R

Getting from flat data a world of relationships to visualise with Gephi

Network analysis offers a perspective of the data that broadens and enriches any investigation. Many times we deal with data in which the elements are related, but we have them in a tabulated format that is difficult to import into network analysis tools. Relationship data require a definition of nodes and connections. Both parts have different structures and it is not possible to structure them in a single table, at least two would be needed.

Simple yet elegant Object-Oriented programming in R with S3

The R language is peculiar in many ways, and its approach to object-oriented (OO) programming is just one of them. Indeed, base R supports not one, but three different OO systems: S3, S4 and RC classes. And yet, probably none of them would qualify as a fully-fledged OO system before the astonished gaze of an expert in languages such as Python, C++ or Java. In this tutorial, we will review the S3 system, the simplest yet most elegant of them.

An introduction to Stan with R

Stan is a probabilistic programming language for specifying statistical models. Stan provides full Bayesian inference for continuous-variable models through Markov Chain Monte Carlo methods such as the No-U-Turn sampler, an adaptive form of Hamiltonian Monte Carlo sampling. Penalized maximum likelihood estimates are calculated using optimization methods such as the limited memory Broyden-Fletcher-Goldfarb-Shanno algorithm. Stan can be called through R using the rstan package, and through Python using the pystan package.

LSTM with Keras & TensorFlow

The aim of this tutorial is to show the use of TensorFlow with KERAS for classification and prediction in Time Series Analysis. The latter just implement a Long Short Term Memory (LSTM) model (an instance of a Recurrent Neural Network which avoids the vanishing gradient problem). Introduction The code below has the aim to quick introduce Deep Learning analysis with TensorFlow using the Keras back-end in R environment. Keras is a high-level neural networks API, developed with a focus on enabling fast experimentation and not for final products.

Online resources for teaching

In this session I will try to show some utilities present in the web. One of them will help us to execute R code from the web, using an online compiler, without installing any kind of software in our computers. The other one, it can help us to solve optimization problems by a graphics way. We can draw the restrictions, the feasible region, and others elements that we can need to solve the problems.

An introduction to Shiny II

This is our second session introducing Shiny, an R package that allows to develop interactive Apps in a familiar framework for regular R-users. During the first session we focused on the structure and workflow basics, and now, we will go further on input and output objects, reactivity, layouts and data handling. All these functionalities will be reviewed by product of developing a Shiny App. It will provide the grades to our students and, at the same time, they will be able to explore the data set by interacting with the App.

An introduction to Tensorflow

Tensorflow has been widely used for many applications in machine learning and deep learning. However, Tensorflow is more than that, it is a general purpose computing library. Based on that, people have created a rich ecosystem for quickly developing models. In this talk, I will show how statisticians can get most of the main features in Tensorflow such as automatic differentiation, optimization, and Bayesian analysis through a simple linear regression example.

An introduction to Shiny as a teaching resource

The main goal of this session is to show a regular R user how to develop his/her own interactive (web) application without much effort. For doing so, we introduce the Shiny R package that makes this task simple even for an R programmer that has never heard about HTML, CSS or JavaScript (or does not care about them at all). During the session, we will develop from scratch an interactive app that illustrates the law of large numbers.

Useful one-function R packages, big data solutions, and a message from Yoda

As the title reads, in this heterogeneous session we will see three topics of different interest. The first is a collection of three simple and useful one-function R packages that I use regularly in my coding workflow. The second collects some approaches to handling and performing linear regression with big data. The third brings in the freaky component: it presents tools to display graphical information in plain ASCII, from bivariate contours to messages from Yoda!