
(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 12 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 97.5%
frac-times98.4%
*-un-lft-identity98.4%
associate--l-98.4%
*-commutative98.4%
Applied egg-rr98.4%
Final simplification98.4%
(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 97.5%
associate-+l+97.5%
+-commutative97.5%
*-commutative97.5%
associate-*l*97.5%
fma-def97.5%
Simplified97.5%
Taylor expanded in c around 0 97.6%
Final simplification97.6%
(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 97.5%
associate-+l+97.5%
+-commutative97.5%
*-commutative97.5%
associate-*l*97.5%
fma-def97.5%
Simplified97.5%
Taylor expanded in c around 0 96.9%
Final simplification96.9%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(*
(exp (* cosTheta (- cosTheta)))
(/ (+ (+ (* cosTheta -0.5) (/ 1.0 cosTheta)) -1.0) (sqrt PI))))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + (expf((cosTheta * -cosTheta)) * ((((cosTheta * -0.5f) + (1.0f / cosTheta)) + -1.0f) / 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(Float32(cosTheta * Float32(-0.5)) + Float32(Float32(1.0) / cosTheta)) + Float32(-1.0)) / sqrt(Float32(pi)))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / ((single(1.0) + c) + (exp((cosTheta * -cosTheta)) * ((((cosTheta * single(-0.5)) + (single(1.0) / cosTheta)) + single(-1.0)) / sqrt(single(pi))))); end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + e^{cosTheta \cdot \left(-cosTheta\right)} \cdot \frac{\left(cosTheta \cdot -0.5 + \frac{1}{cosTheta}\right) + -1}{\sqrt{\pi}}}
\end{array}
Initial program 97.5%
associate-*l/97.9%
*-un-lft-identity97.9%
associate--l-98.0%
Applied egg-rr98.0%
Taylor expanded in cosTheta around 0 95.7%
Final simplification95.7%
(FPCore (cosTheta c)
:precision binary32
(let* ((t_0 (sqrt (/ 1.0 PI))))
(/
1.0
(+ 1.0 (+ (* t_0 (+ (/ 1.0 cosTheta) -1.0)) (* cosTheta (* t_0 -1.5)))))))
float code(float cosTheta, float c) {
float t_0 = sqrtf((1.0f / ((float) M_PI)));
return 1.0f / (1.0f + ((t_0 * ((1.0f / cosTheta) + -1.0f)) + (cosTheta * (t_0 * -1.5f))));
}
function code(cosTheta, c) t_0 = sqrt(Float32(Float32(1.0) / Float32(pi))) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(Float32(t_0 * Float32(Float32(Float32(1.0) / cosTheta) + Float32(-1.0))) + Float32(cosTheta * Float32(t_0 * Float32(-1.5)))))) end
function tmp = code(cosTheta, c) t_0 = sqrt((single(1.0) / single(pi))); tmp = single(1.0) / (single(1.0) + ((t_0 * ((single(1.0) / cosTheta) + single(-1.0))) + (cosTheta * (t_0 * single(-1.5))))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{\frac{1}{\pi}}\\
\frac{1}{1 + \left(t\_0 \cdot \left(\frac{1}{cosTheta} + -1\right) + cosTheta \cdot \left(t\_0 \cdot -1.5\right)\right)}
\end{array}
\end{array}
Initial program 97.5%
associate-+l+97.5%
+-commutative97.5%
*-commutative97.5%
associate-*l*97.5%
fma-def97.5%
Simplified97.5%
Taylor expanded in c around 0 96.9%
Taylor expanded in cosTheta around 0 95.1%
+-commutative95.1%
associate-+r+95.1%
distribute-rgt-out95.1%
distribute-rgt-out95.1%
metadata-eval95.1%
Simplified95.1%
Final simplification95.1%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(*
(exp (* cosTheta (- cosTheta)))
(/ (- 1.0 cosTheta) (* cosTheta (sqrt PI)))))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + (expf((cosTheta * -cosTheta)) * ((1.0f - cosTheta) / (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) - cosTheta) / Float32(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) / (cosTheta * sqrt(single(pi)))))); end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + e^{cosTheta \cdot \left(-cosTheta\right)} \cdot \frac{1 - cosTheta}{cosTheta \cdot \sqrt{\pi}}}
\end{array}
Initial program 97.5%
frac-times98.4%
*-un-lft-identity98.4%
associate--l-98.4%
*-commutative98.4%
Applied egg-rr98.4%
Taylor expanded in cosTheta around 0 94.9%
