
(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 8 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 (fma -2.0 cosTheta 1.0)) cosTheta) (sqrt PI))
(- (cosh (* cosTheta cosTheta)) (sinh (* cosTheta cosTheta)))))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + (((sqrtf(fmaf(-2.0f, cosTheta, 1.0f)) / cosTheta) / sqrtf(((float) M_PI))) * (coshf((cosTheta * cosTheta)) - sinhf((cosTheta * cosTheta)))));
}
function code(cosTheta, c) return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(Float32(Float32(sqrt(fma(Float32(-2.0), cosTheta, Float32(1.0))) / cosTheta) / sqrt(Float32(pi))) * Float32(cosh(Float32(cosTheta * cosTheta)) - sinh(Float32(cosTheta * cosTheta)))))) end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + \frac{\frac{\sqrt{\mathsf{fma}\left(-2, cosTheta, 1\right)}}{cosTheta}}{\sqrt{\pi}} \cdot \left(\cosh \left(cosTheta \cdot cosTheta\right) - \sinh \left(cosTheta \cdot cosTheta\right)\right)}
\end{array}
Initial program 97.8%
lift-*.f32N/A
lift-/.f32N/A
lift-PI.f32N/A
lift-sqrt.f32N/A
lift-/.f32N/A
lift-sqrt.f32N/A
lift--.f32N/A
lift--.f32N/A
associate-*l/N/A
lower-/.f32N/A
Applied rewrites98.1%
lift-exp.f32N/A
lift-neg.f32N/A
lift-*.f32N/A
sinh-+-cosh-revN/A
lower-+.f32N/A
lower-cosh.f32N/A
lift-*.f32N/A
lift-neg.f32N/A
lower-sinh.f32N/A
lift-*.f32N/A
lift-neg.f3298.1
Applied rewrites98.1%
Final simplification98.1%
(FPCore (cosTheta c)
:precision binary32
(/
1.0
(+
(+ 1.0 c)
(*
(/ (/ (sqrt (fma -2.0 cosTheta 1.0)) cosTheta) (sqrt PI))
(exp (* (- cosTheta) cosTheta))))))
float code(float cosTheta, float c) {
return 1.0f / ((1.0f + c) + (((sqrtf(fmaf(-2.0f, cosTheta, 1.0f)) / 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(Float32(sqrt(fma(Float32(-2.0), cosTheta, Float32(1.0))) / cosTheta) / sqrt(Float32(pi))) * exp(Float32(Float32(-cosTheta) * cosTheta))))) end
\begin{array}{l}
\\
\frac{1}{\left(1 + c\right) + \frac{\frac{\sqrt{\mathsf{fma}\left(-2, cosTheta, 1\right)}}{cosTheta}}{\sqrt{\pi}} \cdot e^{\left(-cosTheta\right) \cdot cosTheta}}
\end{array}
Initial program 97.8%
lift-*.f32N/A
lift-/.f32N/A
lift-PI.f32N/A
lift-sqrt.f32N/A
lift-/.f32N/A
lift-sqrt.f32N/A
lift--.f32N/A
lift--.f32N/A
associate-*l/N/A
lower-/.f32N/A
Applied rewrites98.1%
Final simplification98.1%
(FPCore (cosTheta c)
:precision binary32
(let* ((t_0 (/ (exp (* (- cosTheta) cosTheta)) cosTheta))
(t_1 (fma (sqrt (/ (fma -2.0 cosTheta 1.0) PI)) t_0 1.0)))
(fma
(- (/ c (pow t_1 3.0)) (pow t_1 -2.0))
c
(/
1.0
(fma
(sqrt (* cosTheta (- (/ 1.0 (* cosTheta PI)) (* 2.0 (/ 1.0 PI)))))
t_0
1.0)))))
float code(float cosTheta, float c) {
float t_0 = expf((-cosTheta * cosTheta)) / cosTheta;
float t_1 = fmaf(sqrtf((fmaf(-2.0f, cosTheta, 1.0f) / ((float) M_PI))), t_0, 1.0f);
return fmaf(((c / powf(t_1, 3.0f)) - powf(t_1, -2.0f)), c, (1.0f / fmaf(sqrtf((cosTheta * ((1.0f / (cosTheta * ((float) M_PI))) - (2.0f * (1.0f / ((float) M_PI)))))), t_0, 1.0f)));
}
