
(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
(let* ((t_0 (sqrt (/ 1.0 PI)))
(t_1 (- t_0 c))
(t_2 (- 1.0 t_1))
(t_3 (sqrt (pow PI 3.0)))
(t_4 (* t_0 -1.5))
(t_5 (fma PI t_4 (* (pow t_2 2.0) (- t_3)))))
(+
(-
(+
(* cosTheta (sqrt PI))
(*
(pow cosTheta 4.0)
(+
(* t_5 (* (sqrt PI) t_2))
(- (* t_2 (* t_4 t_3)) (* 0.5 (* PI t_0))))))
(* t_5 (pow cosTheta 3.0)))
(* PI (* (pow cosTheta 2.0) (+ -1.0 t_1))))))
float code(float cosTheta, float c) {
float t_0 = sqrtf((1.0f / ((float) M_PI)));
float t_1 = t_0 - c;
float t_2 = 1.0f - t_1;
float t_3 = sqrtf(powf(((float) M_PI), 3.0f));
float t_4 = t_0 * -1.5f;
float t_5 = fmaf(((float) M_PI), t_4, (powf(t_2, 2.0f) * -t_3));
return (((cosTheta * sqrtf(((float) M_PI))) + (powf(cosTheta, 4.0f) * ((t_5 * (sqrtf(((float) M_PI)) * t_2)) + ((t_2 * (t_4 * t_3)) - (0.5f * (((float) M_PI) * t_0)))))) - (t_5 * powf(cosTheta, 3.0f))) + (((float) M_PI) * (powf(cosTheta, 2.0f) * (-1.0f + t_1)));
}
function code(cosTheta, c) t_0 = sqrt(Float32(Float32(1.0) / Float32(pi))) t_1 = Float32(t_0 - c) t_2 = Float32(Float32(1.0) - t_1) t_3 = sqrt((Float32(pi) ^ Float32(3.0))) t_4 = Float32(t_0 * Float32(-1.5)) t_5 = fma(Float32(pi), t_4, Float32((t_2 ^ Float32(2.0)) * Float32(-t_3))) return Float32(Float32(Float32(Float32(cosTheta * sqrt(Float32(pi))) + Float32((cosTheta ^ Float32(4.0)) * Float32(Float32(t_5 * Float32(sqrt(Float32(pi)) * t_2)) + Float32(Float32(t_2 * Float32(t_4 * t_3)) - Float32(Float32(0.5) * Float32(Float32(pi) * t_0)))))) - Float32(t_5 * (cosTheta ^ Float32(3.0)))) + Float32(Float32(pi) * Float32((cosTheta ^ Float32(2.0)) * Float32(Float32(-1.0) + t_1)))) end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{\frac{1}{\pi}}\\
t_1 := t_0 - c\\
t_2 := 1 - t_1\\
t_3 := \sqrt{{\pi}^{3}}\\
t_4 := t_0 \cdot -1.5\\
t_5 := \mathsf{fma}\left(\pi, t_4, {t_2}^{2} \cdot \left(-t_3\right)\right)\\
\left(\left(cosTheta \cdot \sqrt{\pi} + {cosTheta}^{4} \cdot \left(t_5 \cdot \left(\sqrt{\pi} \cdot t_2\right) + \left(t_2 \cdot \left(t_4 \cdot t_3\right) - 0.5 \cdot \left(\pi \cdot t_0\right)\right)\right)\right) - t_5 \cdot {cosTheta}^{3}\right) + \pi \cdot \left({cosTheta}^{2} \cdot \left(-1 + t_1\right)\right)
\end{array}
\end{array}
Initial program 96.9%
+-commutative96.9%
associate-+l+96.9%
*-commutative96.9%
associate-*l*96.9%
/-rgt-identity96.9%
associate-/r/96.8%
exp-neg96.9%
distribute-rgt-neg-out96.9%
Simplified97.7%
Taylor expanded in cosTheta around 0 97.8%
Simplified97.8%
Final simplification97.8%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
c
(+
1.0
(/
(/ (sqrt (+ 1.0 (* cosTheta -2.0))) (* cosTheta (sqrt PI)))
(pow (exp cosTheta) cosTheta))))))
float code(float cosTheta, float c) {
return 1.0f / (c + (1.0f + ((sqrtf((1.0f + (cosTheta * -2.0f))) / (cosTheta * sqrtf(((float) M_PI)))) / powf(expf(cosTheta), cosTheta))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(c + Float32(Float32(1.0) + Float32(Float32(sqrt(Float32(Float32(1.0) + Float32(cosTheta * Float32(-2.0)))) / Float32(cosTheta * sqrt(Float32(pi)))) / (exp(cosTheta) ^ cosTheta))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (c + (single(1.0) + ((sqrt((single(1.0) + (cosTheta * single(-2.0)))) / (cosTheta * sqrt(single(pi)))) / (exp(cosTheta) ^ cosTheta)))); end
\begin{array}{l}
\\
