Color2D.matplot uniform color range

Hi Jim,
Thanks so much for your help. I have read several of your responses on this
mailing list and they have helped me out quite a bit as I have gotten more
and more used to R.

I am still a little confused here by your response.
I think you understood my requirements correctly.
In your words:
  I want to anchor the extremes of the scales regardless of the values in the
matrix.
  I want 1 color gradient for values between 0 and 1 with a lowerbound cutoff
at 0.5.
  I want a second color gradient for values between 1 and infinity with an
upper bound cutoff at 3.

The function now reads as follows:

make_Q_figure<-function(filename,alias){
  h0<- read.csv(file=filename,head=TRUE,sep=",",row.names=1)
  d =data.matrix(h0)
  cellcolors<-matrix(NA,nrow=20,ncol=20)
  d<- d[ind,ind]
  cellcolors[d>= 1&  d<  3]<- color.scale(c(1,3,d[d>= 1&  d<  3]),
cs1=1,cs2=c(1,0),cs3=c(1,0))[-1:2]
  cellcolors[d<1]<-
color.scale(c(0,1,d[d<1]),cs1=c(0,0,1),cs2=c(0,0,1),cs3=1)[-1:2]
  cellcolors[d>= 2]<-"red"

color2D.matplot(d,cellcolors=cellcolors,show.values=F,na.color="white",axes=FALSE,main=alias,
xlab="",ylab="")
  axis(1,at=0.5:19.5,labels=colnames(d))
  axis(2,at=0.5:19.5,labels=rev(rownames(d)))
}

However when I execute this function I get the following error:
Error in color.scale(c(0, 1, d[d<  1]), cs1 = c(0, 0, 1), cs2 = c(0, 0,  :
   only 0's may be mixed with negative subscripts