
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (PI))) (t_2 (* t_1 tau))) (* (/ (sin t_2) t_2) (/ (sin t_1) t_1))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := x \cdot \mathsf{PI}\left(\right)\\
t_2 := t\_1 \cdot tau\\
\frac{\sin t\_2}{t\_2} \cdot \frac{\sin t\_1}{t\_1}
\end{array}
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 10 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (PI))) (t_2 (* t_1 tau))) (* (/ (sin t_2) t_2) (/ (sin t_1) t_1))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := x \cdot \mathsf{PI}\left(\right)\\
t_2 := t\_1 \cdot tau\\
\frac{\sin t\_2}{t\_2} \cdot \frac{\sin t\_1}{t\_1}
\end{array}
\end{array}
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (PI))) (t_2 (* t_1 tau))) (/ (* (sin t_1) (/ (sin t_2) t_2)) t_1)))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := x \cdot \mathsf{PI}\left(\right)\\
t_2 := t\_1 \cdot tau\\
\frac{\sin t\_1 \cdot \frac{\sin t\_2}{t\_2}}{t\_1}
\end{array}
\end{array}
Initial program 98.0%
lift-*.f32N/A
lift-/.f32N/A
associate-*l/N/A
lower-/.f32N/A
Applied rewrites97.9%
lift-/.f32N/A
lift-*.f32N/A
associate-/l*N/A
lower-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
Applied rewrites97.9%
lift-*.f32N/A
lift-/.f32N/A
associate-*l/N/A
Applied rewrites98.0%
Final simplification98.0%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (PI))) (t_2 (* t_1 tau))) (* (/ (sin t_1) t_1) (/ (sin t_2) t_2))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := x \cdot \mathsf{PI}\left(\right)\\
t_2 := t\_1 \cdot tau\\
\frac{\sin t\_1}{t\_1} \cdot \frac{\sin t\_2}{t\_2}
\end{array}
\end{array}
Initial program 98.0%
Final simplification98.0%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (PI))) (t_2 (* t_1 tau))) (/ (* (sin t_1) (sin t_2)) (* t_2 t_1))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := x \cdot \mathsf{PI}\left(\right)\\
t_2 := t\_1 \cdot tau\\
\frac{\sin t\_1 \cdot \sin t\_2}{t\_2 \cdot t\_1}
\end{array}
\end{array}
Initial program 98.0%
lift-*.f32N/A
lift-/.f32N/A
associate-*l/N/A
lower-/.f32N/A
Applied rewrites97.9%
lift-/.f32N/A
lift-*.f32N/A
associate-/l*N/A
lower-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
Applied rewrites97.9%
lift-*.f32N/A
lift-/.f32N/A
associate-*l/N/A
Applied rewrites98.0%
lift-/.f32N/A
lift-*.f32N/A
associate-/l*N/A
lift-/.f32N/A
frac-2negN/A
frac-timesN/A
distribute-lft-neg-inN/A
*-commutativeN/A
lift-*.f32N/A
Applied rewrites98.0%
Final simplification98.0%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (PI))) (t_2 (* t_1 tau))) (/ (* (sin t_1) (sin t_2)) (* (* t_2 x) (PI)))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := x \cdot \mathsf{PI}\left(\right)\\
t_2 := t\_1 \cdot tau\\
\frac{\sin t\_1 \cdot \sin t\_2}{\left(t\_2 \cdot x\right) \cdot \mathsf{PI}\left(\right)}
\end{array}
\end{array}
Initial program 98.0%
lift-*.f32N/A
lift-/.f32N/A
associate-*l/N/A
lower-/.f32N/A
Applied rewrites97.9%
lift-/.f32N/A
lift-*.f32N/A
associate-/l*N/A
lower-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
Applied rewrites97.9%
lift-*.f32N/A
lift-/.f32N/A
associate-*l/N/A
Applied rewrites98.0%
Applied rewrites97.4%
Final simplification97.4%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (PI))) (t_2 (* t_1 tau))) (/ 1.0 (/ t_1 (* t_1 (/ (sin t_2) t_2))))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := x \cdot \mathsf{PI}\left(\right)\\
t_2 := t\_1 \cdot tau\\
\frac{1}{\frac{t\_1}{t\_1 \cdot \frac{\sin t\_2}{t\_2}}}
\end{array}
\end{array}
Initial program 98.0%
lift-*.f32N/A
lift-/.f32N/A
frac-2negN/A
