haying/madlib — comment on commit 007ff442bbcedbec7c735f0fc0727904e33c0bc5
File: src/modules/igd/logistic_igd.cpp line 240
By fschopp:

I see. Actually, in the long term I would like to abstract away from sparse/dense implementation details as much as possible, and define a new C++ and SQL type instead.

Incidentally, we already have a sparse-vector type on the SQL side (see the MADlib svec module), but it is currently run-length encoded and there is no correspondence on the C++ side.

One option to use on the C++ side is Eigen: http://eigen.tuxfamily.org/api/TutorialSparse.html
I have already integrated the dense part of Eigen into the C++ abstraction layer, with very good results so far (see the "template" branch in my fork).