
(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 9 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 98.1%
frac-times98.6%
*-un-lft-identity98.6%
associate--r+98.6%
Applied egg-rr98.6%
Final simplification98.6%
(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 98.1%
associate-+l+98.1%
*-commutative98.1%
associate-*r*98.1%
*-commutative98.1%
associate-/r/98.0%
Simplified98.6%
Taylor expanded in c around 0 98.0%
Final simplification98.0%
(FPCore (cosTheta c) :precision binary32 (/ 1.0 (fma (/ (exp (* cosTheta (- cosTheta))) cosTheta) (sqrt (/ (+ 1.0 (* cosTheta -2.0)) PI)) 1.0)))
float code(float cosTheta, float c) {
return 1.0f / fmaf((expf((cosTheta * -cosTheta)) / cosTheta), sqrtf(((1.0f + (cosTheta * -2.0f)) / ((float) M_PI))), 1.0f);
}
function code(cosTheta, c) return Float32(Float32(1.0) / fma(Float32(exp(Float32(cosTheta * Float32(-cosTheta))) / cosTheta), sqrt(Float32(Float32(Float32(1.0) + Float32(cosTheta * Float32(-2.0))) / Float32(pi))), Float32(1.0))) end
\begin{array}{l}
\\
\frac{1}{\mathsf{fma}\left(\frac{e^{cosTheta \cdot \left(-cosTheta\right)}}{cosTheta}, \sqrt{\frac{1 + cosTheta \cdot -2}{\pi}}, 1\right)}
\end{array}
Initial program 98.1%
frac-times98.6%
*-un-lft-identity98.6%
associate--r+98.6%
Applied egg-rr98.6%
Taylor expanded in c around 0 98.0%
fma-def98.0%
mul-1-neg98.0%
unpow298.0%
distribute-rgt-neg-out98.0%
cancel-sign-sub-inv98.0%
metadata-eval98.0%
Simplified98.0%
Final simplification98.0%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
1.0
(/
(sqrt (/ (+ 1.0 (* cosTheta -2.0)) PI))
(* cosTheta (exp (* cosTheta cosTheta)))))))
float code(float cosTheta, float c) {
return 1.0f / (1.0f + (sqrtf(((1.0f + (cosTheta * -2.0f)) / ((float) M_PI))) / (cosTheta * expf((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(cosTheta * exp(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))) / (cosTheta * exp((cosTheta * cosTheta))))); end
\begin{array}{l}
\\
\frac{1}{1 + \frac{\sqrt{\frac{1 + cosTheta \cdot -2}{\pi}}}{cosTheta \cdot e^{cosTheta \cdot cosTheta}}}
\end{array}
Initial program 98.1%
associate-+l+98.1%
*-commutative98.1%
associate-*r*98.1%
*-commutative98.1%
associate-/r/98.0%
Simplified98.6%
Taylor expanded in c around 0 98.0%
un-div-inv98.0%
*-commutative98.0%
unpow298.0%
Applied egg-rr98.0%
Final simplification98.0%
(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 98.1%
associate-+l+98.1%
*-commutative98.1%
associate-*r*98.1%
*-commutative98.1%
associate-/r/98.0%
Simplified98.6%
Taylor expanded in c around 0 98.0%
Taylor expanded in cosTheta around 0 95.6%
distribute-rgt-out95.6%
Simplified95.6%
Final simplification95.6%
(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 98.1%
frac-times98.6%
*-un-lft-identity98.6%
associate--r+98.6%
Applied egg-rr98.6%
Taylor expanded in cosTheta around 0 93.2%
Final simplification93.2%
(FPCore (cosTheta c) :precision binary32 (* (- c) (* PI (* cosTheta cosTheta))))
float code(float cosTheta, float c) {
return -c * (((float) M_PI) * (cosTheta * cosTheta));
}
function code(cosTheta, c) return Float32(Float32(-c) * Float32(Float32(pi) * Float32(cosTheta * cosTheta))) end
function tmp = code(cosTheta, c) tmp = -c * (single(pi) * (cosTheta * cosTheta)); end
\begin{array}{l}
\\
\left(-c\right) \cdot \left(\pi \cdot \left(cosTheta \cdot cosTheta\right)\right)
\end{array}
Initial program 98.1%
associate-+l+98.1%
*-commutative98.1%
associate-*r*98.1%
*-commutative98.1%
associate-/r/98.0%
Simplified98.6%
Taylor expanded in cosTheta around 0 92.9%
Taylor expanded in cosTheta around 0 92.9%
fma-def93.0%
associate-*r*93.0%
*-commutative93.0%
unpow293.0%
+-commutative93.0%
distribute-lft-in93.0%
metadata-eval93.0%
mul-1-neg93.0%
unsub-neg93.0%
Simplified93.0%
Taylor expanded in c around inf 11.0%
associate-*r*11.0%
mul-1-neg11.0%
*-commutative11.0%
unpow211.0%
Simplified11.0%
Final simplification11.0%
(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 98.1%
associate-+l+98.1%
*-commutative98.1%
associate-*r*98.1%
*-commutative98.1%
associate-/r/98.0%
Simplified98.6%
Taylor expanded in cosTheta around inf 10.4%
Taylor expanded in c around 0 10.4%
+-commutative10.4%
mul-1-neg10.4%
unsub-neg10.4%
Simplified10.4%
Final simplification10.4%
(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 98.1%
associate-+l+98.1%
*-commutative98.1%
associate-*r*98.1%
*-commutative98.1%
associate-/r/98.0%
Simplified98.6%
Taylor expanded in cosTheta around inf 10.4%
Taylor expanded in c around 0 10.4%
Final simplification10.4%
herbie shell --seed 2023278
(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))))))