Here is a link to a wonderful ggplot2 tutorial: http://www.ceb-institute.org/bbs/wp-content/uploads/2011/09/handout_ggplot2.pdf by R. Saccilotto and the Basel Institute for Clinical Epidemiology …Continue reading »

I watched this video by Fernando Pérez a few days ago when I was reading a comment by James Correia Jr on Simply Statistics: This is absolutely a fantastic talk that I recommend everybody to watch (it is good in both the form and content). Not surprisingly, I started thinking ipython vs knitr. Corey Chivers said we could...

Triangle, square, pentagonal, hexagonal, heptagonal, and octagonal numbers are all figurate (polygonal) numbers and are generated by the following formulae: Triangle P3,n=n(n+1)/2 1, 3, 6, 10, 15, ... Square P4,n=n2 ...

Dear R-Users, a question: I am the author of the ‘qpcR’ package. Within this, there is a function ‘propagate’ that does error propagation based on Monte Carlo Simulation, permutation-based confidence intervals and Taylor expansion. For the latter I recently implemented a second-order Taylor expansion term that can correct for nonlinearity. The formulas are quite complex

nice ggplot intro tutorial. Just run the commands, about 6 pages = flexible 1-3 hours of learning, depending how much reading you want to pair it with by Ramon Saccilotto

Email One of the historic difficulties of doing research on urban energy systems has been the limited availability of data at sufficiently detailed spatial resolutions. Without this data, you might end up relying on aggregate information about the built environment, building occupants, and local geography that doesn't apply to the specifics of a particular neighbourhood

In many circumstances, you might want to connect R directly to a database to store and retrieve data. If the source database is an Oracle database, you have a number of options: ROracle RODBC RJDBC Using ROracle should theoretically… Read more ›

POSIXct is the signed number of seconds since “the epoch”. For example it was 1351298112 UTC (GMT) when I wrote this. (1351298112 UTC = Sat Oct 27, 2:35 am GMT = Fri Oct 26, 8:35 pm EST = Fri Oct 26, 5:35 pm PST = 2:35 pm HST) POSIXlt is one of many text | character | string formats such as: May 17, 2017 17/5/2017 17-5-17 05:24:39

A quick heads-up that I'll be presenting another brand-new webinar on Thursday next week (November 29). In Real-time Big Data Analytics: From Deployment to Production, I'll review the process of making predictive models work in real-live operational environments. I'll also tackle those ubiquitous buzz-words "real-time" and "big data", and the fact that they can mean very different things in...

At a meeting last night with some collaborators at the Vélobstacles project, I was excitedly told about the magic of IPython and it’s notebook functionality for reproducible research. This sounds familiar, I thought to myself. Using a literate programming approach to integrate computation with the communication of methodology and results has been at the core

A nice package can be both beautiful and functional. The image is CC by MIAD Communication Design. Inspired by Read more »

We introduced Rcpp 0.10.0 with a number of very nice new features a few days ago, and the activity on the rcpp-devel mailing list has been pretty responsive which is awesome. But because few things beat a nice example, this post tries to build some more excitement. We will illustrate how Rcpp attributes makes it really easy to add C++ code...

I'm really looking forward to useR! 2013 (the international conference for R users), and not just because it's being held in Spain next year (July 10-12). The program is already coming together, with a great lineup of invited speakers, including R-core member Duncan Murdoch and prolific package authoR Hadley Wickham. You too can be part of the program, by...

I spotted on R-bloggers a post discussing optimising the efficiency of programming accept-reject algorithms. While it is about SAS programming, and apparently supported by the SAS company, there are two interesting features with this discussion. The first one is about avoiding the dreaded loop in accept-reject algorithms. For instance, taking the case of the truncated-at-one

I gave this talk last night to the Melbourne Users of R Network. Examples

Last week we released version 0.1.5-4 of the ChainLadder package on CRAN. The R package provides methods which are typically used in insurance claims reserving. If you are new to R or insurance check out my recent talk on Using R in Insurance.The chain-ladder method which is a popular method in the insurance industry to forecast future...

A commenter on my previous blog entry has drawn my attention to an R function called hetglm() that estimates heteroskedastic probit models. This function is contained in the glmx package. The glmx package is not available on CRAN yet, but thankfully can be downloaded here. The hetglm() function has a number of computational advantages compared with

Quite a lot of people have had fun recently with prime factorization. It all started on The Math Less Traveled, then various versions of the prime factorization diagrams appeared (here, here, this animated one, etc., they are actually more or less listed here). So I wanted to have fun too and give a try...

It’s a lovely day. I took a walk around the campus after lunch. The scene was enjoyable in one deep autumn day. Before the afternoon work, I’d like to spend a few moments on the 24th Euler Problem. A permutation is an ordered arrangement of … Continue reading →