
(FPCore (ux uy maxCos) :precision binary32 (let* ((t_0 (+ (- 1.0 ux) (* ux maxCos)))) (* (sin (* (* uy 2.0) PI)) (sqrt (- 1.0 (* t_0 t_0))))))
float code(float ux, float uy, float maxCos) {
float t_0 = (1.0f - ux) + (ux * maxCos);
return sinf(((uy * 2.0f) * ((float) M_PI))) * sqrtf((1.0f - (t_0 * t_0)));
}
function code(ux, uy, maxCos) t_0 = Float32(Float32(Float32(1.0) - ux) + Float32(ux * maxCos)) return Float32(sin(Float32(Float32(uy * Float32(2.0)) * Float32(pi))) * sqrt(Float32(Float32(1.0) - Float32(t_0 * t_0)))) end
function tmp = code(ux, uy, maxCos) t_0 = (single(1.0) - ux) + (ux * maxCos); tmp = sin(((uy * single(2.0)) * single(pi))) * sqrt((single(1.0) - (t_0 * t_0))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(1 - ux\right) + ux \cdot maxCos\\
\sin \left(\left(uy \cdot 2\right) \cdot \pi\right) \cdot \sqrt{1 - t\_0 \cdot t\_0}
\end{array}
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 14 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (ux uy maxCos) :precision binary32 (let* ((t_0 (+ (- 1.0 ux) (* ux maxCos)))) (* (sin (* (* uy 2.0) PI)) (sqrt (- 1.0 (* t_0 t_0))))))
float code(float ux, float uy, float maxCos) {
float t_0 = (1.0f - ux) + (ux * maxCos);
return sinf(((uy * 2.0f) * ((float) M_PI))) * sqrtf((1.0f - (t_0 * t_0)));
}
function code(ux, uy, maxCos) t_0 = Float32(Float32(Float32(1.0) - ux) + Float32(ux * maxCos)) return Float32(sin(Float32(Float32(uy * Float32(2.0)) * Float32(pi))) * sqrt(Float32(Float32(1.0) - Float32(t_0 * t_0)))) end
function tmp = code(ux, uy, maxCos) t_0 = (single(1.0) - ux) + (ux * maxCos); tmp = sin(((uy * single(2.0)) * single(pi))) * sqrt((single(1.0) - (t_0 * t_0))); end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(1 - ux\right) + ux \cdot maxCos\\
\sin \left(\left(uy \cdot 2\right) \cdot \pi\right) \cdot \sqrt{1 - t\_0 \cdot t\_0}
\end{array}
\end{array}
(FPCore (ux uy maxCos)
:precision binary32
(let* ((t_0
(fma
(+ maxCos -1.0)
(* ux (- 1.0 maxCos))
(- (fma maxCos -2.0 2.0)))))
(*
(sin (* (* uy 2.0) PI))
(sqrt
(/
(*
ux
(*
(fma ux (* (+ maxCos -1.0) (- 1.0 maxCos)) (fma maxCos -2.0 2.0))
t_0))
t_0)))))
float code(float ux, float uy, float maxCos) {
float t_0 = fmaf((maxCos + -1.0f), (ux * (1.0f - maxCos)), -fmaf(maxCos, -2.0f, 2.0f));
return sinf(((uy * 2.0f) * ((float) M_PI))) * sqrtf(((ux * (fmaf(ux, ((maxCos + -1.0f) * (1.0f - maxCos)), fmaf(maxCos, -2.0f, 2.0f)) * t_0)) / t_0));
}
function code(ux, uy, maxCos) t_0 = fma(Float32(maxCos + Float32(-1.0)), Float32(ux * Float32(Float32(1.0) - maxCos)), Float32(-fma(maxCos, Float32(-2.0), Float32(2.0)))) return Float32(sin(Float32(Float32(uy * Float32(2.0)) * Float32(pi))) * sqrt(Float32(Float32(ux * Float32(fma(ux, Float32(Float32(maxCos + Float32(-1.0)) * Float32(Float32(1.0) - maxCos)), fma(maxCos, Float32(-2.0), Float32(2.0))) * t_0)) / t_0))) end
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \mathsf{fma}\left(maxCos + -1, ux \cdot \left(1 - maxCos\right), -\mathsf{fma}\left(maxCos, -2, 2\right)\right)\\
\sin \left(\left(uy \cdot 2\right) \cdot \pi\right) \cdot \sqrt{\frac{ux \cdot \left(\mathsf{fma}\left(ux, \left(maxCos + -1\right) \cdot \left(1 - maxCos\right), \mathsf{fma}\left(maxCos, -2, 2\right)\right) \cdot t\_0\right)}{t\_0}}
\end{array}
\end{array}
Initial program 56.9%
Taylor expanded in ux around 0
lower-*.f32N/A
cancel-sign-sub-invN/A
+-commutativeN/A
metadata-evalN/A
associate-+l+N/A
mul-1-negN/A
distribute-rgt-neg-inN/A
lower-fma.f32N/A
Applied rewrites98.3%
Applied rewrites98.4%
Final simplification98.4%
(FPCore (ux uy maxCos)
:precision binary32
(if (<=
(*
(sin (* (* uy 2.0) PI))
(sqrt
(+
1.0
(* (+ (- 1.0 ux) (* ux maxCos)) (- (+ ux -1.0) (* ux maxCos))))))
0.00014000000373926014)
(*
2.0
(*
(* uy PI)
