As a biostatistics student, I use R very frequently when analyzing data. At the same time, I interact with other researchers, some who know how to use R (R crowd) and some who don't (yet!): no-R crowd. This means that I have to be able to communicate my results to ...

<img src=' [Read more...]

I use Fuelly to track the fuel mileage in my Toyota Tundra pickup truck. They have a mobile app, so while I'm waiting for the truck to fill up, I log the odometer, and the number of gallons that I put in and then also the price per gallon of ...

Below are two functions for producing stacked area plots. The first is the more typical approach where sequential series are stacked on top of another (function: plot.stacked), while the second approach is the more aesthetically-oriented version called...

The ubiquitous LAPACK library provides several implementations for the singular-value decomposition (SVD). We will illustrate possible speed gains from using the divide-and-conquer method by comparing it to the base case.

<span>#include <RcppArmadillo.h></span>

<span>// [[Rcpp::depends(RcppArmadillo)]]</span>

<span>// [[Rcpp::export]]</span>
<span>arma</span><span>::</span><span>vec</span> <span>baseSVD</span><span>(</span><span>const</span> <span>arma</span><span>::</span><span>mat</span> <span>&</span> <span>X</span><span>)</span> <span>{</span>
    <span>arma</span><span>::</span><span>mat</span> <span>U</span><span>,</span> <span>V</span><span>;</span>
    <span>arma</span><span>::</span><span>vec</span> <span>S</span><span>;</span>
    <span>arma</span><span>::</span><span>svd</span><span>(</span><span>U</span><span>,</span> <span>S</span><span>,</span> <span>V</span><span>,</span> <span>X</span><span>,</span> <span>"standard"</span><span>);</span>
    <span>return</span> <span>S</span><span>;</span>
<span>}</span>

<span>// [[Rcpp::export]]</span>
<span>arma</span><span>::</span><span>vec</span> <span>dcSVD</span><span>(</span><span>const</span> <span>arma</span><span>::</span><span>mat</span> <span>&</span> <span>X</span><span>)</span> <span>{</span>
    <span>arma</span><span>::</span><span>mat</span> <span>U</span><span>,</span> <span>V</span><span>;</span>
    <span>arma</span><span>::</span><span>vec</span> <span>S</span><span>;</span>
    <span>arma</span><span>::</span><span>svd</span><span>(</span><span>U</span><span>,</span> <span>S</span><span>,</span> <span>V</span><span>,</span> <span>X</span><span>,</span> <span>"dc"</span><span>);</span>
    <span>return</span> <span>S</span><span>;</span>
<span>}</span>

Having the two implementations, which differ only in the method argument (added recently in Armadillo 3.930), we are ready to ...