On 9/28/2009 4:07 AM, Andrewjohnclose wrote:> Hi, I am trying to produce an xyplot with a regression line. The data
should
> be represented as log/log but when I fit the lmline I receive an error
> message - the plot is fine without the log transformation, but the then the
> plot is meaningless. I know it must be something simple, but I just
can't
> see it. Hope someone can help...
>
> Thanks.
What do you expect to happen with the values of 0 in Pk? Have a look
at this:
log(rwpk$Pk)
[1] -1.108663 -1.698269 -2.551046 -2.796881
[5] -2.733368 -2.796881 -3.352407 -3.352407
[9] -4.074542 -3.244194 -4.074542 -4.342806
[13] -3.506558 -5.521461 -4.342806 -4.074542
[17] -4.342806 -3.506558 -4.342806 -4.342806
[21] -Inf -3.816713 -4.342806 -4.710531
[25] -4.342806 -Inf -Inf -4.074542
[29] -5.521461 -4.342806 -4.710531 -5.521461
[33] -5.521461 -5.521461 -5.521461 -5.521461
[37] -Inf -Inf -Inf -5.521461
[41] -Inf -Inf -5.521461 -Inf
[45] -Inf -Inf -5.521461 -Inf
[49] -Inf -Inf -Inf -Inf
[53] -Inf -5.521461 -Inf -Inf
[57] -Inf -Inf -Inf -Inf
[61] -Inf -Inf -Inf -5.521461
If you want to ignore the zeros, perhaps you could do this:
library(lattice)
rwpk <-
read.csv(file='http://www.nabble.com/file/p25641684/rwpk.csv')
xyplot(log(Pk) ~ log(k), data=subset(rwpk, Pk !=0),
type=c('p','r'))
> xyplot(log(Pk)~log(k),data=rwpk,cex=1,
> panel=function(x,y){
> panel.grid(h=-1, v=-1)
> panel.xyplot(x,y,cex=1.0)
> panel.lmline(x,y)
> })
>
> http://www.nabble.com/file/p25641684/rwpk.csv rwpk.csv
--
Chuck Cleland, Ph.D.
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