
(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_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 97.6%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* (* tau x) (PI))) (t_2 (* x (PI)))) (* (/ (sin t_1) t_1) (/ (sin t_2) t_2))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \left(tau \cdot x\right) \cdot \mathsf{PI}\left(\right)\\
t_2 := x \cdot \mathsf{PI}\left(\right)\\
\frac{\sin t\_1}{t\_1} \cdot \frac{\sin t\_2}{t\_2}
\end{array}
\end{array}
Initial program 97.6%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-*r*N/A
lower-*.f32N/A
lower-*.f3297.0
Applied rewrites97.0%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-*l*N/A
lift-*.f32N/A
lift-*.f3297.5
Applied rewrites97.5%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* (PI) x)) (t_2 (* tau t_1))) (* (sin t_1) (/ (/ (sin t_2) t_2) t_1))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \mathsf{PI}\left(\right) \cdot x\\
t_2 := tau \cdot t\_1\\
\sin t\_1 \cdot \frac{\frac{\sin t\_2}{t\_2}}{t\_1}
\end{array}
\end{array}
Initial program 97.6%
lift-*.f32N/A
*-commutativeN/A
lift-/.f32N/A
associate-*l/N/A
associate-/l*N/A
lower-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-/.f3297.5
Applied rewrites97.5%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* x (PI))) (t_2 (* tau t_1))) (* (sin t_2) (/ (/ (sin t_1) (* t_2 x)) (PI)))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := x \cdot \mathsf{PI}\left(\right)\\
t_2 := tau \cdot t\_1\\
\sin t\_2 \cdot \frac{\frac{\sin t\_1}{t\_2 \cdot x}}{\mathsf{PI}\left(\right)}
\end{array}
\end{array}
Initial program 97.6%
lift-*.f32N/A
lift-/.f32N/A
associate-*r/N/A
lower-/.f32N/A
Applied rewrites97.4%
Applied rewrites97.1%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* (PI) x))) (* (/ (sin (* t_1 tau)) (* tau (* (PI) (PI)))) (/ (sin t_1) (* x x)))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \mathsf{PI}\left(\right) \cdot x\\
\frac{\sin \left(t\_1 \cdot tau\right)}{tau \cdot \left(\mathsf{PI}\left(\right) \cdot \mathsf{PI}\left(\right)\right)} \cdot \frac{\sin t\_1}{x \cdot x}
\end{array}
\end{array}
Initial program 97.6%
lift-*.f32N/A
*-commutativeN/A
lift-/.f32N/A
associate-*l/N/A
associate-/l*N/A
lower-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-/.f3297.5
Applied rewrites97.5%
Taylor expanded in x around inf
*-commutativeN/A
associate-*r*N/A
times-fracN/A
lower-*.f32N/A
Applied rewrites96.4%
Final simplification96.4%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* (PI) x)) (t_2 (* tau t_1))) (* t_1 (/ (/ (sin t_2) t_2) t_1))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \mathsf{PI}\left(\right) \cdot x\\
t_2 := tau \cdot t\_1\\
t\_1 \cdot \frac{\frac{\sin t\_2}{t\_2}}{t\_1}
\end{array}
\end{array}
Initial program 97.6%
lift-*.f32N/A
*-commutativeN/A
lift-/.f32N/A
associate-*l/N/A
associate-/l*N/A
lower-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-/.f3297.5
Applied rewrites97.5%
Taylor expanded in x around 0
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3268.8
Applied rewrites68.8%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* (* (PI) x) tau))) (/ (* (PI) (/ (sin t_1) (PI))) t_1)))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \left(\mathsf{PI}\left(\right) \cdot x\right) \cdot tau\\
\frac{\mathsf{PI}\left(\right) \cdot \frac{\sin t\_1}{\mathsf{PI}\left(\right)}}{t\_1}
\end{array}
\end{array}
Initial program 97.6%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-*r*N/A
lower-*.f32N/A
lower-*.f3297.0
Applied rewrites97.0%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-*l*N/A
lift-*.f32N/A
lift-*.f3297.5
Applied rewrites97.5%
lift-*.f32N/A
*-commutativeN/A
lift-/.f32N/A
lift-*.f32N/A
associate-/r*N/A
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f32N/A
Applied rewrites97.1%
Taylor expanded in x around 0
lower-PI.f3268.7
Applied rewrites68.7%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* (PI) x))) (/ (* (sin t_1) tau) (* t_1 tau))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \mathsf{PI}\left(\right) \cdot x\\
\frac{\sin t\_1 \cdot tau}{t\_1 \cdot tau}
\end{array}
\end{array}
Initial program 97.6%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-*r*N/A
lower-*.f32N/A
lower-*.f3297.0
Applied rewrites97.0%
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-*l*N/A
lift-*.f32N/A
lift-*.f3297.5
Applied rewrites97.5%
lift-*.f32N/A
*-commutativeN/A
lift-/.f32N/A
lift-*.f32N/A
associate-/r*N/A
lift-/.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
lift-*.f32N/A
associate-*l*N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f32N/A
Applied rewrites97.1%
Taylor expanded in tau around 0
*-commutativeN/A
lower-*.f32N/A
lower-sin.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3261.7
Applied rewrites61.7%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* (PI) x))) (/ (sin t_1) t_1)))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \mathsf{PI}\left(\right) \cdot x\\
\frac{\sin t\_1}{t\_1}
\end{array}
\end{array}
Initial program 97.6%
lift-*.f32N/A
lift-/.f32N/A
associate-*r/N/A
lower-/.f32N/A
Applied rewrites97.4%
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.f3261.7
Applied rewrites61.7%
Final simplification61.7%
(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 97.6%
Taylor expanded in x around 0
Applied rewrites61.0%
herbie shell --seed 2024337
(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)))))