On Tue, 13 May 2008, Charles Plessy wrote:
> Dear list,
>
> I realised by chance when analysing a 1521862 ? 8 matrix that plotting
> was much faster when using "." as the argument of `pch'.
Why is that surprising? Drawing a small square is rather easy compared to
a circle, say.
> I was just wondering if there were other ways to get this speed
> improvement: it is otherwise quite difficult to explore such big
> matrices, especially given that X11 redraws the plot whenever its window
> is covered/uncovered by another window, or when I switch virtual
> desktops.
That is a function of your X setup. R does ask for backing store to be
used, and so it seeems your setup is not doing so. Also, the
type="cairo"
in X11() will repaint from a backing pixmap.
You might want to contemplate better ways to visualize 1.5m points. It is
not clear what plot you are actually doing, but a density plot is likely
to be more informative (especially a 2D pairs plot of densities), or a
hexbin plot (from the BioC package or that name) or ....
>
> Best regards,
>
> --
> Charles Plessy,
> Wak?, Saitama, Japan
>
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--
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
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