[R] ellipse in pairs plot

[Kaveh Vakili]

Dear list moderator,

I'm sending you a solution i found to the question i asked the list yesterday (i have not been able to figure out how to post it to the list directly).


elly<-function(w,col=array(1,dim(w)[1]),pch=array(1,dim(w)[1])){
	p<-dim(w)[2]
	op<-par(mfrow=c(3,3),mar=c(0,0,0,0)+1,oma=c(1,1,1,1))
	c1<-rep(1:p,p)
	c2<-sort(c1)
	dan<-covMcd(w)
	for (i in 1:p^2) {
		if(c1[i]!=c2[i]){
			plot(w[,c(c1[i],c2[i])],xlab="",ylab="",xaxt="n",yaxt="n",main="",col=col,pch=pch)
			grid()
			ava<-c(dan$cov[c1[i],c1[i]],dan$cov[c1[i],c2[i]],dan$cov[c1[i],c2[i]],dan$cov[c2[i],c2[i]])
			ellipse(mu=dan$center[c(c1[i],c2[i])],sigma=matrix(ava,2,2),col=max(col)+1)	
		} else {
			plot(density(w[,c2[i]],from=min(w[,c2[i]]),to=max(w[,c2[i]])),xlab="",ylab="",xaxt="n",yaxt="n",main="",xlim=range(w[,c2[i]]),type="h",col="light grey")
		}
		if(c1[i]!=c2[i]){
			if(c1[i]==1){
				axis(2)
			}
			if(c2[i]==1){
				axis(3)
			}
			if(c1[i]==p){
				axis(4)
			}
			if(c2[i]==p){
				axis(1)
			}
		}
		if(i==1){
			axis(3)
		}
		if(i==p^2){
			axis(1)
		}
	}
	par(op)
}



>Hi dear list,
>
>I'm scrambling with this:
>
>i have a p-dimensional data frame for which i want to have a pairs() plot, with ellipse added in each lower.panel.
>
>I want the ellipse's parameter (mu, sigma) to be extracted from the appropriate entries in a pre-computed matrix ("dab" in the code below).
>
>Can it be done ?
>
>Thanks in advance, 
>
>
>melly<-function (x, y, col = par("col"), bg = NA, pch = par("pch"),cex = 1){
>    points(x, y, pch = pch, col = col, bg = bg, cex = cex)
>    ok <- is.finite(x) & is.finite(y)
>    if (any(ok)) 
>        ellipse(mu=dab$center[?],sigma=dab$cov[?,?])
>}
>
>pairs(wf[,1:5],diag.panel=bagwag,col=wc,pch=wp,cex=.5,lower.panel=melly)
>
>
> no attachments  have been sent 
>
>