Third Milano R net meeting April 18, 2013 @ 6.00 PM Fiori Oscuri Bistrot & Bar Via Fiori Oscuri, 3 Milano Further details will be published shortly. Stay connected!

Third Milano R net meeting April 18, 2013 @ 6.00 PM Fiori Oscuri Bistrot & Bar Via Fiori Oscuri, 3 Milano Further details will be published shortly. Stay connected!

A friend of mine asked me the other day how she could use the function optim in R to fit data. Of course there are functions for fitting data in R and I wrote about this earlier. However, she wanted to understand how to do this from scratch using optim. The function optim provides algorithms for general...

There are many ways to simulate a multivariate gaussian distribution assuming that you can simulate from independent univariate normal distributions. One of the most popular method is based on the Cholesky decomposition. Let’s see how Rcpp and Armadillo perform on this task. #include <RcppArmadillo.h> // ] using namespace Rcpp; // ] arma::mat mvrnormArma(int n, arma::vec mu, arma::mat sigma) { int ncols...

as.character() is your friendas.character() is your friend Sometimes when you open a data file (lets say a .csv), variables will be recognized as factor whereas it should be numeric. It is therefore tempting to simply convert the variable to numeric using as.numeric(). Big mistake! If...

This is a repost of the second part of an example that I posted last year but at the time I only had the PDF document (written in ). This is the second example to generate multivariate random associated data. This example shows how to generate ordinal, categorical, data. It is a little more complex than generating continuous

On Friday I traveled to Boulder, CO to update the Boulder BI Brain Trust on the latest news and updates from Revolution R Enterprise. While I was there, I was interviewed by BBBT president Claudia Imhoff. In a wide-ranging chat, we discussed: What's behind the Revolution Analytics momentum over the past year? How Business Intelligence relates to Data Science...

I gave a talk at the Spring ENAR meetings this morning on some of the technical aspects of creating the book. The session was on reproducible research and the slides are here. I was dinged for not using git for version control (we used dropbox for simp...