
(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
(+
c
(+
1.0
(/
(/ (sqrt (fma cosTheta -2.0 1.0)) (* cosTheta (sqrt PI)))
(pow (exp cosTheta) cosTheta))))))
float code(float cosTheta, float c) {
return 1.0f / (c + (1.0f + ((sqrtf(fmaf(cosTheta, -2.0f, 1.0f)) / (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(fma(cosTheta, Float32(-2.0), Float32(1.0))) / Float32(cosTheta * sqrt(Float32(pi)))) / (exp(cosTheta) ^ cosTheta))))) end
\begin{array}{l}
\\
\frac{1}{c + \left(1 + \frac{\frac{\sqrt{\mathsf{fma}\left(cosTheta, -2, 1\right)}}{cosTheta \cdot \sqrt{\pi}}}{{\left(e^{cosTheta}\right)}^{cosTheta}}\right)}
\end{array}
Initial program 98.0%
+-commutative98.0%
associate-+l+98.0%
distribute-lft-neg-out98.0%
exp-neg98.0%
associate-*r/98.0%
associate-/l*98.0%
/-rgt-identity98.0%
Simplified98.6%
Final simplification98.6%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(/
(*
(/ (sqrt (- 1.0 (+ cosTheta cosTheta))) cosTheta)
(exp (* cosTheta (- cosTheta))))
(sqrt PI)))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + (((sqrtf((1.0f - (cosTheta + cosTheta))) / cosTheta) * expf((cosTheta * -cosTheta))) / sqrtf(((float) M_PI))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(Float32(Float32(sqrt(Float32(Float32(1.0) - Float32(cosTheta + cosTheta))) / cosTheta) * exp(Float32(cosTheta * Float32(-cosTheta)))) / sqrt(Float32(pi))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / ((single(1.0) + c) + (((sqrt((single(1.0) - (cosTheta + cosTheta))) / cosTheta) * exp((cosTheta * -cosTheta))) / sqrt(single(pi)))); end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + \frac{\frac{\sqrt{1 - \left(cosTheta + cosTheta\right)}}{cosTheta} \cdot e^{cosTheta \cdot \left(-cosTheta\right)}}{\sqrt{\pi}}}
\end{array}
Initial program 98.0%
associate-*l*98.0%
*-lft-identity98.0%
associate-*r*98.0%
*-lft-identity98.0%
associate--l-98.0%
*-commutative98.0%
Simplified98.0%
associate-*l/98.6%
*-un-lft-identity98.6%
Applied egg-rr98.6%
Final simplification98.6%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(/
(sqrt (/ (fma cosTheta -2.0 1.0) PI))
(* cosTheta (exp (* cosTheta cosTheta)))))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + (sqrtf((fmaf(cosTheta, -2.0f, 1.0f) / ((float) M_PI))) / (cosTheta * expf((cosTheta * cosTheta)))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(sqrt(Float32(fma(cosTheta, Float32(-2.0), Float32(1.0)) / Float32(pi))) / Float32(cosTheta * exp(Float32(cosTheta * cosTheta)))))) end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + \frac{\sqrt{\frac{\mathsf{fma}\left(cosTheta, -2, 1\right)}{\pi}}}{cosTheta \cdot e^{cosTheta \cdot cosTheta}}}
\end{array}
Initial program 98.0%
associate-*r/98.1%
distribute-lft-neg-out98.1%
exp-neg98.1%
times-frac98.1%
*-commutative98.1%
times-frac98.0%
associate-*l/98.0%
Simplified98.6%
Taylor expanded in c around 0 98.2%
+-commutative98.2%
+-commutative98.2%
cancel-sign-sub-inv98.2%
metadata-eval98.2%
associate-+l+98.2%
Simplified98.3%
Final simplification98.3%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
1.0
(*
(sqrt (/ (+ 1.0 (* cosTheta -2.0)) PI))
(/ (exp (* cosTheta (- cosTheta))) cosTheta)))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (sqrtf(((1.0f + (cosTheta * -2.0f)) / ((float) M_PI))) * (expf((cosTheta * -cosTheta)) / cosTheta)));
}
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(exp(Float32(cosTheta * Float32(-cosTheta))) / cosTheta)))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (single(1.0) + (sqrt(((single(1.0) + (cosTheta * single(-2.0))) / single(pi))) * (exp((cosTheta * -cosTheta)) / cosTheta))); end
\begin{array}{l}
\\
\frac{1}{1 + \sqrt{\frac{1 + cosTheta \cdot -2}{\pi}} \cdot \frac{e^{cosTheta \cdot \left(-cosTheta\right)}}{cosTheta}}
\end{array}
Initial program 98.0%
Taylor expanded in c around 0 97.6%
add-log-exp97.4%
cancel-sign-sub-inv97.4%
metadata-eval97.4%
Applied egg-rr97.4%
associate-*l/97.5%
mul-1-neg97.5%
pow297.5%
add-log-exp97.7%
*-commutative97.7%
Applied egg-rr97.7%
*-commutative97.7%
associate-*r/97.6%
distribute-rgt-neg-in97.6%
Simplified97.6%
Final simplification97.6%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
1.0
(/
(* (exp (* cosTheta (- cosTheta))) (sqrt (/ (+ 1.0 (* cosTheta -2.0)) PI)))
