This library is just a fairly short library to demonstrate a research paper, so I release it in to the public domain, with the disclaimer that I assume no responsibility for its use and make no guarantees about it whatsoever.

If you find it helpful, of course it would be nice of you to cite the relevant paper ("Type-Constrained Direct Fitting of Quadric Surfaces").

Note that this library is distributed with (and relies on) a few other free/open source libraries that may have their own licenses -- specifically, I use:

 - "graphics gems" code (algebra3.h and roots3and4.cpp)
http://tog.acm.org/resources/GraphicsGems/

 - TNT/JAMA libraries
http://math.nist.gov/tnt/download.html

 - the CLAPACK & CBLAS libraries; see http://www.netlib.org/lapack/LICENSE.txt
http://www.netlib.org/clapack/faq.html#1.2
http://www.netlib.org/blas/faq.html#2

 - for the code in the "demo" folder I also use glfw:
http://www.glfw.org/license.html