
(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 11 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{\sin 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
clear-numN/A
un-div-invN/A
frac-2negN/A
associate-/r/N/A
lower-*.f32N/A
Applied rewrites97.9%
Applied rewrites97.7%
lift-/.f32N/A
lift-*.f32N/A
lift-/.f32N/A
associate-/r/N/A
associate-/r/N/A
Applied rewrites98.0%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* (PI) x)) (t_2 (* tau t_1))) (/ (* (sin t_1) (sin t_2)) (* t_1 t_2))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \mathsf{PI}\left(\right) \cdot x\\
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
lift-/.f32N/A
clear-numN/A
un-div-invN/A
frac-2negN/A
associate-/r/N/A
lower-*.f32N/A
Applied rewrites97.9%
lift-*.f32N/A
lift-/.f32N/A
lift-/.f32N/A
associate-/l/N/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
Applied rewrites97.8%
lift-/.f32N/A
lift-/.f32N/A
associate-/r/N/A
associate-*l/N/A
*-commutativeN/A
lift-/.f32N/A
associate-/l*N/A
lift-*.f32N/A
lift-/.f32N/A
Applied rewrites97.7%
lift-*.f32N/A
lift-*.f32N/A
associate-*r*N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
swap-sqrN/A
lift-neg.f32N/A
lift-neg.f32N/A
sqr-negN/A
swap-sqrN/A
lift-*.f32N/A
lift-*.f32N/A
associate-*r*N/A
lift-*.f32N/A
lower-*.f3297.7
Applied rewrites97.7%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* (PI) x))) (/ (* (sin t_1) (sin (* tau t_1))) (* (* tau (* x x)) (* (PI) (PI))))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \mathsf{PI}\left(\right) \cdot x\\
\frac{\sin t\_1 \cdot \sin \left(tau \cdot t\_1\right)}{\left(tau \cdot \left(x \cdot x\right)\right) \cdot \left(\mathsf{PI}\left(\right) \cdot \mathsf{PI}\left(\right)\right)}
\end{array}
\end{array}
Initial program 98.0%
lift-*.f32N/A
lift-/.f32N/A
clear-numN/A
un-div-invN/A
frac-2negN/A
associate-/r/N/A
lower-*.f32N/A
Applied rewrites97.9%
lift-*.f32N/A
lift-/.f32N/A
lift-/.f32N/A
associate-/l/N/A
lift-*.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
Applied rewrites97.8%
lift-/.f32N/A
lift-/.f32N/A
associate-/r/N/A
associate-*l/N/A
*-commutativeN/A
lift-/.f32N/A
associate-/l*N/A
lift-*.f32N/A
lift-/.f32N/A
Applied rewrites97.7%
Taylor expanded in x around 0
associate-*r*N/A
lower-*.f32N/A
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
unpow2N/A
lower-*.f32N/A
lower-PI.f32N/A
lower-PI.f3296.8
Applied rewrites96.8%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* (PI) x))) (* (/ 1.0 t_1) (* (/ 1.0 tau) (sin (* tau t_1))))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \mathsf{PI}\left(\right) \cdot x\\
\frac{1}{t\_1} \cdot \left(\frac{1}{tau} \cdot \sin \left(tau \cdot t\_1\right)\right)
\end{array}
\end{array}
Initial program 98.0%
lift-*.f32N/A
lift-/.f32N/A
associate-*r/N/A
clear-numN/A
associate-/r/N/A
lower-*.f32N/A
lower-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lift-/.f32N/A
div-invN/A
Applied rewrites97.2%
Taylor expanded in x around 0
lower-/.f3269.9
Applied rewrites69.9%
(FPCore (x tau) :precision binary32 (* (/ x (* (PI) tau)) (/ (sin (* (* (PI) x) tau)) (* x x))))
\begin{array}{l}
\\
\frac{x}{\mathsf{PI}\left(\right) \cdot tau} \cdot \frac{\sin \left(\left(\mathsf{PI}\left(\right) \cdot x\right) \cdot tau\right)}{x \cdot x}
\end{array}
Initial program 98.0%
lift-*.f32N/A
lift-/.f32N/A
clear-numN/A
un-div-invN/A
frac-2negN/A
associate-/r/N/A
lower-*.f32N/A
Applied rewrites97.9%
Taylor expanded in x around inf
*-commutativeN/A
*-commutativeN/A
associate-*r*N/A
times-fracN/A
lower-*.f32N/A
Applied rewrites96.8%
Taylor expanded in x around 0
Applied rewrites69.9%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* (PI) x))) (/ 1.0 (/ 1.0 (/ (sin t_1) t_1)))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \mathsf{PI}\left(\right) \cdot x\\
