What is the R way of computing cumulative growth rates given a series of discrete values indexed .
For instance, given a matrix of 20 observations for each of 5 series (zz), what is the most straight forward technique in R for computing cumulative growth (zzcum) ? It seems for the solution I'm after might be imbedding the following cum growth rate calc as a function into a function call to apply, mapply, ...? zz = rnorm(100) dim(zz) = c(20,5) zz zzcum=matrix(nrow=20,ncol=5) zzcum zzcum[1,]=100*(1+zz[1,]/100) zzcum for(i in 2:20){zzcum[i,] = zzcum[i-1,]*(1+zz[i,]/100)} zzcum ------------------------------------------------------------ CONFIDENTIALITY NOTICE: This electronic mail transmission (i...{{dropped}} ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.