I tried your code and could not get it to run on my installation of R, so I may be missing something. But if you have a matrix of probabilities (call it probs) and want to simulate random binomial draws, can you not simply create a matrix of the same size of uniform random numbers (runif()) (call it rands), then do comparisons, thus,
draws <- 0 + (rands < probs) Ben Fairbank -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Economics Guy Sent: Tuesday, March 11, 2008 10:16 AM To: [EMAIL PROTECTED] Subject: [PS] [R] Generating a new matrix using rbinom and a matrix of probabilities. I am having a little trouble getting R to do something without writing a couple of very awkward loops. I have a matrix of probabilities and I want to generate a new matrix of ones and zeros where each element in the new matrix is the result of a draw from a binomial distribution where the probability of getting a 1 is the corresponding element in the matrix of probabilities. Example Code: -------------------------------------------- ## First I generate the matrix of probabilities for example purposes. probMatrix <- matrix(NA,5,5){ for (i in 1:5) probVectorI <- runif(5,0,1) probMatrix[i,] <- probVectorI } # Now I want to take each element in probMatrix and use it as the probability parameter in rbinom draw and generate a new matrix. Something like this: binomialMatrix <- rbinom(1,1,probMatrix) # But that does not work. I know I can run a loop across each vector of the matrix, but this seems like an bad way to do this. ---------------------------End Code-------------------------------- So any help would be appreciated. Thanks, EG ______________________________________________ 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. ______________________________________________ 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.
