
(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 8 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 (* x (* tau (PI))))) (* (/ (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 := x \cdot \left(tau \cdot \mathsf{PI}\left(\right)\right)\\
\frac{\sin t\_1}{t\_1} \cdot \frac{\sin t\_2}{t\_2}
\end{array}
\end{array}
Initial program 97.8%
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f3297.2
Applied rewrites97.2%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
associate-*r*N/A
lift-*.f32N/A
lift-*.f3297.8
lift-*.f32N/A
*-commutativeN/A
lower-*.f3297.8
Applied rewrites97.8%
Final simplification97.8%
(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 97.8%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (PI))) (t_2 (* x (* tau (PI))))) (/ (* (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 := x \cdot \left(tau \cdot \mathsf{PI}\left(\right)\right)\\
\frac{\sin t\_1 \cdot \sin t\_2}{t\_1 \cdot t\_2}
\end{array}
\end{array}
Initial program 97.8%
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f3297.2
Applied rewrites97.2%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
associate-*r*N/A
lift-*.f32N/A
lift-*.f3297.8
lift-*.f32N/A
*-commutativeN/A
lower-*.f3297.8
Applied rewrites97.8%
Applied rewrites97.7%
lift-/.f32N/A
lift-*.f32N/A
associate-/l*N/A
lift-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
associate-*l*N/A
lift-*.f32N/A
lift-*.f32N/A
frac-timesN/A
Applied rewrites97.7%
Final simplification97.7%
(FPCore (x tau) :precision binary32 (/ (* (sin (* x (PI))) (sin (* x (* tau (PI))))) (* (* (* (* x x) (PI)) tau) (PI))))
\begin{array}{l}
\\
\frac{\sin \left(x \cdot \mathsf{PI}\left(\right)\right) \cdot \sin \left(x \cdot \left(tau \cdot \mathsf{PI}\left(\right)\right)\right)}{\left(\left(\left(x \cdot x\right) \cdot \mathsf{PI}\left(\right)\right) \cdot tau\right) \cdot \mathsf{PI}\left(\right)}
\end{array}
Initial program 97.8%
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f3297.2
Applied rewrites97.2%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
associate-*r*N/A
lift-*.f32N/A
lift-*.f3297.8
lift-*.f32N/A
*-commutativeN/A
lower-*.f3297.8
Applied rewrites97.8%
Applied rewrites97.7%
lift-/.f32N/A
lift-*.f32N/A
Applied rewrites97.0%
Final simplification97.0%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* (* x (PI)) tau))) (* 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\\
1 \cdot \frac{\sin t\_1}{t\_1}
\end{array}
\end{array}
Initial program 97.8%
Taylor expanded in x around 0
Applied rewrites72.0%
Final simplification72.0%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (* tau (PI))))) (* (/ 1.0 t_1) (sin t_1))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := x \cdot \left(tau \cdot \mathsf{PI}\left(\right)\right)\\
\frac{1}{t\_1} \cdot \sin t\_1
\end{array}
\end{array}
Initial program 97.8%
/-rgt-identityN/A
clear-numN/A
lower-/.f32N/A
lift-*.f32N/A
associate-/r*N/A
lower-/.f32N/A
lower-/.f3297.0
lift-*.f32N/A
*-commutativeN/A
lower-*.f3297.0
Applied rewrites97.0%
Taylor expanded in x around 0
Applied rewrites71.7%
lift-*.f32N/A
lift-/.f32N/A
associate-*l/N/A
associate-/l*N/A
Applied rewrites71.9%
Final simplification71.9%
(FPCore (x tau) :precision binary32 (+ (* (pow (* x (PI)) 2.0) -0.16666666666666666) 1.0))
\begin{array}{l}
\\
{\left(x \cdot \mathsf{PI}\left(\right)\right)}^{2} \cdot -0.16666666666666666 + 1
\end{array}
Initial program 97.8%
Taylor expanded in x around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f32N/A
Applied rewrites64.3%
Taylor expanded in tau around 0
Applied rewrites64.6%
Applied rewrites65.6%
Final simplification65.6%
(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 97.8%
Taylor expanded in x around 0
Applied rewrites64.6%
herbie shell --seed 2024268
(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)))))