After seeing IPython Markdown Opportunities in IPython Notebooks and Rstudio in the feeds today I wondered how easy/hard it would be to write a handler for something like go code. After taking a look at Yihui Xie‘s knitr source it seemed like it would be fairly easy to ... [Read more...]

I had an email exchange with Jeff Malins, who asked several questions about growth curve analysis. I often get questions of this sort and Jeff agreed to let me post excerpts from our (email) conversation. The following has been lightly edited for clarity and to be more concise.Jeff asked:... [Read more...]

This will be my last post on this blog for an indefinite length of time. I will also include an … Continue reading → [Read more...]

The recent announcement of the start of egg rationing in the U.S. made me curious enough about the avian flu outbreak to try to dig into the numbers a bit. I finally stumbled upon a USDA site that had an embedded HTML table of flock outbreak statistics by state, ... [Read more...]

R’s main linear and nonlinear regression functions, lm() and nls(), report standard errors for parameter estimates under the assumption of homoscedasticity, a fancy word for a situation that rarely occurs in practice. The assumption is that the (conditional) variance of the response variable is the same at any set ... [Read more...]

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International Conference on Computational Social Science (ICCSS 2015) [Read more...]

I was told the Eurostat package would be interesting for me.  This is indeed true and now I want to use it to plot some data which are related core of some of the European policies; debt.In these plots I only show individual countries, not aggrega... [Read more...]

I was at the Microsoft Gaming data hackathon today. Gaming is very big business and companies rarely publish detailed game data. Through contacts one of the organizers was able to obtain two gaming datasets, both containing just under 300M of compressed of data. Illyriad supplied a random snapshot of anonymised ... [Read more...]

There are a lot of “winning” strategies for bull markets floating around. “Buy the pullbacks” is certainly one of them. Does this sound simple enough to implement to you? While I am no Sheldon Cooper (although I have a favorite couch seat), I still like to live in a somewhat ... [Read more...]

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Conrad put out a new minor release 5.200.1 of Armadillo yesterday. Armadillo is a powerful and expressive C++ template library for linear algebra aiming towards a good balance between speed and ease of use with a syntax deliberately close to a Matlab. Our corresponding RcppArmadillo release 0.5.200.1.0 is now on CRAN and ... [Read more...]

If your native code takes more than a few seconds to finish, it is a nice courtesy to the user to check for user interrupts (Ctrl-C) once in a while, say, every 1,000 or 1,000,000 iteration. The C-level API of R provides R_CheckUserInterrupt() for this (see 'Writing R Extensions' for more ... [Read more...]

At last month's BUILD conference for Microsoft developers in San Francisco, R was front-and-center on the keynote stage. In the keynote, Microsoft CVP Joseph Sirosh introduced the "language of data": open source R. Sirosh encouraged the audience to learn R, saying "if there is a single language that you choose ... [Read more...]

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In programming, sometimes it’s useful to write a macro rather than a function. (Don’t worry if you’ve never heard the term before.) In this post, I’ll give an example of use of macros in R. using the gtools package on CRAN. I wanted to write some ... [Read more...]

The current version 1.8.1 of my sjPlot package has two new functions to easily summarize mixed effects models as HTML-table: sjt.lmer and sjt.glmer. Both are very similar, so I focus on showing how to use sjt.lmer here. Linear mixed models summaries as HTML table The sjt.lmer function ... [Read more...]

Introduction I recently had the opportunity to use Padé approximants. There is a lot of good information available on line on the theory and applications of using Padé approximants, but I had trouble finding a good example explaining just how to calculate the co-efficients. Basic Background Hearken back to undergraduate ... [Read more...]

by Joseph Rickert The R/Finance 2015 Conference wrapped up last Saturday at UIC. It has been seven years already, but R/Finance still has the magic! - mostly very high quality presentations and the opportunity to interact and talk shop with some of the most accomplished R developers, financial modelers ... [Read more...]