statistics-related miscellany

contents and brief descriptions:

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1. clusters contains some simple code implemeting k-means clustering. using the Eigen C++ library. Hardly a hot new topic! Also provides a simple example of easy toggling between a standalone C(++) program and functioning as a callable from another language (in this case, R via Rcpp).

Compilation needs -std=c++11 or more recent and an include -I'path-to-eigen'. (and ensure that __using_Rcpp is defined or not, depending on the use case).

2. cdf2 is a (hopefully) efficient impementation of calculating and plotting a bivarate empirical cdf. The concept is not very profound, but the algorithm is kind of interesting, and could certainly be improved.