + ((cosTheta * single(pi)) * (single(-1.0) + sqrt((single(1.0) / single(pi)))))); end
\begin{array}{l}
\\
cosTheta \cdot \left(\sqrt{\pi} + \left(cosTheta \cdot \pi\right) \cdot \left(-1 + \sqrt{\frac{1}{\pi}}\right)\right)
\end{array}
Initial program 97.7%
Taylor expanded in c around 0 97.2%
Taylor expanded in cosTheta around 0 95.2%
mul-1-neg95.2%
unsub-neg95.2%
associate-*r*95.2%
mul-1-neg95.2%
unsub-neg95.2%
Simplified95.2%
Final simplification95.2%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (+ 1.0 (+ c (* (sqrt (/ (+ 1.0 (* cosTheta -2.0)) PI)) (/ 1.0 cosTheta))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (c + (sqrtf(((1.0f + (cosTheta * -2.0f)) / ((float) M_PI))) * (1.0f / cosTheta))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(c + Float32(sqrt(Float32(Float32(Float32(1.0) + Float32(cosTheta * Float32(-2.0))) / Float32(pi))) * Float32(Float32(1.0) / cosTheta))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (single(1.0) + (c + (sqrt(((single(1.0) + (cosTheta * single(-2.0))) / single(pi))) * (single(1.0) / cosTheta)))); end
\begin{array}{l}
\\
\frac{1}{1 + \left(c + \sqrt{\frac{1 + cosTheta \cdot -2}{\pi}} \cdot \frac{1}{cosTheta}\right)}
\end{array}
Initial program 97.7%
associate-+l+97.7%
+-commutative97.7%
fma-define97.7%
Simplified98.6%
Taylor expanded in c around 0 97.9%
Taylor expanded in cosTheta around 0 94.8%
Final simplification94.8%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (+ 1.0 (+ c (/ -1.0 (/ cosTheta (* (pow PI -0.5) (+ cosTheta -1.0))))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (c + (-1.0f / (cosTheta / (powf(((float) M_PI), -0.5f) * (cosTheta + -1.0f))))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(c + Float32(Float32(-1.0) / Float32(cosTheta / Float32((Float32(pi) ^ Float32(-0.5)) * Float32(cosTheta + Float32(-1.0)))))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (single(1.0) + (c + (single(-1.0) / (cosTheta / ((single(pi) ^ single(-0.5)) * (cosTheta + single(-1.0))))))); end
\begin{array}{l}
\\
\frac{1}{1 + \left(c + \frac{-1}{\frac{cosTheta}{{\pi}^{-0.5} \cdot \left(cosTheta + -1\right)}}\right)}
\end{array}
Initial program 97.7%
associate-+l+97.7%
+-commutative97.7%
fma-define97.7%
Simplified98.6%
Taylor expanded in c around 0 97.9%
Taylor expanded in cosTheta around 0 94.7%
mul-1-neg94.7%
unsub-neg94.7%
Simplified94.7%
+-commutative94.7%
*-un-lft-identity94.7%
fma-define94.7%
pow1/294.7%
inv-pow94.7%
pow-pow94.7%
metadata-eval94.7%
pow1/294.7%
inv-pow94.7%
pow-pow94.7%
metadata-eval94.7%
Applied egg-rr94.7%
fma-undefine94.7%
*-lft-identity94.7%
cancel-sign-sub-inv94.7%
distribute-rgt1-in94.7%
Simplified94.7%
clear-num94.7%
inv-pow94.7%
neg-mul-194.7%
fma-define94.7%
Applied egg-rr94.7%
Simplified94.7%
Final simplification94.7%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (+ 1.0 (+ c (* (- 1.0 cosTheta) (/ (pow PI -0.5) cosTheta))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (c + ((1.0f - cosTheta) * (powf(((float) M_PI), -0.5f) / cosTheta))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(c + Float32(Float32(Float32(1.0) - cosTheta) * Float32((Float32(pi) ^ Float32(-0.5)) / cosTheta))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (single(1.0) + (c + ((single(1.0) - cosTheta) * ((single(pi) ^ single(-0.5)) / cosTheta)))); end
\begin{array}{l}
\\
\frac{1}{1 + \left(c + \left(1 - cosTheta\right) \cdot \frac{{\pi}^{-0.5}}{cosTheta}\right)}
\end{array}
Initial program 97.7%
associate-+l+97.7%
+-commutative97.7%
fma-define97.7%
Simplified98.6%
Taylor expanded in c around 0 97.9%
Taylor expanded in cosTheta around 0 94.7%
mul-1-neg94.7%
unsub-neg94.7%
Simplified94.7%
+-commutative94.7%
*-un-lft-identity94.7%
fma-define94.7%
pow1/294.7%
inv-pow94.7%
pow-pow94.7%
metadata-eval94.7%
pow1/294.7%
inv-pow94.7%
pow-pow94.7%
metadata-eval94.7%
Applied egg-rr94.7%
fma-undefine94.7%
*-lft-identity94.7%
cancel-sign-sub-inv94.7%
distribute-rgt1-in94.7%
Simplified94.7%
*-un-lft-identity94.7%
associate-/l*94.7%
neg-mul-194.7%
fma-define94.7%
Applied egg-rr94.7%
Simplified94.7%
Final simplification94.7%
(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 97.7%
associate-+l+97.7%
+-commutative97.7%
fma-define97.7%
Simplified98.6%
Taylor expanded in c around 0 97.9%
Taylor expanded in cosTheta around 0 94.7%
mul-1-neg94.7%
unsub-neg94.7%
Simplified94.7%
Taylor expanded in c around 0 94.3%
associate--l+94.3%
sub-neg94.3%
mul-1-neg94.3%
+-commutative94.3%
distribute-rgt-out94.3%
Simplified94.3%
(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%
Taylor expanded in c around 0 97.2%
log1p-expm1-u97.2%
+-commutative97.2%
*-commutative97.2%
distribute-lft-neg-out97.2%
unpow297.2%
mul-1-neg97.2%
fma-define97.2%
Applied egg-rr98.1%
Taylor expanded in cosTheta around 0 92.1%
(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-define97.7%
Simplified98.6%
Taylor expanded in c around inf 11.0%
Taylor expanded in c around 0 11.0%
herbie shell --seed 2024172
(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))))))