function code(cosTheta, c) t_0 = Float32(exp(Float32(Float32(-cosTheta) * cosTheta)) / cosTheta) t_1 = fma(sqrt(Float32(fma(Float32(-2.0), cosTheta, Float32(1.0)) / Float32(pi))), t_0, Float32(1.0)) return fma(Float32(Float32(c / (t_1 ^ Float32(3.0))) - (t_1 ^ Float32(-2.0))), c, Float32(Float32(1.0) / fma(sqrt(Float32(cosTheta * Float32(Float32(Float32(1.0) / Float32(cosTheta * Float32(pi))) - Float32(Float32(2.0) * Float32(Float32(1.0) / Float32(pi)))))), t_0, Float32(1.0)))) end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{e^{\left(-cosTheta\right) \cdot cosTheta}}{cosTheta}\\
t_1 := \mathsf{fma}\left(\sqrt{\frac{\mathsf{fma}\left(-2, cosTheta, 1\right)}{\pi}}, t\_0, 1\right)\\
\mathsf{fma}\left(\frac{c}{{t\_1}^{3}} - {t\_1}^{-2}, c, \frac{1}{\mathsf{fma}\left(\sqrt{cosTheta \cdot \left(\frac{1}{cosTheta \cdot \pi} - 2 \cdot \frac{1}{\pi}\right)}, t\_0, 1\right)}\right)
\end{array}
\end{array}
Initial program 97.8%
Taylor expanded in c around 0
*-commutativeN/A
Applied rewrites97.8%
Taylor expanded in cosTheta around inf
lower-*.f32N/A
lower--.f32N/A
lower-/.f32N/A
lower-*.f32N/A
lift-PI.f32N/A
lower-*.f32N/A
lower-/.f32N/A
lift-PI.f3297.8
Applied rewrites97.8%
(FPCore (cosTheta c)
:precision binary32
(let* ((t_0
(fma
(sqrt (/ (fma -2.0 cosTheta 1.0) PI))
(/ (exp (* (- cosTheta) cosTheta)) cosTheta)
1.0)))
(fma
(- (/ c (pow t_0 3.0)) (pow (* (/ 1.0 cosTheta) (/ 1.0 (sqrt PI))) -2.0))
c
(/ 1.0 t_0))))
float code(float cosTheta, float c) {
float t_0 = fmaf(sqrtf((fmaf(-2.0f, cosTheta, 1.0f) / ((float) M_PI))), (expf((-cosTheta * cosTheta)) / cosTheta), 1.0f);
return fmaf(((c / powf(t_0, 3.0f)) - powf(((1.0f / cosTheta) * (1.0f / sqrtf(((float) M_PI)))), -2.0f)), c, (1.0f / t_0));
}
function code(cosTheta, c) t_0 = fma(sqrt(Float32(fma(Float32(-2.0), cosTheta, Float32(1.0)) / Float32(pi))), Float32(exp(Float32(Float32(-cosTheta) * cosTheta)) / cosTheta), Float32(1.0)) return fma(Float32(Float32(c / (t_0 ^ Float32(3.0))) - (Float32(Float32(Float32(1.0) / cosTheta) * Float32(Float32(1.0) / sqrt(Float32(pi)))) ^ Float32(-2.0))), c, Float32(Float32(1.0) / t_0)) end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \mathsf{fma}\left(\sqrt{\frac{\mathsf{fma}\left(-2, cosTheta, 1\right)}{\pi}}, \frac{e^{\left(-cosTheta\right) \cdot cosTheta}}{cosTheta}, 1\right)\\
\mathsf{fma}\left(\frac{c}{{t\_0}^{3}} - {\left(\frac{1}{cosTheta} \cdot \frac{1}{\sqrt{\pi}}\right)}^{-2}, c, \frac{1}{t\_0}\right)
\end{array}
\end{array}
Initial program 97.8%
Taylor expanded in c around 0
*-commutativeN/A
Applied rewrites97.8%
Taylor expanded in cosTheta around 0
lower-*.f32N/A
lower-/.f32N/A
sqrt-divN/A
metadata-evalN/A
lift-sqrt.f32N/A
lift-PI.f32N/A
lift-/.f3297.5
Applied rewrites97.5%
(FPCore (cosTheta c) :precision binary32 (* (fma (- cosTheta) (* (+ (fma (/ 1.0 (sqrt PI)) -1.0 c) 1.0) PI) (sqrt PI)) cosTheta))
float code(float cosTheta, float c) {
return fmaf(-cosTheta, ((fmaf((1.0f / sqrtf(((float) M_PI))), -1.0f, c) + 1.0f) * ((float) M_PI)), sqrtf(((float) M_PI))) * cosTheta;
}
function code(cosTheta, c) return Float32(fma(Float32(-cosTheta), Float32(Float32(fma(Float32(Float32(1.0) / sqrt(Float32(pi))), Float32(-1.0), c) + Float32(1.0)) * Float32(pi)), sqrt(Float32(pi))) * cosTheta) end
\begin{array}{l}
\\
\mathsf{fma}\left(-cosTheta, \left(\mathsf{fma}\left(\frac{1}{\sqrt{\pi}}, -1, c\right) + 1\right) \cdot \pi, \sqrt{\pi}\right) \cdot cosTheta
