In a previous post, I showed how to determine the best starting lineup to draft in an auction draft using an optimizer tool.  In this post, I use a Shiny app in R to determine the best possible players to pick in a fantasy... [Read more...]

StarCluster is a utility for creating and managingdistributed computing clusters hosted on Amazon's Elastic ComputeCloud (EC2). StarCluster utilizes Amazon´s EC2 web service to createand destroy clusters of Linux virtual machines on demand. Justin Riley http://star.mit.edu/cluster/docs/latest/index.html StarCluster documentation StarCluster provides a convenient ... [Read more...]

With this post, I want to introduce the new ‘propagate’ package on CRAN. It has one single purpose: propagation of uncertainties (“error propagation”). There is already one package on CRAN available for this task, named ‘metRology’ (http://cran.r-project.org/web/packages/metRology/index.html). ‘propagate’ has some additional functionality ... [Read more...]

One of my favorite sources of good ideas is looking at the GitHub repositories of others and modeling my repos after the good ideas I see others doing. Here's Steve Jobs on stealing ideas: In the past few weeks I've … Continue reading → [Read more...]

Today, I take my first shots at ranking Major League Baseball (MLB) teams. I see my efforts at prediction and ranking an ongoing process so that my models improve, the data I incorporate are more meaningful, and ultimately my predictions are largely accurate. For the first attempt, let’s rank ... [Read more...]

Last Thursday, there was a UM library network drink. And as I see a library where knowledge is found, and libraries still rarely think of knowledge as ever being able to be stored outside books and papers, I was happy to see the library promoting the D... [Read more...]

A useful property of mixed effects and Bayesian hierarchical models is that lower level estimates are shrunk towards the more stable estimates further up the hierarchy. To use a time honoured example you might be modelling the effect of a new teaching method on performance at the classroom level. Classes ... [Read more...]

Summary: Put a plaintext file named CITATION in the root directory of your code, and put information in it about how to cite your software. Go on, do it now – it’ll only take two minutes! Software is very important in science – but good software takes time and effort that ... [Read more...]

Some of my fellow scientists have it easy. They use predefined methods like linear regression and ANOVA to test simple hypotheses; they live in the innocent world of bivariate plots and lm(). Sometimes they notice that the data have odd histograms and they use glm(). The more educated ones use … ... [Read more...]

Exegetic Analytics extols the wonders of foreach package for iterative operations that go beyond the standard "for" loop in R. For example, here's a neat (if not optimally efficient) construct using filters to calculate the primes less than 100: foreach(n = 1:100, .combine = c) %:% when (isPrime(n)) %do% n The open-source team ... [Read more...]

The slides for my ECVP tutorial on classification images are available here. Try this alternative version if the equations look funny. (image from Mineault et al. 2009) The slides are in HTML and contain some interactive elements. They’re the result of experimenting with R Markdown, D3 and pandoc. You write ... [Read more...]

One of the most frequently used string recognition algorithms out there is regex and R implements regex.  However, users can often be frustrated with how despite taking examples verbatim from many sources such as stackoverflow they do not seem to ... [Read more...]

A new little OpenCPU app allows you to knit and markdown in the browser. It has a fancy pants code editor which automatically updates the output after 3 seconds of inactivity. It uses the Ace web editor with mode-r.js (thanks to RStudio for making the latter available). Like all OpenCPU ... [Read more...]

In a previous post, I showed how to determine the best starting lineup to draft using an optimizer tool.  The optimizer identifies the players that maximize your projected points within your risk tolerance.  The optimizer does not take i... [Read more...]

When plotting time series data, you might want to bin the values so that each data point corresponds to the sum for a given month or week. This post will show an easy way to use cut and ggplot2's stat_summary to plot month totals in R wi... [Read more...]

I was working on a project yesterday where I needed to amortize out a bunch of loans to calculate the total interest a borrower would pay if he or she paid the minimum monthly payment for the full term of the loan. I couldn’t find any package in R ... [Read more...]

by Joseph Rickert I was recently looking through upcoming Coursera offerings and came across the course Coding the Matrix: Linear Algebra through Computer Science Applications taught by Philip Klein from Brown University. This looks like a fine course; but why use Python to teach linear algebra? I suppose this is ... [Read more...]

This post shares the video from the talk presented in August 2013 by Ross Gayler on Credit Scoring and R at Melbourne R Users. Credit scoring tends to involve the balancing of mutually contradictory objectives spiced with a liberal dash … Continue reading → [Read more...]

For online businesses, Repeat Purchase Rate is one of the critical metrics of the business performance. Higher repeat purchase rate means more active members, and thus leads to higher profit. “Customer Latency refers to the average time between customer activity events, for example, making a purchase, calling the help desk, ... [Read more...]

TV Show Cancellations: Myths and Models TV shows are amazing ways to waste time and, on occasion, the story is so good that you actually start to care. The problem is that some shows get cancelled before they jump the shark. Classic examples are shows like Firefly or Arrested Development. ... [Read more...]