Re: [R] quantreg speed

2014-11-16 Thread Yunqi Zhang
Hi Roger, Thank you for your reply. To my understanding, changing the regression method only helps to speed up the computation, but not necessarily solve the problem with 99th percentile that p-values for all the factors are 1.0. I wonder how I should interpret the result for 99th percentile, w

Re: [R] quantreg speed

2014-11-16 Thread Roger
You could try method = "pin". Sent from my iPhone > On Nov 16, 2014, at 1:40 AM, Yunqi Zhang wrote: > > Hi William, > > Thank you very much for your reply. > > I did a subsampling to reduce the number of samples to ~1.8 million. It > seems to work fine except for 99th percentile (p-values f

Re: [R] quantreg speed

2014-11-15 Thread Yunqi Zhang
Hi William, Thank you very much for your reply. I did a subsampling to reduce the number of samples to ~1.8 million. It seems to work fine except for 99th percentile (p-values for all the features are 1.0). Does this mean I’m subsampling too much? How should I interpret the result? tau: [1] 0.25

Re: [R] quantreg speed

2014-11-15 Thread William Dunlap
You can time it yourself on increasingly large subsets of your data. E.g., > dat <- data.frame(x1=rnorm(1e6), x2=rnorm(1e6), x3=sample(c("A","B","C"),size=1e6,replace=TRUE)) > dat$y <- with(dat, x1 + 2*(x3=="B")*x2 + rnorm(1e6)) > t <- vapply(n<-4^(3:10),FUN=function(n){d<-dat[seq_len(n),]; print

[R] quantreg speed

2014-11-15 Thread Yunqi Zhang
Hi all, I'm using quantreg rq() to perform quantile regression on a large data set. Each record has 4 fields and there are about 18 million records in total. I wonder if anyone has tried rq() on a large dataset and how long I should expect it to finish. Or it is simply too large and I should subsa