Hi all,
I'm working with a bunch of large graphs, and stumbled across
something useful. Probably many of you know this, but I didn't and so
others might benefit.
Using pch="." speeds up plotting considerably over using symbols.
x <- runif(1000000)
y <- runif(1000000)
system.time(plot(x, y, pch="."))
user system elapsed
1.042 0.030 1.077
user system elapsed
37.865 0.033 38.122
If you have enough points, the result is also more legible.
Choice of which pch symbol makes a difference too, the default pch=1 being
the slowest of what I tried, but "." is by far the speediest.
system.time(plot(x, y, pch=0))
user system elapsed
11.191 0.011 11.270
system.time(plot(x, y, pch=1))
user system elapsed
38.024 0.008 38.245
system.time(plot(x, y, pch=2))
user system elapsed
14.140 0.027 14.270
system.time(plot(x, y, pch=3))
user system elapsed
15.696 0.011 15.799
system.time(plot(x, y, pch=4))
user system elapsed
18.770 0.007 18.888
This is a vanilla R session, 2.13.1 for x86_64-redhat-linux-gnu. I
haven't tried it on any other OS, but it's making my life a lot
smoother right now.
Sarah