I’ve been an editor of JSS for the last few years, and as a result I tend to get email from people asking me about publishing papers describing R packages in JSS. So for all those wondering, here are some general comments.

## Posts Tagged ‘computing’:

## Generating tables in LaTeX

Typing tables in LaTeX can get messy, but there are some good tools to simplify the process. One I discovered this week is tablesgenerator.com, a web-based tool for generating LaTeX tables. It also allows the table to saved in other formats including HTML and Markdown. The interface is simple, but it does most things. For complicated tables, some additional formatting may be necessary.

## Getting a LaTeX system set up

Today I was teaching the honours students in econometrics and economics about LaTeX. Here are some brief instructions on how to set up a LaTeX system on different operating systems.

## Fast computation of cross-validation in linear models

The leave-one-out cross-validation statistic is given by where , are the observations, and is the predicted value obtained when the model is estimated with the th case deleted. This is also sometimes known as the PRESS (Prediction Residual Sum of Squares) statistic. It turns out that for linear models, we do not actually have to estimate the model times, once for each omitted case. Instead, CV can be computed after estimating the model once on the complete data set.

## Using old versions of R packages

I received this email yesterday: I have been using your ‘forecast’ package for more than a year now. I was on R version 2.15 until last week, but I am having issues with lubridate package, hence decided to update R version to R 3.0.1. In our organization even getting an open source application require us to go through a whole lot of approval processes. I asked for R 3.0.1, before I get approval for 3.0.1, a new version of R ( R 3.0.2 ) came out. Unfortunately for me forecast package was built in R3.0.2. Is there any version of forecast package that works in older version of R(3.0.1). I just don’t want to go through this entire approval war again within the organization. Please help if you have any work around for this This is unfortunately very common. Many corporate IT environments lock down computers to such an extent that it cripples the use of modern software like R which is continuously updated. It also affects universities (which should know better) and I am constantly trying to invent work-arounds to the constraints that Monash IT services place on staff and student computers. Here are a few thoughts that might help.

## Highlighting the web

Users of my new online forecasting book have asked about having a facility for personal highlighting of selected sections, as students often do with print books. We have plans to make this a built-in part of the platform, but for now it is possible to do it using a simple browser extension. This approach allows any website to be highlighted, so is even more useful than if we only had the facility on OTexts.org. There are several possible tools available. One of the simplest tools that allows both highlighting and annotations is Diigo.

## More time series data online

Earlier this week I had coffee with Ben Fulcher who told me about his online collection comprising about 30,000 time series, mostly medical series such as ECG measurements, meteorological series, birdsong, etc. There are some finance series, but not many other data from a business or economic context, although he does include my Time Series Data Library. In addition, he provides Matlab code to compute a large number of characteristics. Anyone wanting to test time series algorithms on a large collection of data should take a look. Unfortunately there is no R code, and no R interface for downloading the data.

## Hierarchical forecasting with hts v4.0

A new version of my hts package for R is now on CRAN. It was completely re-written from scratch. Not a single line of code survived. There are some minor syntax changes, but the biggest change is speed and scope. This version is many times faster than the previous version and can handle hundreds of thousands of time series without complaining.

## Automatic time series forecasting in Granada

In two weeks I am presenting a workshop at the University of Granada (Spain) on Automatic Time Series Forecasting. Unlike most of my talks, this is not intended to be primarily about my own research. Rather it is to provide a state-of-the-art overview of the topic (at a level suitable for Masters students in Computer Science). I thought I’d provide some historical perspective on the development of automatic time series forecasting, plus give some comments on the current best practices.

## New in forecast 5.0

Last week, version 5.0 of the forecast package for R was released. There are a few new functions and changes made to the package, which is why I increased the version number to 5.0. Thanks to Earo Wang for helping with this new version.