replicate

I have defined a custom function, like this: my.fun = function() { for (i in 1:1000) { ... for (j in 1:20) { ... } } return(output) } which returns an output matrix, output , composed by 1000 rows and 20 columns. What I need to do is to repeat the function say 5 times and to store the five output results into a brand new matrix, say final , but without using another for-loop (this for making the code clearer, and also because in a second moment I would like to try to parallelize these additional 5 repetitions). Hence final should be a matrix with 5000 rows and 20 columns (the rationale behind

I have a large MySQL database, lets call it live_db , which I want to replicate on the same machine to provide a test system to play around with ( test_db ), including table structure and data. In regular intervals I want to update the test_db with the content of the live_db ; if possible incremental. Is there some built-in mechanism in MySQL to do that? I think that master-slave replication is not the thing I want since it should be possible to alter data in the test_db . These changes do not have to be preserved, though. Regards, CGD The mysql command line client will accept a stream of SQL

I have the following code set.seed(30) nsim <- 50 ## NUMBER OF REPLICATIONS demand <- c(12,13,24,12,13,12,14,10,11,10) res <- replicate(nsim, { load <- runif(10,11,14) diff <- load - demand ## DIFFERENCE BETWEEN DEMAND AND LOAD return(sum(diff < 0)) }) res [1] 6 5 7 4 4 5 4 3 6 4 5 5 5 4 2 5 3 3 3 5 3 2 4 6 5 4 4 3 5 6 4 4 3 6 5 3 5 5 4 3 3 [42] 6 4 4 4 6 6 5 4 5 I have a huge data set and the question is what is the fastest way of calculating the mean for every replication. For example the res in first replication is 6 so the result should be 6/1=6 for the second 6+5/2=5.5 for the third 6+5+7

We want to get an array that looks like this: 1,1,1,2,2,2,3,3,3,4,4,4,1,1,1,2,2,2,3,3,3,4,4,4,1,1,1,2,2,2,3,3,3,4,4,4 What is the easiest way to do it? 42- You can do it with a single rep call. The each and times parameters are evaluated sequentially with the each being done first. rep(1:4, times=3, each=3) #[1] 1 1 1 2 2 2 3 3 3 4 4 4 1 1 1 2 2 2 3 3 3 4 4 4 1 1 1 2 2 2 3 3 3 4 4 4 Or, simpler (assuming you mean a vector, not an array) rep(rep(1:4,each=3),3) 42-'s answer will work if your sequence of numbers incrementally increases by 1. However, if you want to include a sequence of numbers