
(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 c)
(/
(/ (sqrt (+ 1.0 (* cosTheta -2.0))) (* cosTheta (sqrt PI)))
(exp (* cosTheta cosTheta))))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + ((sqrtf((1.0f + (cosTheta * -2.0f))) / (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 * Float32(-2.0)))) / Float32(cosTheta * sqrt(Float32(pi)))) / exp(Float32(cosTheta * cosTheta))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / ((single(1.0) + c) + ((sqrt((single(1.0) + (cosTheta * single(-2.0)))) / (cosTheta * sqrt(single(pi)))) / exp((cosTheta * cosTheta)))); end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + \frac{\frac{\sqrt{1 + cosTheta \cdot -2}}{cosTheta \cdot \sqrt{\pi}}}{e^{cosTheta \cdot cosTheta}}}
\end{array}
Initial program 98.2%
distribute-lft-neg-out98.2%
exp-neg98.1%
associate-*r/98.1%
associate-/l*98.1%
/-rgt-identity98.1%
*-commutative98.1%
Simplified98.6%
Final simplification98.6%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
1.0
(*
(/ 1.0 (* cosTheta (exp (pow cosTheta 2.0))))
(sqrt (/ (+ 1.0 (* cosTheta -2.0)) PI))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + ((1.0f / (cosTheta * expf(powf(cosTheta, 2.0f)))) * sqrtf(((1.0f + (cosTheta * -2.0f)) / ((float) M_PI)))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(Float32(Float32(1.0) / Float32(cosTheta * exp((cosTheta ^ Float32(2.0))))) * 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) + ((single(1.0) / (cosTheta * exp((cosTheta ^ single(2.0))))) * sqrt(((single(1.0) + (cosTheta * single(-2.0))) / single(pi))))); end
\begin{array}{l}
\\
\frac{1}{1 + \frac{1}{cosTheta \cdot e^{{cosTheta}^{2}}} \cdot \sqrt{\frac{1 + cosTheta \cdot -2}{\pi}}}
\end{array}
Initial program 98.2%
distribute-lft-neg-out98.2%
exp-neg98.1%
associate-*r/98.1%
associate-/l*98.1%
/-rgt-identity98.1%
*-commutative98.1%
Simplified98.6%
Taylor expanded in c around 0 98.1%
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 98.2%
Taylor expanded in c around 0 98.1%
Final simplification98.1%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(*
(/ 1.0 (/ (sqrt PI) (+ -1.0 (+ (* cosTheta -0.5) (/ 1.0 cosTheta)))))
(exp (* cosTheta (- cosTheta)))))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + ((1.0f / (sqrtf(((float) M_PI)) / (-1.0f + ((cosTheta * -0.5f) + (1.0f / cosTheta))))) * expf((cosTheta * -cosTheta))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(Float32(Float32(1.0) / Float32(sqrt(Float32(pi)) / Float32(Float32(-1.0) + Float32(Float32(cosTheta * Float32(-0.5)) + Float32(Float32(1.0) / cosTheta))))) * exp(Float32(cosTheta * Float32(-cosTheta)))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / ((single(1.0) + c) + ((single(1.0) / (sqrt(single(pi)) / (single(-1.0) + ((cosTheta * single(-0.5)) + (single(1.0) / cosTheta))))) * exp((cosTheta * -cosTheta)))); end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + \frac{1}{\frac{\sqrt{\pi}}{-1 + \left(cosTheta \cdot -0.5 + \frac{1}{cosTheta}\right)}} \cdot e^{cosTheta \cdot \left(-cosTheta\right)}}
\end{array}
Initial program 98.2%
Applied egg-rr98.6%
Taylor expanded in cosTheta around 0 97.4%
Final simplification97.4%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(*
(exp (* cosTheta (- cosTheta)))
