Have you ever tried to find a lightweight yet nice theme for the R Markdown documents, like this page? Themes for R Markdown With the powerful rmarkdown package, we could easily create nice HTML document by adding some meta information in the he... [Read more...]

A Quick View of Recommender System The main task of recommender system is to predict unknown entries in the rating matrix based on observed values, as is shown in the table below: Each cell with number in it is the rating given by some user on a specific item, while ... [Read more...]

Introduction I have seen several conversations in Rcpp-devel mailing list asking how to compute numerical integration or optimization in Rcpp. While R in fact has the functions Rdqags, Rdqagi, nmmin, vmmin etc. in its API to accomplish such tasks, it is not so straightforward to use them with Rcpp. For ... [Read more...]

In January 2016, I was honored to receive an “Honorable Mention” of the John Chambers Award 2016. This article was written for R-bloggers, whose builder, Tal Galili, kindly invited me to write an introduction to the rARPACK package. A Short Story of rARPACK Eigenvalue decomposition is a commonly used technique in numerous ... [Read more...]

Thanks to the issue report by yufree and Yihui’s kind work, from version 1.6.10 (development version), knitr starts to support using showtext to change fonts in R plots. To demonstrate its usage, this document itself serves as an example. (Rmd source code) We first do some setup work, mainly about ... [Read more...]

Today I gave a presentation for GSO(Graduate Student Organization) of our department, mainly about the idea of dynamic document and its implementation using knitr. Here are the slides I showed in the talk, written with Markdown and knitr. [Read more...]

This is a pretty old topic in R graphics. A classical article in R NEWS, Non-standard fonts in PostScript and PDF graphics, describes how to use and embed system fonts in the PDF/PostScript device. More recently, Winston Chang developed the extrafont package, which makes the procedure much easier. A ... [Read more...]

Dr. Hadley Wickham is the Chief Scientist of RStudio and Assistant Professor of Statistics at Rice University. He is the developer of the famous R package ggplot2 for data visualization and the author of many other widely used packages like plyr and reshape2. On Sep 13, 2013 he gave a talk at ... [Read more...]

This title is a bit exaggerating since handwriting recognition is an advanced topic in machine learning involving complex techniques and algorithms. In this blog I’ll show you a simple demo illustrating how to recognize a single number (0 ~ 9) using R. The overall process is that, you draw a number in ... [Read more...]

This binary package supports R 2.13.x (32-bit/64-bit) and MySQL 5.5.16 (32-bit/64-bit). RMySQL 0.8-0 for MySQL 5.5.16 [Read more...]

It’s well known that R is a memory based software, meaning that datasets must be copied into memory before being manipulated. For small or medium scale datasets, this doesn’t cause any troubles. However, when you need to deal with larger ones, for instance, financial time series or log ... [Read more...]