
(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 9 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 (* (* tau (PI)) x)) (t_2 (* (PI) x))) (/ (* (/ (sin t_1) t_2) (sin t_2)) t_1)))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \left(tau \cdot \mathsf{PI}\left(\right)\right) \cdot x\\
t_2 := \mathsf{PI}\left(\right) \cdot x\\
\frac{\frac{\sin t\_1}{t\_2} \cdot \sin t\_2}{t\_1}
\end{array}
\end{array}
Initial program 97.8%
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
lift-/.f32N/A
clear-numN/A
frac-timesN/A
*-lft-identityN/A
*-commutativeN/A
clear-numN/A
lift-/.f32N/A
Applied rewrites97.9%
lift-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-/r*N/A
div-invN/A
lift-/.f32N/A
Applied rewrites97.9%
lift-*.f32N/A
*-commutativeN/A
lift-/.f32N/A
lift-sin.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-PI.f32N/A
lift-*.f32N/A
lift-PI.f32N/A
lift-/.f32N/A
Applied rewrites98.0%
Final simplification98.0%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* (* tau (PI)) x)) (t_2 (* (PI) x))) (/ (* (sin t_1) (sin t_2)) (* t_1 t_2))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \left(tau \cdot \mathsf{PI}\left(\right)\right) \cdot x\\
t_2 := \mathsf{PI}\left(\right) \cdot x\\
\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
lower-/.f32N/A
Applied rewrites97.9%
lift-/.f32N/A
lift-*.f32N/A
associate-/l*N/A
lift-/.f32N/A
clear-numN/A
frac-timesN/A
*-lft-identityN/A
*-commutativeN/A
clear-numN/A
lift-/.f32N/A
Applied rewrites97.9%
lift-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-/r*N/A
div-invN/A
lift-/.f32N/A
Applied rewrites97.9%
lift-*.f32N/A
lift-/.f32N/A
associate-*r/N/A
lift-sin.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-PI.f32N/A
associate-*r/N/A
frac-2negN/A
Applied rewrites97.9%
Final simplification97.9%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* (PI) x)) (t_2 (* (* tau (PI)) x))) (/ (* (/ t_1 t_2) (sin t_2)) t_1)))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \mathsf{PI}\left(\right) \cdot x\\
t_2 := \left(tau \cdot \mathsf{PI}\left(\right)\right) \cdot x\\
\frac{\frac{t\_1}{t\_2} \cdot \sin t\_2}{t\_1}
\end{array}
\end{array}
Initial program 97.8%
lift-*.f32N/A
lift-/.f32N/A
associate-*r/N/A
lift-*.f32N/A
*-commutativeN/A
lift-PI.f32N/A
add-sqr-sqrtN/A
associate-*l*N/A
Applied rewrites97.2%
Taylor expanded in x around 0
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3270.8
Applied rewrites70.8%
lift-*.f32N/A
lift-*.f32N/A
associate-*r*N/A
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f3270.7
Applied rewrites70.7%
lift-*.f32N/A
lift-/.f32N/A
lift-/.f32N/A
frac-timesN/A
lift-*.f32N/A
associate-*r*N/A
lift-sqrt.f32N/A
lift-sqrt.f32N/A
rem-square-sqrtN/A
lift-PI.f32N/A
Applied rewrites71.1%
Final simplification71.1%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* (PI) x)) (t_2 (* tau t_1))) (/ 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{t\_1}{\frac{t\_1}{\sin t\_2} \cdot t\_2}
\end{array}
\end{array}
Initial program 97.8%
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
lift-/.f32N/A
clear-numN/A
frac-timesN/A
*-lft-identityN/A
*-commutativeN/A
clear-numN/A
lift-/.f32N/A
Applied rewrites97.9%
Taylor expanded in x around 0
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3271.1
Applied rewrites71.1%
Final simplification71.1%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* (PI) x)) (t_2 (* (* tau (PI)) x))) (* (/ (/ t_1 t_2) t_1) (sin t_2))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \mathsf{PI}\left(\right) \cdot x\\
t_2 := \left(tau \cdot \mathsf{PI}\left(\right)\right) \cdot x\\
\frac{\frac{t\_1}{t\_2}}{t\_1} \cdot \sin t\_2
\end{array}
\end{array}
Initial program 97.8%
lift-*.f32N/A
lift-/.f32N/A
associate-*r/N/A
lift-*.f32N/A
*-commutativeN/A
lift-PI.f32N/A
add-sqr-sqrtN/A
associate-*l*N/A
Applied rewrites97.2%
Taylor expanded in x around 0
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3270.8
Applied rewrites70.8%
lift-*.f32N/A
lift-*.f32N/A
associate-*r*N/A
*-commutativeN/A
lower-*.f32N/A
*-commutativeN/A
lower-*.f3270.7
Applied rewrites70.7%
lift-*.f32N/A
lift-/.f32N/A
lift-/.f32N/A
frac-timesN/A
Applied rewrites71.0%
Final simplification71.0%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* (PI) x))) (* (/ (sin (* tau t_1)) t_1) (/ 1.0 tau))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \mathsf{PI}\left(\right) \cdot x\\
\frac{\sin \left(tau \cdot t\_1\right)}{t\_1} \cdot \frac{1}{tau}
\end{array}
\end{array}
Initial program 97.8%
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
lift-/.f32N/A
clear-numN/A
frac-timesN/A
*-lft-identityN/A
*-commutativeN/A
clear-numN/A
lift-/.f32N/A
Applied rewrites97.9%
lift-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
associate-/r*N/A
div-invN/A
lift-/.f32N/A
Applied rewrites97.9%
Taylor expanded in x around 0
lower-/.f3270.9
Applied rewrites70.9%
Final simplification70.9%
(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 97.8%
lift-*.f32N/A
lift-/.f32N/A
associate-*l/N/A
lower-/.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.f3264.4
Applied rewrites64.4%
(FPCore (x tau) :precision binary32 (/ -1.0 (/ (PI) (/ (* (- x) (PI)) x))))
\begin{array}{l}
\\
\frac{-1}{\frac{\mathsf{PI}\left(\right)}{\frac{\left(-x\right) \cdot \mathsf{PI}\left(\right)}{x}}}
\end{array}
Initial program 97.8%
lift-*.f32N/A
lift-/.f32N/A
associate-*r/N/A
frac-2negN/A
lift-*.f32N/A
*-commutativeN/A
distribute-rgt-neg-inN/A
associate-/r*N/A
lower-/.f32N/A
Applied rewrites97.1%
Taylor expanded in x around 0
mul-1-negN/A
*-commutativeN/A
distribute-lft-neg-inN/A
mul-1-negN/A
lower-*.f32N/A
mul-1-negN/A
lower-neg.f32N/A
lower-PI.f3263.6
Applied rewrites63.6%
lift-/.f32N/A
lift-/.f32N/A
associate-/l/N/A
associate-/r*N/A
clear-numN/A
lower-/.f32N/A
Applied rewrites63.6%
Final simplification63.6%
(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 rewrites63.6%
herbie shell --seed 2024304
(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)))))