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Next: 5.1.4 Lax-Wendroff Scheme (LW) Up: 5.1 Initial Value Problems Previous: 5.1.2 Lax Scheme


5.1.3 Leapfrog Scheme (LF)

Use DST for $\partial/\partial t$: $
\partial u /\partial t \approx (u^{n+1}-u^{n-1})/2\Delta t
$ to find the leapfrog expression
    $\displaystyle \fbox{$ \displaystyle
\mbox{$\bf u$}_{j}^{n+1}-\mbox{$\bf u$}_{j}...
...\Delta x} \left[\, \mbox{$\bf j$}_{j+1}^{n}-\mbox{$\bf j$}_{j-1}^{n} \right]
$}$  

\begin{figure}\includegraphics[width=120pt]{figures/f5lf.ps}
\end{figure}


Stability requires once more that $
c\,\Delta t/\Delta x \leq 1
$ (CFL condition)

Franz J. Vesely Oct 2005
See also:
"Computational Physics - An Introduction," Kluwer-Plenum 2001