associate-*r/N/A
lift-*.f32N/A
distribute-lft-neg-inN/A
times-fracN/A
lower-*.f32N/A
Applied rewrites97.6%
Taylor expanded in x around 0
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3271.8
Applied rewrites71.8%
lift-*.f32N/A
*-commutativeN/A
lift-/.f32N/A
frac-2negN/A
lift-neg.f32N/A
lift-/.f32N/A
frac-timesN/A
clear-numN/A
Applied rewrites72.0%
Final simplification72.0%
(FPCore (x tau)
:precision binary32
(let* ((t_1 (* (* x (PI)) tau)))
(*
(fma (* (* x x) -0.16666666666666666) (* (PI) (PI)) 1.0)
(/ (sin t_1) t_1))))\begin{array}{l}
\\
\begin{array}{l}
t_1 := \left(x \cdot \mathsf{PI}\left(\right)\right) \cdot tau\\
\mathsf{fma}\left(\left(x \cdot x\right) \cdot -0.16666666666666666, \mathsf{PI}\left(\right) \cdot \mathsf{PI}\left(\right), 1\right) \cdot \frac{\sin t\_1}{t\_1}
\end{array}
\end{array}
Initial program 98.0%
lift-/.f32N/A
clear-numN/A
associate-/r/N/A
lower-*.f32N/A
lower-/.f3297.8
lift-*.f32N/A
*-commutativeN/A
lower-*.f3297.8
lift-*.f32N/A
*-commutativeN/A
lower-*.f3297.8
Applied rewrites97.8%
Taylor expanded in x around 0
+-commutativeN/A
associate-*r*N/A
lower-fma.f32N/A
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
lower-PI.f32N/A
lower-PI.f3234.9
Applied rewrites35.9%
Final simplification31.4%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* (* x (PI)) tau))) (* (- x) (/ (/ (sin t_1) t_1) (- x)))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \left(x \cdot \mathsf{PI}\left(\right)\right) \cdot tau\\
\left(-x\right) \cdot \frac{\frac{\sin t\_1}{t\_1}}{-x}
\end{array}
\end{array}
Initial program 98.0%
lift-*.f32N/A
lift-/.f32N/A
frac-2negN/A
associate-*r/N/A
lift-*.f32N/A
distribute-lft-neg-inN/A
times-fracN/A
lower-*.f32N/A
Applied rewrites97.6%
Taylor expanded in x around 0
mul-1-negN/A
lower-neg.f3271.9
Applied rewrites71.9%
Final simplification71.9%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (PI)))) (* (/ 1.0 tau) (/ (sin (* t_1 tau)) t_1))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := x \cdot \mathsf{PI}\left(\right)\\
\frac{1}{tau} \cdot \frac{\sin \left(t\_1 \cdot tau\right)}{t\_1}
\end{array}
\end{array}
Initial program 98.0%
lift-*.f32N/A
lift-/.f32N/A
associate-*l/N/A
lower-/.f32N/A
Applied rewrites97.9%
lift-/.f32N/A
lift-*.f32N/A
associate-/l*N/A
lower-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
Applied rewrites97.9%
Taylor expanded in x around 0
lower-/.f3271.9
Applied rewrites71.9%
Final simplification71.9%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (PI)))) (/ (sin t_1) t_1)))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := x \cdot \mathsf{PI}\left(\right)\\
\frac{\sin t\_1}{t\_1}
\end{array}
\end{array}
Initial program 98.0%
lift-*.f32N/A
lift-/.f32N/A
associate-*l/N/A
lower-/.f32N/A
Applied rewrites97.9%
lift-/.f32N/A
lift-*.f32N/A
associate-/l*N/A
lower-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
Applied rewrites97.9%
Taylor expanded in tau around 0
lower-/.f32N/A
lower-sin.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3265.8
Applied rewrites65.8%
Final simplification65.8%
(FPCore (x tau) :precision binary32 1.0)
float code(float x, float tau) {
return 1.0f;
}
real(4) function code(x, tau)
real(4), intent (in) :: x
real(4), intent (in) :: tau
code = 1.0e0
end function
function code(x, tau) return Float32(1.0) end
function tmp = code(x, tau) tmp = single(1.0); end
\begin{array}{l}
\\
1
\end{array}
Initial program 98.0%
Taylor expanded in x around 0
Applied rewrites64.9%
herbie shell --seed 2024285
(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)))))