\end{array}
Initial program 97.8%
Taylor expanded in cosTheta around 0
*-commutativeN/A
lower-*.f32N/A
Applied rewrites96.1%
(FPCore (cosTheta c)
:precision binary32
(*
(*
(- c)
(fma
-1.0
(/ (- (sqrt PI) (* cosTheta (* PI (- 1.0 (/ 1.0 (sqrt PI)))))) c)
(* cosTheta PI)))
cosTheta))
float code(float cosTheta, float c) {
return (-c * fmaf(-1.0f, ((sqrtf(((float) M_PI)) - (cosTheta * (((float) M_PI) * (1.0f - (1.0f / sqrtf(((float) M_PI))))))) / c), (cosTheta * ((float) M_PI)))) * cosTheta;
}
function code(cosTheta, c) return Float32(Float32(Float32(-c) * fma(Float32(-1.0), Float32(Float32(sqrt(Float32(pi)) - Float32(cosTheta * Float32(Float32(pi) * Float32(Float32(1.0) - Float32(Float32(1.0) / sqrt(Float32(pi))))))) / c), Float32(cosTheta * Float32(pi)))) * cosTheta) end
\begin{array}{l}
\\
\left(\left(-c\right) \cdot \mathsf{fma}\left(-1, \frac{\sqrt{\pi} - cosTheta \cdot \left(\pi \cdot \left(1 - \frac{1}{\sqrt{\pi}}\right)\right)}{c}, cosTheta \cdot \pi\right)\right) \cdot cosTheta
\end{array}
Initial program 97.8%
Taylor expanded in cosTheta around 0
*-commutativeN/A
lower-*.f32N/A
Applied rewrites96.1%
Taylor expanded in c around -inf
lower-*.f32N/A
lower-*.f32N/A
lower-fma.f32N/A
Applied rewrites95.8%
Final simplification95.8%
(FPCore (cosTheta c)
:precision binary32
(let* ((t_0
(+
1.0
(*
(/ (pow (exp -1.0) (* cosTheta cosTheta)) cosTheta)
(sqrt (/ (+ 1.0 (* -2.0 cosTheta)) PI))))))
(if (or (<= c -5.000000156871975e-23) (not (<= c 1.9999999996399175e-23)))
(*
(* c c)
(-
(+ (/ 1.0 (* (* c c) t_0)) (pow t_0 -3.0))
(/ 1.0 (* c (pow t_0 2.0)))))
(*
(* cosTheta cosTheta)
(/
(- (sqrt PI) (* cosTheta (* PI (+ 1.0 (- c (/ 1.0 (sqrt PI)))))))
cosTheta)))))
float code(float cosTheta, float c) {
float t_0 = 1.0f + ((powf(expf(-1.0f), (cosTheta * cosTheta)) / cosTheta) * sqrtf(((1.0f + (-2.0f * cosTheta)) / ((float) M_PI))));
float tmp;
if ((c <= -5.000000156871975e-23f) || !(c <= 1.9999999996399175e-23f)) {
tmp = (c * c) * (((1.0f / ((c * c) * t_0)) + powf(t_0, -3.0f)) - (1.0f / (c * powf(t_0, 2.0f))));
} else {
tmp = (cosTheta * cosTheta) * ((sqrtf(((float) M_PI)) - (cosTheta * (((float) M_PI) * (1.0f + (c - (1.0f / sqrtf(((float) M_PI)))))))) / cosTheta);
}
return tmp;
}
function code(cosTheta, c) t_0 = Float32(Float32(1.0) + Float32(Float32((exp(Float32(-1.0)) ^ Float32(cosTheta * cosTheta)) / cosTheta) * sqrt(Float32(Float32(Float32(1.0) + Float32(Float32(-2.0) * cosTheta)) / Float32(pi))))) tmp = Float32(0.0) if ((c <= Float32(-5.000000156871975e-23)) || !(c <= Float32(1.9999999996399175e-23))) tmp = Float32(Float32(c * c) * Float32(Float32(Float32(Float32(1.0) / Float32(Float32(c * c) * t_0)) + (t_0 ^ Float32(-3.0))) - Float32(Float32(1.0) / Float32(c * (t_0 ^ Float32(2.0)))))); else tmp = Float32(Float32(cosTheta * cosTheta) * Float32(Float32(sqrt(Float32(pi)) - Float32(cosTheta * Float32(Float32(pi) * Float32(Float32(1.0) + Float32(c - Float32(Float32(1.0) / sqrt(Float32(pi)))))))) / cosTheta)); end return tmp end
