(FPCore (x tau) :precision binary32 (* (/ (sin (* (* x PI) tau)) (* (* x PI) tau)) (/ (sin (* x PI)) (* x PI))))
(FPCore (x tau)
:precision binary32
(let* ((t_1 (* PI (* x tau))) (t_2 (* x (* PI tau))))
(*
(* (cbrt (/ (sin t_2) t_2)) (cbrt (sqrt (pow (/ (sin t_1) t_1) 4.0))))
(/ (sin (* x PI)) (* x PI)))))float code(float x, float tau) {
return (sinf(((x * ((float) M_PI)) * tau)) / ((x * ((float) M_PI)) * tau)) * (sinf((x * ((float) M_PI))) / (x * ((float) M_PI)));
}
float code(float x, float tau) {
float t_1 = ((float) M_PI) * (x * tau);
float t_2 = x * (((float) M_PI) * tau);
return (cbrtf((sinf(t_2) / t_2)) * cbrtf(sqrtf(powf((sinf(t_1) / t_1), 4.0f)))) * (sinf((x * ((float) M_PI))) / (x * ((float) M_PI)));
}
function code(x, tau) return Float32(Float32(sin(Float32(Float32(x * Float32(pi)) * tau)) / Float32(Float32(x * Float32(pi)) * tau)) * Float32(sin(Float32(x * Float32(pi))) / Float32(x * Float32(pi)))) end
function code(x, tau) t_1 = Float32(Float32(pi) * Float32(x * tau)) t_2 = Float32(x * Float32(Float32(pi) * tau)) return Float32(Float32(cbrt(Float32(sin(t_2) / t_2)) * cbrt(sqrt((Float32(sin(t_1) / t_1) ^ Float32(4.0))))) * Float32(sin(Float32(x * Float32(pi))) / Float32(x * Float32(pi)))) end
\frac{\sin \left(\left(x \cdot \pi\right) \cdot tau\right)}{\left(x \cdot \pi\right) \cdot tau} \cdot \frac{\sin \left(x \cdot \pi\right)}{x \cdot \pi}
\begin{array}{l}
t_1 := \pi \cdot \left(x \cdot tau\right)\\
t_2 := x \cdot \left(\pi \cdot tau\right)\\
\left(\sqrt[3]{\frac{\sin t_2}{t_2}} \cdot \sqrt[3]{\sqrt{{\left(\frac{\sin t_1}{t_1}\right)}^{4}}}\right) \cdot \frac{\sin \left(x \cdot \pi\right)}{x \cdot \pi}
\end{array}
Results
Initial program 0.7
Applied egg-rr0.7
Applied egg-rr0.7
Final simplification0.7
herbie shell --seed 2022200
(FPCore (x tau)
:name "Lanczos kernel"
:precision binary32
:pre (and (and (<= 1e-5 x) (<= x 1.0)) (and (<= 1.0 tau) (<= tau 5.0)))
(* (/ (sin (* (* x PI) tau)) (* (* x PI) tau)) (/ (sin (* x PI)) (* x PI))))