## Sundry Links for December 6, 2014

Sketching as a Tool for Numerical Linear Algebra: A neat paper on sketching algorithms for linear algebra. No, not that kind of sketching. “One first compresses it to a much smaller matrix by multiplying it by a (usually) random matrix with certain properties. Much of the expensive computation can then be performed on the smaller matrix, thereby accelerating the solution for the original problem.”

Maps and the Geospatial Revolution: Coursera is teaching a class in the spring on how geospatical technology has changed our world.

Geoprocessing with Python using Open Source GIS: Speaking of geospatial technology, here are some slides and problems from a class on “Geoprocessing with Python”.

How to use the bash command line history: Bash’s history can do more than I realized!

A geometric interpretation of the covariance matrix: Superb little post explaning covariance matrices with pictures and geometry.