mul-1-neg94.9%
unsub-neg94.9%
Simplified94.9%
Final simplification94.9%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (+ 1.0 (fma (pow PI -0.5) (+ (/ 1.0 cosTheta) -1.0) c))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + fmaf(powf(((float) M_PI), -0.5f), ((1.0f / cosTheta) + -1.0f), c));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + fma((Float32(pi) ^ Float32(-0.5)), Float32(Float32(Float32(1.0) / cosTheta) + Float32(-1.0)), c))) end
\begin{array}{l}
\\
\frac{1}{1 + \mathsf{fma}\left({\pi}^{-0.5}, \frac{1}{cosTheta} + -1, c\right)}
\end{array}
Initial program 97.5%
associate-+l+97.5%
+-commutative97.5%
*-commutative97.5%
associate-*l*97.5%
fma-def97.5%
Simplified97.5%
Taylor expanded in cosTheta around 0 93.8%
+-commutative93.8%
distribute-rgt-out93.7%
fma-def93.7%
Simplified93.7%
expm1-log1p-u93.7%
expm1-udef93.7%
pow1/293.7%
inv-pow93.7%
pow-pow93.7%
metadata-eval93.7%
Applied egg-rr93.7%
expm1-def93.7%
expm1-log1p93.7%
Simplified93.7%
Final simplification93.7%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (+ 1.0 (+ c (* (+ (/ 1.0 cosTheta) -1.0) (pow PI -0.5))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (c + (((1.0f / cosTheta) + -1.0f) * powf(((float) M_PI), -0.5f))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(c + Float32(Float32(Float32(Float32(1.0) / cosTheta) + Float32(-1.0)) * (Float32(pi) ^ Float32(-0.5)))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (single(1.0) + (c + (((single(1.0) / cosTheta) + single(-1.0)) * (single(pi) ^ single(-0.5))))); end
\begin{array}{l}
\\
\frac{1}{1 + \left(c + \left(\frac{1}{cosTheta} + -1\right) \cdot {\pi}^{-0.5}\right)}
\end{array}
Initial program 97.5%
associate-+l+97.5%
+-commutative97.5%
*-commutative97.5%
associate-*l*97.5%
fma-def97.5%
Simplified97.5%
Taylor expanded in cosTheta around 0 93.8%
+-commutative93.8%
distribute-rgt-out93.7%
fma-def93.7%
Simplified93.7%
fma-udef93.7%
pow1/293.7%
inv-pow93.7%
pow-pow93.7%
metadata-eval93.7%
Applied egg-rr93.7%
Final simplification93.7%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (+ 1.0 (* (sqrt (/ 1.0 PI)) (+ (/ 1.0 cosTheta) -1.0)))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (sqrtf((1.0f / ((float) M_PI))) * ((1.0f / cosTheta) + -1.0f)));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(sqrt(Float32(Float32(1.0) / Float32(pi))) * Float32(Float32(Float32(1.0) / cosTheta) + Float32(-1.0))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (single(1.0) + (sqrt((single(1.0) / single(pi))) * ((single(1.0) / cosTheta) + single(-1.0)))); end
\begin{array}{l}
\\
\frac{1}{1 + \sqrt{\frac{1}{\pi}} \cdot \left(\frac{1}{cosTheta} + -1\right)}
\end{array}
Initial program 97.5%
associate-+l+97.5%
+-commutative97.5%
*-commutative97.5%
associate-*l*97.5%
fma-def97.5%
Simplified97.5%
Taylor expanded in cosTheta around 0 93.8%
+-commutative93.8%
distribute-rgt-out93.7%
fma-def93.7%
Simplified93.7%
Taylor expanded in c around 0 93.5%
Final simplification93.5%
(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 97.5%
associate-+l+97.5%
+-commutative97.5%
*-commutative97.5%
associate-*l*97.5%
fma-def97.5%
Simplified97.5%
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 97.5%
associate-+l+97.5%
+-commutative97.5%
*-commutative97.5%
associate-*l*97.5%
fma-def97.5%
Simplified97.5%
Taylor expanded in cosTheta around inf 10.9%
Taylor expanded in c around 0 10.9%
mul-1-neg10.9%
unsub-neg10.9%
Simplified10.9%
Final simplification10.9%
(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 97.5%
associate-+l+97.5%
+-commutative97.5%
*-commutative97.5%
associate-*l*97.5%
fma-def97.5%
Simplified97.5%
Taylor expanded in cosTheta around inf 10.9%
Taylor expanded in c around 0 10.9%
Final simplification10.9%
herbie shell --seed 2024031
(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))))))