[BioC] Correlation plot in R

[lcarvalh at btk.fi]

I have a problem when  creating a correlation plot when called within a
function, if called directly there is no problem. Can anyone find out why? The
code is below.

Code:

load("norm.matrix.RData")

require(lattice)


#This works and the figure is produced:

png(file="correlation.png", width=600, height=600)
levelplot(cor(data), col.regions = rainbow(100,start=.1, end=.35),scales =
list(x = list(rot = 45)), ylab="", xlab="", main="" )
dev.off()


#The following does not produce a figure, why?

saveCorrelationPlot <- function(data, fName) {
	#quartz()
	x11()
	png(file=fName, width=600, height=600)
    	levelplot(cor(data), col.regions = rainbow(100,start=.1, end=.35),scales =
list(x = list(rot = 45)), ylab="", xlab="", main="" )
	dev.off()
}

saveCorrelationPlot(data, "correlation2.png")


Thanks,

Leonor