I took a Coursera course this summer on linear algebra which showed how to compute this in one of the labs. It gives you a data file with each of the votes of

I took a Coursera course this summer on linear algebra which showed how to compute this in one of the labs. It gives you a data file with each of the votes of each of the senators in the 109th congress, and you use vectors and dot product for determining most/least similar voting, mean dem/repub voting, bitter rivals, and whether John McCain is really a maverick. This was probably one of the most fun labs in any course I've ever taken. The course materials are still online: https://spark-public.s3.amazonaws.com/matrix/politics_lab.zip https://spark-public.s3.amazonaws.com/matrix/politics_lab.zi... EDIT: Forgot to mention the course material is all in python. It's worth checking out.