
(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 7 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 (* (PI) x)) (t_2 (* tau t_1))) (/ (* (/ (sin t_1) t_1) (sin t_2)) t_2)))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \mathsf{PI}\left(\right) \cdot x\\
t_2 := tau \cdot t\_1\\
\frac{\frac{\sin t\_1}{t\_1} \cdot \sin t\_2}{t\_2}
\end{array}
\end{array}
Initial program 98.0%
lift-/.f32N/A
clear-numN/A
associate-/r/N/A
lower-*.f32N/A
lower-/.f3298.0
lift-*.f32N/A
*-commutativeN/A
lower-*.f3298.0
lift-*.f32N/A
*-commutativeN/A
lower-*.f3298.0
Applied rewrites98.0%
lift-*.f32N/A
lift-/.f32N/A
clear-numN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
div-invN/A
frac-timesN/A
Applied rewrites98.0%
Applied rewrites98.1%
(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}
Initial program 98.0%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (PI))) (t_2 (* tau t_1))) (/ (* (sin t_1) (sin t_2)) (* t_1 t_2))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := x \cdot \mathsf{PI}\left(\right)\\
t_2 := tau \cdot t\_1\\
\frac{\sin t\_1 \cdot \sin t\_2}{t\_1 \cdot t\_2}
\end{array}
\end{array}
Initial program 98.0%
lift-/.f32N/A
clear-numN/A
associate-/r/N/A
lower-*.f32N/A
lower-/.f3298.0
lift-*.f32N/A
*-commutativeN/A
lower-*.f3298.0
lift-*.f32N/A
*-commutativeN/A
lower-*.f3298.0
Applied rewrites98.0%
lift-*.f32N/A
lift-/.f32N/A
clear-numN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
div-invN/A
frac-timesN/A
Applied rewrites98.0%
Applied rewrites98.1%
lift-/.f32N/A
frac-2negN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
Applied rewrites97.8%
Final simplification97.8%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (PI))) (t_2 (* tau t_1))) (/ (* 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 := tau \cdot t\_1\\
\frac{t\_1 \cdot \frac{\sin t\_2}{t\_2}}{t\_1}
\end{array}
\end{array}
Initial program 98.0%
lift-/.f32N/A
clear-numN/A
associate-/r/N/A
lower-*.f32N/A
lower-/.f3298.0
lift-*.f32N/A
*-commutativeN/A
lower-*.f3298.0
lift-*.f32N/A
*-commutativeN/A
lower-*.f3298.0
Applied rewrites98.0%
lift-*.f32N/A
lift-/.f32N/A
clear-numN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
div-invN/A
frac-timesN/A
Applied rewrites97.6%
Taylor expanded in x around 0
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3270.9
Applied rewrites70.9%
lift-/.f32N/A
lift-/.f32N/A
clear-numN/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-/r*N/A
lower-/.f32N/A
Applied rewrites71.0%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* (* x (PI)) tau))) (* (/ (sin t_1) t_1) 1.0)))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \left(x \cdot \mathsf{PI}\left(\right)\right) \cdot tau\\
\frac{\sin t\_1}{t\_1} \cdot 1
\end{array}
\end{array}
Initial program 98.0%
lift-/.f32N/A
clear-numN/A
associate-/r/N/A
lower-*.f32N/A
lower-/.f3298.0
lift-*.f32N/A
*-commutativeN/A
lower-*.f3298.0
lift-*.f32N/A
*-commutativeN/A
lower-*.f3298.0
Applied rewrites98.0%
Taylor expanded in x around 0
Applied rewrites70.9%
(FPCore (x tau) :precision binary32 (+ (* (* x x) (* (* (PI) (PI)) -0.16666666666666666)) 1.0))
\begin{array}{l}
\\
\left(x \cdot x\right) \cdot \left(\left(\mathsf{PI}\left(\right) \cdot \mathsf{PI}\left(\right)\right) \cdot -0.16666666666666666\right) + 1
\end{array}
Initial program 98.0%
lift-/.f32N/A
clear-numN/A
associate-/r/N/A
lower-*.f32N/A
lower-/.f3298.0
lift-*.f32N/A
*-commutativeN/A
lower-*.f3298.0
lift-*.f32N/A
*-commutativeN/A
lower-*.f3298.0
Applied rewrites98.0%
Taylor expanded in x around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
Applied rewrites63.2%
Taylor expanded in tau around 0
Applied rewrites63.2%
Applied rewrites64.2%
(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 rewrites63.2%
Final simplification63.2%
herbie shell --seed 2024313
(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)))))