Hello! I have the following combinatorial problem. Consider the cumulative sums of all permutations of a given weight vector 'w'. I need to know how often weight in a certain position brings the cumulative sums equal or above the given threshold 'q'. In other words, how often each weight is decisive in raising the cumulative sum above 'q'?
Here is what I do: w <- c(3,2,1) # vector of weights q <- 4 # theshold # computes which coordinate of w is decisive in each permutation res <- sapply( permn(w), function(x) which(w == x[min(which(cumsum(x) >= q))]) ) # complies the frequencies prop.table( tabulate( res )) The problem I have is that when the weights are not unique, the which() function returns a list as opposed to a vector. I don’t know how to proceed when this happens, as tabulate does not work on lists. The answer, of course, should be that equal weights are “decisive” equally often. Can you help? Thanks a lot! Serguei Kaniovski ______________________________________________ R-help@r-project.org 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.
