When I use grid.rect to print a multi-coloured grid, it is incredibly slow
compared to a single colour grid, or even a two colour grid.
I've set out some simplified examples below. This is something I run literally
thousands of times a day, so I would greatly appreciate any hints on how I
might improve the speed???
library(grid)
pushViewport(viewport(
width = unit(100, "native"),
height = unit(100, "native"),
xscale = c(0, 100),
yscale = c(0, 100),
))
pushViewport(viewport(
x = unit(10, "native"),
y = unit(10, "native"),
width = unit(100, "native"),
height = unit(200, "native"),
xscale = c(0, 100),
yscale = c(0, 200),
just = c("left", "bottom"),
angle = 10))
system.time(grid.rect(x = unit(rep(1:100, 200) , "native"),
y = unit(rep(1:200, each = 100), "native"),
width = unit(1, "native"),
height = unit(1, "native"),
gp = gpar(col = NA,
fill = "lightblue")
))
system.time(grid.rect(x = unit(rep(1:100, 200) , "native"),
y = unit(rep(1:200, each = 100), "native"),
width = unit(1, "native"),
height = unit(1, "native"),
gp = gpar(col = NA,
fill = rgb(1, 0, 0, 1:20000/40000))
))
My times for the two plots are:
user system elapsed
0.61 0.30 0.92
vs
user system elapsed
0.08 0.36 24.39
The time it takes to calculate the colours clearly doesn't explain the
difference:
system.time(rgb(1, 0, 0, 1:20000/20000))
user system elapsed
0 0 0
Even if I do a two coloured grid, it finishes as quickly as the single coloured
one, so my first interpretation is that the function finds the colours fairly
quickly, e.g.
system.time(grid.rect(x = unit(rep(1:100, 200) , "native"),
y = unit(rep(1:200, each = 100), "native"),
width = unit(1, "native"),
height = unit(1, "native"),
gp = gpar(col = NA,
fill = c("lightblue", "red"))
))
user system elapsed
0.51 0.18 0.70
Best regards,
Mikkel
> sessionInfo()
R version 2.12.0 (2010-10-15)
Platform: i386-pc-mingw32/i386 (32-bit)
locale:
[1] LC_COLLATE=English_Ireland.1252 LC_CTYPE=English_Ireland.1252
[3] LC_MONETARY=English_Ireland.1252 LC_NUMERIC=C
[5] LC_TIME=English_Ireland.1252
attached base packages:
[1] grid stats graphics grDevices utils datasets methods
[8] base
loaded via a namespace (and not attached):
[1] tools_2.12.0
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
