| image {spam} | R Documentation |
The function creates a grid of colored rectangles with
colors corresponding to the values in z.
image(x, ...)
x |
matrix of class spam or spam.chol.NgPeyton. |
... |
any other arguments passed
to image.default and plot. |
getOption('imagesize') determines if the sparse matrix is
coerced into a matrix and the plotted similarly to image.default or if
the matrix is simply represented as a scatterplot with
pch=".". The points are scaled according to
cex*spam.getOption('cex')/(nrow+ncol).
For some devices or for non-square matrices,
cex needs probably some adjustment.
The a zero matrix in spam format has as (1,1) entry the value
zero and only missing entries are interpreted as NA in the
scatter plot.
Reinhard Furrer
display and spam.options.
The code is based on image of graphics.
set.seed(13) nz <- 8 ln <- nz smat <- spam(0,ln,ln) smat[ cbind(sample(ln,nz),sample(ln,nz))] <- 1:nz par(mfcol=c(1,2),pty='s') spam.options( imagesize=1000) image(smat)#better: col=tim.colors(nz)) spam.options( imagesize=10) image(smat)#better: col=tim.colors(nz)) nz <- 128 ln <- nz^2 smat <- spam(0,ln,ln) smat[cbind(sample(ln,nz),sample(ln,nz))] <- 1:nz par(mfcol=c(1,1),pty='s') image(smat,cex=100)#better:, col=tim.colors(nz))