\frac{1}{c + \left(1 + \frac{\frac{\sqrt{1 + cosTheta \cdot -2}}{cosTheta \cdot \sqrt{\pi}}}{{\left(e^{cosTheta}\right)}^{cosTheta}}\right)}
\end{array}
Initial program 96.9%
+-commutative96.9%
associate-+l+96.9%
*-commutative96.9%
associate-*l*96.9%
/-rgt-identity96.9%
associate-/r/96.8%
exp-neg96.9%
distribute-rgt-neg-out96.9%
Simplified97.7%
Final simplification97.7%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
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 / (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(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}{1 + \frac{\sqrt{\frac{\mathsf{fma}\left(cosTheta, -2, 1\right)}{\pi}}}{cosTheta \cdot e^{{cosTheta}^{2}}}}
\end{array}
Initial program 96.9%
+-commutative96.9%
associate-+l+96.9%
*-commutative96.9%
associate-*l*96.9%
/-rgt-identity96.9%
associate-/r/96.8%
exp-neg96.9%
distribute-rgt-neg-out96.9%
Simplified97.7%
Taylor expanded in c around 0 96.8%
+-commutative96.8%
*-commutative96.8%
fma-udef96.8%
associate-*l/97.2%
*-lft-identity97.2%
Simplified97.2%
Final simplification97.2%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
1.0
(+
c
(*
(/ (exp (- (pow cosTheta 2.0))) cosTheta)
(sqrt (/ (+ 1.0 (* cosTheta -2.0)) PI)))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (c + ((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(c + 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) + (c + ((exp(-(cosTheta ^ single(2.0))) / cosTheta) * sqrt(((single(1.0) + (cosTheta * single(-2.0))) / single(pi)))))); end
\begin{array}{l}
\\
\frac{1}{1 + \left(c + \frac{e^{-{cosTheta}^{2}}}{cosTheta} \cdot \sqrt{\frac{1 + cosTheta \cdot -2}{\pi}}\right)}
\end{array}
Initial program 96.9%
+-commutative96.9%
fma-def96.9%
Simplified97.4%
Taylor expanded in c around 0 97.0%
Final simplification97.0%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
1.0
(*
(sqrt (/ (+ 1.0 (* cosTheta -2.0)) PI))
(/ 1.0 (* cosTheta (exp (pow cosTheta 2.0))))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (sqrtf(((1.0f + (cosTheta * -2.0f)) / ((float) M_PI))) * (1.0f / (cosTheta * expf(powf(cosTheta, 2.0f))))));
}
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(Float32(1.0) / Float32(cosTheta * exp((cosTheta ^ Float32(2.0)))))))) 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 * exp((cosTheta ^ single(2.0))))))); end
\begin{array}{l}
\\
\frac{1}{1 + \sqrt{\frac{1 + cosTheta \cdot -2}{\pi}} \cdot \frac{1}{cosTheta \cdot e^{{cosTheta}^{2}}}}
\end{array}
Initial program 96.9%
+-commutative96.9%
associate-+l+96.9%
*-commutative96.9%
associate-*l*96.9%
/-rgt-identity96.9%
associate-/r/96.8%
exp-neg96.9%
distribute-rgt-neg-out96.9%
Simplified97.7%
Taylor expanded in c around 0 96.8%
Final simplification96.8%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
c
(+
1.0
(/
(/ (- 1.0 cosTheta) (* cosTheta (sqrt PI)))
(pow (exp cosTheta) cosTheta))))))
float code(float cosTheta, float c) {
return 1.0f / (c + (1.0f + (((1.0f - cosTheta) / (cosTheta * sqrtf(((float) M_PI)))) / powf(expf(cosTheta), cosTheta))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(c + Float32(Float32(1.0) + Float32(Float32(Float32(Float32(1.0) - cosTheta) / Float32(cosTheta * sqrt(Float32(pi)))) / (exp(cosTheta) ^ cosTheta))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (c + (single(1.0) + (((single(1.0) - cosTheta) / (cosTheta * sqrt(single(pi)))) / (exp(cosTheta) ^ cosTheta)))); end
