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# linearly transforms a vector or matrix of numbers to a new range
rescale<-function(x,newrange) {
if(missing(x) | missing(newrange)) {
usage.string<-paste("Usage: rescale(x,newrange)\n",
"\twhere x is a numeric object and newrange is the new min and max\n",
sep="",collapse="")
stop(usage.string)
}
if(is.numeric(x) && is.numeric(newrange)) {
xna<-is.na(x)
if(all(xna)) return(x)
if(any(xna)) xrange<-range(x[!xna])
else xrange<-range(x)
# if x is constant, just return it
if(xrange[1] == xrange[2]) return(x)
mfac<-(newrange[2]-newrange[1])/(xrange[2]-xrange[1])
return(newrange[1]+(x-xrange[1])*mfac)
}
else {
warning("Only numeric objects can be rescaled")
return(x)
}
}
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