\frac{1}{\frac{1}{\frac{\sin t\_1}{t\_1}}}
\end{array}
\end{array}
Initial program 98.0%
lift-*.f32N/A
lift-/.f32N/A
associate-*r/N/A
clear-numN/A
associate-/r/N/A
lower-*.f32N/A
lower-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lift-/.f32N/A
div-invN/A
Applied rewrites97.2%
Taylor expanded in tau around 0
lower-sin.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3263.1
Applied rewrites63.1%
lift-*.f32N/A
lift-/.f32N/A
associate-*l/N/A
*-lft-identityN/A
lift-*.f32N/A
associate-/r*N/A
clear-numN/A
lower-/.f32N/A
Applied rewrites63.1%
lift-/.f32N/A
clear-numN/A
lower-/.f32N/A
lift-/.f32N/A
associate-/l/N/A
lift-*.f32N/A
Applied rewrites63.2%
(FPCore (x tau) :precision binary32 (let* ((t_1 (* (PI) x))) (/ 1.0 (/ t_1 (sin t_1)))))
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \mathsf{PI}\left(\right) \cdot x\\
\frac{1}{\frac{t\_1}{\sin t\_1}}
\end{array}
\end{array}
Initial program 98.0%
lift-*.f32N/A
lift-/.f32N/A
associate-*r/N/A
clear-numN/A
associate-/r/N/A
lower-*.f32N/A
lower-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lift-/.f32N/A
div-invN/A
Applied rewrites97.2%
Taylor expanded in tau around 0
lower-sin.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3263.1
Applied rewrites63.1%
lift-*.f32N/A
lift-/.f32N/A
associate-*l/N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
clear-numN/A
lower-/.f32N/A
Applied rewrites63.2%
(FPCore (x tau) :precision binary32 (/ 1.0 (* (/ x (sin (* (PI) x))) (PI))))
\begin{array}{l}
\\
\frac{1}{\frac{x}{\sin \left(\mathsf{PI}\left(\right) \cdot x\right)} \cdot \mathsf{PI}\left(\right)}
\end{array}
Initial program 98.0%
lift-*.f32N/A
lift-/.f32N/A
associate-*r/N/A
clear-numN/A
associate-/r/N/A
lower-*.f32N/A
lower-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lift-/.f32N/A
div-invN/A
Applied rewrites97.2%
Taylor expanded in tau around 0
lower-sin.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3263.1
Applied rewrites63.1%
lift-*.f32N/A
lift-/.f32N/A
associate-*l/N/A
*-lft-identityN/A
lift-*.f32N/A
associate-/r*N/A
clear-numN/A
lower-/.f32N/A
Applied rewrites63.1%
lift-/.f32N/A
lift-/.f32N/A
associate-/r/N/A
lower-*.f32N/A
lower-/.f3263.1
Applied rewrites63.1%
(FPCore (x tau) :precision binary32 (/ (/ (sin (* (PI) x)) (PI)) x))
\begin{array}{l}
\\
\frac{\frac{\sin \left(\mathsf{PI}\left(\right) \cdot x\right)}{\mathsf{PI}\left(\right)}}{x}
\end{array}
Initial program 98.0%
lift-*.f32N/A
lift-/.f32N/A
associate-*r/N/A
clear-numN/A
associate-/r/N/A
lower-*.f32N/A
lower-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lift-/.f32N/A
div-invN/A
Applied rewrites97.2%
Taylor expanded in tau around 0
lower-sin.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3263.1
Applied rewrites63.1%
lift-*.f32N/A
lift-/.f32N/A
associate-*l/N/A
*-lft-identityN/A
lift-*.f32N/A
associate-/r*N/A
lower-/.f32N/A
Applied rewrites63.1%
(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 98.0%
lift-*.f32N/A
lift-/.f32N/A
associate-*r/N/A
clear-numN/A
associate-/r/N/A
lower-*.f32N/A
lower-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
lower-*.f32N/A
lift-/.f32N/A
div-invN/A
Applied rewrites97.2%
Taylor expanded in tau around 0
lower-sin.f32N/A
*-commutativeN/A
lower-*.f32N/A
lower-PI.f3263.1
Applied rewrites63.1%
lift-*.f32N/A
*-commutativeN/A
lift-/.f32N/A
lift-*.f32N/A
*-commutativeN/A
lift-*.f32N/A
un-div-invN/A
lower-/.f3263.1
lift-*.f32N/A
*-commutativeN/A
lift-*.f3263.1
Applied rewrites63.1%
(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 rewrites62.4%
Final simplification62.4%
herbie shell --seed 2024325
(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)))))