### Name: PMindex
### Title: Find the index of the exact match (PM) or background probes from
###   a probeAnno environment
### Aliases: PMindex BGindex
### Keywords: manip

### ** Examples

## library(davidTiling)
## data(davidTiling)
## data(probeAnno)
## pmind <- PMindex(probeAnno)
## mmind <- MMindex(probeAnno)
## bgind <- BGindex(probeAnno)
## boxplot(as.data.frame(log2(exprs(davidTiling))[pmind,]), outline=FALSE)           



