Posts

subscribe via RSS

  • Automatically Check if R Package is the Latest Version on Package Load

    Intro Recently, I’ve had to think about a lot of things as it relates to simplifying the R experience. Specifically, how do you ease engineers, who are fluent in MATLAB, into working with R? As part of this brainstorming session, I’ve stumbled upon quite a few important realizations. One of these realizations is that there is clear lack of indication as to whether or not a loaded package is up-to-date. That is, when a package...

    Read more...
  • R Data Packages in External Data Repositories using the Additional_repositories field

    Intro In the prior series entry on data packages, there was a discussion about how to create an R data package. Within the final entry in the series, the goal is to address the unthinkable: a data packages rejected from CRAN. Rejected data packages are particularly problematic as they show up as a missing dependency on the statistical methodology package under R CMD check. Fear not though, one can still use the data package that...

    Read more...
  • Creating an R Data Package

    Intro In the previous entry, there was a discussion regarding CRAN’s R package policy, specifically on the size of R data packages. Within this post, the aim is to address the best way to create a data package that is able to be distributed via CRAN. To do so, we reflect upon different methods used to construct a data package on CRAN. The next entry deals with constructing an external repository when the size of...

    Read more...
  • Size and Limitations of Packages on CRAN

    Intro This is the first entry out of three writings to address the nature of Data Packages within the R ecosystem. Within this post, we’ll talk about R package guidelines, distribution of a package, and the amount of data that is able to be shipped. In the next entry, the focus is on the best ways to create an R data package. For the third and final entry, the discussion turns to the creation of...

    Read more...
  • R Compiler Tools for Rcpp on OS X

    Intro The objective behind this post is to provide users with information on how to associate a compiler with the OS X version of R. This has been a bit problematic for many R users since OS X Mavericks, which resulted in gfortran binaries being dropped from the R installer. More curiously, the additional demand to have access to a compiler vs. downloading a binary from CRAN became apparent slightly after Rcpp’s 0.10.0 version, when...

    Read more...
  • Differences in Primitive Data Types between OS X and Windows

    Intro A while ago, I was given a binary file reading script written using MATLAB. The scripts goal was to read a binary output file from an Inertial Measurement Unit (IMU) into a MATLAB matrix. What I worked on was converting the code from MATLAB to C++, specifically for use with the Armadillo C++ Matrix Library. Furthermore, I wanted to embed it within the gmwm R package that provides a method for modeling IMU error...

    Read more...
  • Proofs of the Gamma Distribution

    Intro Within this post, I’ll explore the properties of the Gamma distribution. The results presented here are interesting as they ripple throughout mathematical statistics. Each result has a proof associated with it in hopes of better how the result came to be. Below is a preview of the posts contents. Gamma in real life Parameterizations of Gamma Definition 1: $X \sim Gamma\left({\alpha,\beta}\right), \quad f\left( x \right) = \frac{1}{ {\Gamma \left( \alpha \right){\theta ^\alpha } }...

    Read more...
  • cIRT

    Project Details Project Title: Choice Item Response Theory (cIRT) Project URL: http://cran.r-project.org/web/packages/cIRT/ Code Repository: https://github.com/tmsalab/cIRT Project Paper: http://link.springer.com/article/10.1007%2Fs11336-015-9484-7 Project Version: 1.1.0 Project Status: Frozen Project Description: Jointly model the accuracy of cognitive responses and item choices within a bayesian hierarchical framework as described by Culpepper and Balamuta (2015) <doi:10.1007/s11336-015-9484-7>. In addition, the package contains the datasets used within the analysis of the paper. Features Highlights C++ Implementation of the hierarchial modeling framework for choice Three...

    Read more...
  • gmwm

    Project Details Project Title: Generalized Method of Wavelet Moments (GMWM) Project URL: http://cran.r-project.org/web/packages/gmwm/ Code Repository: https://github.com/SMAC-Group/gmwm Project Version: 1.0.0 Project Status: Active Project Description: Generalized Method of Wavelet Moments (GMWM) is an estimation technique for the parameters of time series models. It uses the wavelet variance in a moment matching approach that makes it particularly suitable for the estimation of certain state-space models. Furthermore, there exists a robust implementation of GMWM, which allows the robust...

    Read more...
  • Sum of Squares Manipulations

    Intro Simple Linear Regression (SLR) has been tickled to death. One interesting tidbit about SLR is that of the different Sum of Squares formulations that exist and how they tie into just about everything. This posts tries to deconstruct the sum of squares formulations into alternative equations. Definitions In the least technical terms possible…. Sum of Squares provides a measurement of the total variability of a data set by squaring each point and then summing...

    Read more...