(/ (+ -1.0 (+ (* cosTheta -0.5) (/ 1.0 cosTheta))) (sqrt PI))))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + (expf((cosTheta * -cosTheta)) * ((-1.0f + ((cosTheta * -0.5f) + (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(cosTheta * Float32(-0.5)) + 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) + ((cosTheta * single(-0.5)) + (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 + \left(cosTheta \cdot -0.5 + \frac{1}{cosTheta}\right)}{\sqrt{\pi}}}
\end{array}
Initial program 98.2%
frac-times98.7%
*-un-lft-identity98.7%
add-log-exp97.2%
associate--l-97.2%
exp-diff97.2%
prod-exp97.1%
exp-lft-sqr97.2%
*-commutative97.2%
exp-diff97.2%
add-log-exp98.6%
associate-/l/98.6%
Applied egg-rr98.6%
Taylor expanded in cosTheta around 0 97.4%
Final simplification97.4%
(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 98.2%
frac-times98.7%
*-un-lft-identity98.7%
add-log-exp97.2%
associate--l-97.2%
exp-diff97.2%
prod-exp97.1%
exp-lft-sqr97.2%
*-commutative97.2%
exp-diff97.2%
add-log-exp98.6%
associate-/l/98.6%
Applied egg-rr98.6%
Taylor expanded in cosTheta around 0 96.3%
Final simplification96.3%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(/
(/ (- 1.0 cosTheta) (* cosTheta (sqrt PI)))
(exp (* cosTheta cosTheta))))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + (((1.0f - 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(Float32(Float32(1.0) - cosTheta) / Float32(cosTheta * sqrt(Float32(pi)))) / exp(Float32(cosTheta * cosTheta))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / ((single(1.0) + c) + (((single(1.0) - cosTheta) / (cosTheta * sqrt(single(pi)))) / exp((cosTheta * cosTheta)))); end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + \frac{\frac{1 - cosTheta}{cosTheta \cdot \sqrt{\pi}}}{e^{cosTheta \cdot cosTheta}}}
\end{array}
Initial program 98.2%
distribute-lft-neg-out98.2%
exp-neg98.1%
associate-*r/98.1%
associate-/l*98.1%
/-rgt-identity98.1%
*-commutative98.1%
Simplified98.6%
Taylor expanded in cosTheta around 0 96.2%
mul-1-neg96.2%
unsub-neg96.2%
Simplified96.2%
Final simplification96.2%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (+ 1.0 (+ c (* (sqrt (/ 1.0 PI)) (+ -1.0 (/ 1.0 cosTheta)))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (c + (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(c + 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) + (c + (sqrt((single(1.0) / single(pi))) * (single(-1.0) + (single(1.0) / cosTheta))))); end
\begin{array}{l}
\\
\frac{1}{1 + \left(c + \sqrt{\frac{1}{\pi}} \cdot \left(-1 + \frac{1}{cosTheta}\right)\right)}
\end{array}
Initial program 98.2%
+-commutative98.2%
fma-def98.2%
associate-*l/98.7%
*-commutative98.7%
*-rgt-identity98.7%
associate--l-98.6%
count-298.6%
*-commutative98.6%
exp-prod98.6%
Simplified98.6%
Taylor expanded in cosTheta around 0 95.4%
+-commutative95.4%
distribute-rgt-out95.4%
Simplified95.4%
Final simplification95.4%
(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 98.2%
Taylor expanded in cosTheta around 0 92.4%
Final simplification92.4%
(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 98.2%
Taylor expanded in cosTheta around inf 11.0%
Taylor expanded in c around 0 11.0%
mul-1-neg11.0%
unsub-neg11.0%
Simplified11.0%
Final simplification11.0%
(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 98.2%
distribute-lft-neg-out98.2%
exp-neg98.1%
associate-*r/98.1%
associate-/l*98.1%
/-rgt-identity98.1%
*-commutative98.1%
Simplified98.6%
Taylor expanded in c around 0 98.1%
Taylor expanded in cosTheta around inf 11.0%
Final simplification11.0%
herbie shell --seed 2023319
(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))))))