(sqrt
(*
ux
(+ 2.0 (fma ux (* (+ maxCos -1.0) (- 1.0 maxCos)) (* maxCos -2.0)))))))
(*
(sqrt
(fma (fma ux maxCos (- 1.0 ux)) (fma (- ux) (+ maxCos -1.0) -1.0) 1.0))
(* uy (* PI (fma (* -1.3333333333333333 (* uy uy)) (* PI PI) 2.0))))))
float code(float ux, float uy, float maxCos) {
float tmp;
if ((sinf(((uy * 2.0f) * ((float) M_PI))) * sqrtf((1.0f + (((1.0f - ux) + (ux * maxCos)) * ((ux + -1.0f) - (ux * maxCos)))))) <= 0.00014000000373926014f) {
tmp = 2.0f * ((uy * ((float) M_PI)) * sqrtf((ux * (2.0f + fmaf(ux, ((maxCos + -1.0f) * (1.0f - maxCos)), (maxCos * -2.0f))))));
} else {
tmp = sqrtf(fmaf(fmaf(ux, maxCos, (1.0f - ux)), fmaf(-ux, (maxCos + -1.0f), -1.0f), 1.0f)) * (uy * (((float) M_PI) * fmaf((-1.3333333333333333f * (uy * uy)), (((float) M_PI) * ((float) M_PI)), 2.0f)));
}
return tmp;
}
function code(ux, uy, maxCos) tmp = Float32(0.0) if (Float32(sin(Float32(Float32(uy * Float32(2.0)) * Float32(pi))) * sqrt(Float32(Float32(1.0) + Float32(Float32(Float32(Float32(1.0) - ux) + Float32(ux * maxCos)) * Float32(Float32(ux + Float32(-1.0)) - Float32(ux * maxCos)))))) <= Float32(0.00014000000373926014)) tmp = Float32(Float32(2.0) * Float32(Float32(uy * Float32(pi)) * sqrt(Float32(ux * Float32(Float32(2.0) + fma(ux, Float32(Float32(maxCos + Float32(-1.0)) * Float32(Float32(1.0) - maxCos)), Float32(maxCos * Float32(-2.0)))))))); else tmp = Float32(sqrt(fma(fma(ux, maxCos, Float32(Float32(1.0) - ux)), fma(Float32(-ux), Float32(maxCos + Float32(-1.0)), Float32(-1.0)), Float32(1.0))) * Float32(uy * Float32(Float32(pi) * fma(Float32(Float32(-1.3333333333333333) * Float32(uy * uy)), Float32(Float32(pi) * Float32(pi)), Float32(2.0))))); end return tmp end
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\sin \left(\left(uy \cdot 2\right) \cdot \pi\right) \cdot \sqrt{1 + \left(\left(1 - ux\right) + ux \cdot maxCos\right) \cdot \left(\left(ux + -1\right) - ux \cdot maxCos\right)} \leq 0.00014000000373926014:\\
\;\;\;\;2 \cdot \left(\left(uy \cdot \pi\right) \cdot \sqrt{ux \cdot \left(2 + \mathsf{fma}\left(ux, \left(maxCos + -1\right) \cdot \left(1 - maxCos\right), maxCos \cdot -2\right)\right)}\right)\\
\mathbf{else}:\\
\;\;\;\;\sqrt{\mathsf{fma}\left(\mathsf{fma}\left(ux, maxCos, 1 - ux\right), \mathsf{fma}\left(-ux, maxCos + -1, -1\right), 1\right)} \cdot \left(uy \cdot \left(\pi \cdot \mathsf{fma}\left(-1.3333333333333333 \cdot \left(uy \cdot uy\right), \pi \cdot \pi, 2\right)\right)\right)\\
\end{array}
\end{array}
if (*.f32 (sin.f32 (*.f32 (*.f32 uy #s(literal 2 binary32)) (PI.f32))) (sqrt.f32 (-.f32 #s(literal 1 binary32) (*.f32 (+.f32 (-.f32 #s(literal 1 binary32) ux) (*.f32 ux maxCos)) (+.f32 (-.f32 #s(literal 1 binary32) ux) (*.f32 ux maxCos)))))) < 1.40000004e-4Initial program 51.3%
Taylor expanded in uy around 0
lower-*.f32N/A
lower-*.f32N/A
lower-*.f32N/A
lower-PI.f32N/A
lower-sqrt.f32N/A
sub-negN/A
+-commutativeN/A
unpow2N/A
distribute-rgt-neg-inN/A
lower-fma.f32N/A
Applied rewrites49.5%
Applied rewrites57.7%
Taylor expanded in ux around 0
Applied rewrites88.6%
if 1.40000004e-4 < (*.f32 (sin.f32 (*.f32 (*.f32 uy #s(literal 2 binary32)) (PI.f32))) (sqrt.f32 (-.f32 #s(literal 1 binary32) (*.f32 (+.f32 (-.f32 #s(literal 1 binary32) ux) (*.f32 ux maxCos)) (+.f32 (-.f32 #s(literal 1 binary32) ux) (*.f32 ux maxCos)))))) Initial program 79.5%
Taylor expanded in uy around 0
Applied rewrites67.2%
Final simplification84.0%
herbie shell --seed 2024229
(FPCore (ux uy maxCos)
:name "UniformSampleCone, y"
:precision binary32
:pre (and (and (and (<= 2.328306437e-10 ux) (<= ux 1.0)) (and (<= 2.328306437e-10 uy) (<= uy 1.0))) (and (<= 0.0 maxCos) (<= maxCos 1.0)))
(* (sin (* (* uy 2.0) PI)) (sqrt (- 1.0 (* (+ (- 1.0 ux) (* ux maxCos)) (+ (- 1.0 ux) (* ux maxCos)))))))