function tmp_2 = code(cosTheta, c) t_0 = single(1.0) + (((exp(single(-1.0)) ^ (cosTheta * cosTheta)) / cosTheta) * sqrt(((single(1.0) + (single(-2.0) * cosTheta)) / single(pi)))); tmp = single(0.0); if ((c <= single(-5.000000156871975e-23)) || ~((c <= single(1.9999999996399175e-23)))) tmp = (c * c) * (((single(1.0) / ((c * c) * t_0)) + (t_0 ^ single(-3.0))) - (single(1.0) / (c * (t_0 ^ single(2.0))))); else tmp = (cosTheta * cosTheta) * ((sqrt(single(pi)) - (cosTheta * (single(pi) * (single(1.0) + (c - (single(1.0) / sqrt(single(pi)))))))) / cosTheta); end tmp_2 = tmp; end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := 1 + \frac{{\left(e^{-1}\right)}^{\left(cosTheta \cdot cosTheta\right)}}{cosTheta} \cdot \sqrt{\frac{1 + -2 \cdot cosTheta}{\pi}}\\
\mathbf{if}\;c \leq -5.000000156871975 \cdot 10^{-23} \lor \neg \left(c \leq 1.9999999996399175 \cdot 10^{-23}\right):\\
\;\;\;\;\left(c \cdot c\right) \cdot \left(\left(\frac{1}{\left(c \cdot c\right) \cdot t\_0} + {t\_0}^{-3}\right) - \frac{1}{c \cdot {t\_0}^{2}}\right)\\
\mathbf{else}:\\
\;\;\;\;\left(cosTheta \cdot cosTheta\right) \cdot \frac{\sqrt{\pi} - cosTheta \cdot \left(\pi \cdot \left(1 + \left(c - \frac{1}{\sqrt{\pi}}\right)\right)\right)}{cosTheta}\\
\end{array}
\end{array}
if c < -5.00000016e-23 or 2e-23 < c Initial program 98.0%
Taylor expanded in c around 0
*-commutativeN/A
Applied rewrites97.8%
Taylor expanded in c around inf
Applied rewrites97.2%
if -5.00000016e-23 < c < 2e-23Initial program 97.5%
Taylor expanded in cosTheta around 0
*-commutativeN/A
lower-*.f32N/A
Applied rewrites97.3%
Taylor expanded in cosTheta around inf
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
lower-fma.f32N/A
Applied rewrites49.2%
Taylor expanded in cosTheta around 0
lower-/.f32N/A
Applied rewrites49.3%
Final simplification77.2%
(FPCore (cosTheta c) :precision binary32 (* (* cosTheta cosTheta) (/ (- (sqrt PI) (* cosTheta (* PI (+ 1.0 (- c (/ 1.0 (sqrt PI))))))) cosTheta)))
float code(float cosTheta, float c) {
return (cosTheta * cosTheta) * ((sqrtf(((float) M_PI)) - (cosTheta * (((float) M_PI) * (1.0f + (c - (1.0f / sqrtf(((float) M_PI)))))))) / cosTheta);
}
function code(cosTheta, c) return Float32(Float32(cosTheta * cosTheta) * Float32(Float32(sqrt(Float32(pi)) - Float32(cosTheta * Float32(Float32(pi) * Float32(Float32(1.0) + Float32(c - Float32(Float32(1.0) / sqrt(Float32(pi)))))))) / cosTheta)) end
function tmp = code(cosTheta, c) tmp = (cosTheta * cosTheta) * ((sqrt(single(pi)) - (cosTheta * (single(pi) * (single(1.0) + (c - (single(1.0) / sqrt(single(pi)))))))) / cosTheta); end
\begin{array}{l}
\\
\left(cosTheta \cdot cosTheta\right) \cdot \frac{\sqrt{\pi} - cosTheta \cdot \left(\pi \cdot \left(1 + \left(c - \frac{1}{\sqrt{\pi}}\right)\right)\right)}{cosTheta}
\end{array}
Initial program 97.8%
Taylor expanded in cosTheta around 0
*-commutativeN/A
lower-*.f32N/A
Applied rewrites96.1%
Taylor expanded in cosTheta around inf
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
lower-fma.f32N/A
Applied rewrites54.8%
Taylor expanded in cosTheta around 0
lower-/.f32N/A
Applied rewrites54.9%
Final simplification54.9%
herbie shell --seed 2025057
(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))))))