cosTheta))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + ((expf((cosTheta * -cosTheta)) * sqrtf(((1.0f + (cosTheta * -2.0f)) / ((float) M_PI)))) / cosTheta));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(Float32(exp(Float32(cosTheta * Float32(-cosTheta))) * sqrt(Float32(Float32(Float32(1.0) + Float32(cosTheta * Float32(-2.0))) / Float32(pi)))) / cosTheta))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (single(1.0) + ((exp((cosTheta * -cosTheta)) * sqrt(((single(1.0) + (cosTheta * single(-2.0))) / single(pi)))) / cosTheta)); end
\begin{array}{l}
\\
\frac{1}{1 + \frac{e^{cosTheta \cdot \left(-cosTheta\right)} \cdot \sqrt{\frac{1 + cosTheta \cdot -2}{\pi}}}{cosTheta}}
\end{array}
Initial program 98.0%
Taylor expanded in c around 0 97.6%
add-log-exp97.4%
cancel-sign-sub-inv97.4%
metadata-eval97.4%
Applied egg-rr97.4%
associate-*l/97.5%
mul-1-neg97.5%
pow297.5%
add-log-exp97.7%
*-commutative97.7%
Applied egg-rr97.7%
Final simplification97.7%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(/
(+
(+ (* cosTheta -1.5) (+ (* (* cosTheta cosTheta) 0.5) (/ 1.0 cosTheta)))
-1.0)
(sqrt PI)))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + ((((cosTheta * -1.5f) + (((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(Float32(Float32(Float32(cosTheta * Float32(-1.5)) + Float32(Float32(Float32(cosTheta * 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) + ((((cosTheta * single(-1.5)) + (((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) + \frac{\left(cosTheta \cdot -1.5 + \left(\left(cosTheta \cdot cosTheta\right) \cdot 0.5 + \frac{1}{cosTheta}\right)\right) + -1}{\sqrt{\pi}}}
\end{array}
Initial program 98.0%
associate-*l*98.0%
*-lft-identity98.0%
associate-*r*98.0%
*-lft-identity98.0%
associate--l-98.0%
*-commutative98.0%
Simplified98.0%
associate-*l/98.6%
*-un-lft-identity98.6%
Applied egg-rr98.6%
Taylor expanded in cosTheta around 0 97.4%
pow197.4%
pow297.4%
Applied egg-rr97.4%
unpow197.4%
unpow297.4%
*-commutative97.4%
unpow297.4%
Simplified97.4%
Final simplification97.4%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (+ 1.0 (+ c (/ (+ (+ (* cosTheta -1.5) (/ 1.0 cosTheta)) -1.0) (sqrt PI))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (c + ((((cosTheta * -1.5f) + (1.0f / cosTheta)) + -1.0f) / sqrtf(((float) M_PI)))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(c + Float32(Float32(Float32(Float32(cosTheta * Float32(-1.5)) + 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 + ((((cosTheta * single(-1.5)) + (single(1.0) / cosTheta)) + single(-1.0)) / sqrt(single(pi))))); end
\begin{array}{l}
\\
\frac{1}{1 + \left(c + \frac{\left(cosTheta \cdot -1.5 + \frac{1}{cosTheta}\right) + -1}{\sqrt{\pi}}\right)}
\end{array}
Initial program 98.0%
associate-+l+98.0%
associate-*l*98.0%
associate-*l/98.6%
*-lft-identity98.6%
Simplified98.6%
Taylor expanded in cosTheta around 0 96.9%
Final simplification96.9%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (+ 1.0 (+ c (/ (+ (/ 1.0 cosTheta) -1.0) (sqrt PI))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (c + (((1.0f / cosTheta) + -1.0f) / sqrtf(((float) M_PI)))));
}
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)) / sqrt(Float32(pi)))))) end
function tmp = code(cosTheta, c) tmp = single(1.0) / (single(1.0) + (c + (((single(1.0) / cosTheta) + single(-1.0)) / sqrt(single(pi))))); end
\begin{array}{l}
\\
\frac{1}{1 + \left(c + \frac{\frac{1}{cosTheta} + -1}{\sqrt{\pi}}\right)}
\end{array}
Initial program 98.0%
associate-+l+98.0%
associate-*l*98.0%
associate-*l/98.6%
*-lft-identity98.6%
Simplified98.6%
Taylor expanded in cosTheta around 0 95.8%
Final simplification95.8%
(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 98.0%
associate-*l*98.0%
*-lft-identity98.0%
associate-*r*98.0%
*-lft-identity98.0%
associate--l-98.0%
*-commutative98.0%
Simplified98.0%
associate-*l/98.6%
*-un-lft-identity98.6%
Applied egg-rr98.6%
Taylor expanded in cosTheta around 0 93.6%
Final simplification93.6%
(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 98.0%
Taylor expanded in c around 0 97.6%
Taylor expanded in cosTheta around inf 10.6%
Final simplification10.6%
herbie shell --seed 2023182
(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))))))