A measure of perturbed central tendency


  • The Statistician's Apprentice: An Introduction to the SWP Operator


    The sweep operator as defined in (Dempster, 1969), commonly referred to as the SWP operator, is a useful tool for a computational statistician working with covariance matrices. In particular, the SWP operator allows a statistician to quickly regress all variables against one specified variable, obtaining OLS estimates for regression coefficients and variances in a single application. Subsequent applications of the SWP operator allows for regressing against more variables.



  • meanShiftR


    In this blog post, I will be introducing the meanShiftR package. meanShiftR is a rewrite of my original mean shift R package from 2013, based on the Fast Library for Approximate Nearest Neighbors (FLANN). The meanShiftR package is focused on providing to R users the most computationally efficient mean shift implementations available in the literature. This includes approximations to the mean shift algorithm through kernel truncations and approximate nearest-neighbor (ANN) approaches.



  • Elizabeth!


    Over the last few months I have been spending my nights taking care of my newly born second daughter. Keeping me company during the sleepless wee hours of the morning was the Reconcilable Differences Podcast. In episode 17 of this podcast, It's Devastating, there was an open question placed by John Siracusa with regard to how baby names change over time, and if there were any sudden changes. In this blog post, part of my investigation of podcast theme series, I will take a look at these two questions. I will also provide my source code in the spirit of reproducible research.



  • Kernels for everyone!


    During my dissertation, I spent a lot of time working on spatial kernel estimates. Where spatial kernel estimates are defined as a convolution of a spatial suppport ,

    A simple example of this estimate is a Gaussian filter or blur in more common parlance. In the Guassian filter, is the normal density function , with the location parameter and scale parameter equal to the bandwidth .



  • On a finite time scale


    It was rumored that updates to the MacBook Pro were coming at WWDC. These rumors did not pan out. Instead it looks like the new MacBook Pro will be landing sometime later this year, possibly due to delays in availability of high end Skylake 45w mobile parts. This seems plausible, given that Intel only released its Skylake quad core NUC in mid-May. The magnitude of these delays has certainly made its way around the tech press, but are these delays really exceptional?



  • Predicting Agriculture, Poorly (Part I)


    Crop rotation is an agricultural production practice to increase yield, mitigate disease, and control pests. This production practice involves growing crops in specific sequences to improve the quality of soil for the following crop. A common example in the United States is the practice of growing soybeans before corn. In this example soybeans fixate nitrogen in the soil leading to an increase in yield and reduction in fertilizer consumption.



  • The cdlTools R package


    This is a brief tutorial on the cdlTools package developed by Lu Chen and I to download and perform some simple analysis on USDA's cropland data layer (CDL). This tutorial will cover downloading CDL data, obtaining some zonal statistics, and explore land cover change. This package is not currently available on CRAN, but is available via github, and can be installed through Hadley Wickham's devtools package.