\begin{array}{l}
\\
\frac{1}{c + \left(1 + \frac{\frac{1 - cosTheta}{cosTheta \cdot \sqrt{\pi}}}{{\left(e^{cosTheta}\right)}^{cosTheta}}\right)}
\end{array}
Initial program 96.9%
+-commutative96.9%
associate-+l+96.9%
*-commutative96.9%
associate-*l*96.9%
/-rgt-identity96.9%
associate-/r/96.8%
exp-neg96.9%
distribute-rgt-neg-out96.9%
Simplified97.7%
Taylor expanded in cosTheta around 0 95.4%
mul-1-neg95.4%
unsub-neg95.4%
Simplified95.4%
Final simplification95.4%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
c
(+
1.0
(*
(* (sqrt (/ 1.0 PI)) (- 1.0 (pow cosTheta 2.0)))
(+ -1.0 (/ 1.0 cosTheta)))))))
float code(float cosTheta, float c) {
return 1.0f / (c + (1.0f + ((sqrtf((1.0f / ((float) M_PI))) * (1.0f - powf(cosTheta, 2.0f))) * (-1.0f + (1.0f / cosTheta)))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(c + Float32(Float32(1.0) + Float32(Float32(sqrt(Float32(Float32(1.0) / Float32(pi))) * Float32(Float32(1.0) - (cosTheta ^ Float32(2.0)))) * Float32(Float32(-1.0) + Float32(Float32(1.0) / cosTheta)))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (c + (single(1.0) + ((sqrt((single(1.0) / single(pi))) * (single(1.0) - (cosTheta ^ single(2.0)))) * (single(-1.0) + (single(1.0) / cosTheta))))); end
\begin{array}{l}
\\
\frac{1}{c + \left(1 + \left(\sqrt{\frac{1}{\pi}} \cdot \left(1 - {cosTheta}^{2}\right)\right) \cdot \left(-1 + \frac{1}{cosTheta}\right)\right)}
\end{array}
Initial program 96.9%
+-commutative96.9%
associate-+l+96.9%
*-commutative96.9%
associate-*l*96.9%
/-rgt-identity96.9%
associate-/r/96.8%
exp-neg96.9%
distribute-rgt-neg-out96.9%
Simplified97.7%
Taylor expanded in cosTheta around 0 94.6%
distribute-rgt-out94.6%
Simplified94.6%
*-un-lft-identity94.6%
associate-/l*94.4%
pow1/294.4%
inv-pow94.4%
pow-pow94.4%
metadata-eval94.4%
pow-exp94.4%
unpow294.4%
Applied egg-rr94.4%
*-lft-identity94.4%
associate-/r/94.5%
Simplified94.5%
Taylor expanded in cosTheta around 0 94.5%
associate-*r*94.5%
neg-mul-194.5%
distribute-rgt1-in94.5%
Simplified94.5%
Final simplification94.5%
(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 96.9%
Taylor expanded in c around 0 96.8%
Taylor expanded in cosTheta around 0 94.1%
distribute-rgt-out94.1%
Simplified94.1%
Final simplification94.1%
(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 96.9%
Taylor expanded in c around 0 96.8%
associate-*l/97.2%
mul-1-neg97.2%
cancel-sign-sub-inv97.2%
metadata-eval97.2%
*-commutative97.2%
+-commutative97.2%
fma-def97.2%
Applied egg-rr97.2%
Taylor expanded in cosTheta around 0 94.5%
associate-*r*94.5%
distribute-rgt1-in94.5%
mul-1-neg94.5%
Simplified94.5%
Final simplification94.5%
(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 96.9%
+-commutative96.9%
associate-+l+96.9%
*-commutative96.9%
associate-*l*96.9%
/-rgt-identity96.9%
associate-/r/96.8%
exp-neg96.9%
distribute-rgt-neg-out96.9%
Simplified97.7%
Taylor expanded in cosTheta around 0 92.3%
Final simplification92.3%
(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 96.9%
Taylor expanded in c around 0 96.8%
Taylor expanded in cosTheta around inf 10.8%
Final simplification10.8%
herbie shell --seed 2023310
(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))))))