• [Erice Weisstein's World of Mathematics]
  • [Euler angles] and [Rotation Matrices]
  • That funny 'star matrix' thing appears [here].
  • Euler's rotation theorem: only three parameters needed to a finite rotation about an axis. Using [quaternions] to represent [Euler parameters].
  • I have to invert a matrix. No, it's not a primitive operation in uBLAS. Involves determinants and cofactors and minors of matrices. Whee.
    • [Here] is everything I could possibly want to know about determinants.
• [Physics 211 Intermediate Mechanics] lecture notes by Prof. David Boal. Some good stuff in here on inertia tensors, Lectures 23 ff.
• Definition of [outer product of two vectors]. Also need to look [here] for terminology. It appears that 'cross product' may be a special (3d) case of 'outer product'.
• [What Every Computer Scientist Should Know About Floating-Point Arithmetic] Also available in [PDF] format. Weighs in at a hefty 94 pages.
• A nice [FAQ] on rotations, including quaternions.

Hmm... Geometric Algebra. Wish I had time to fully grok this. "It contains, in a fully integrated manner, linear algebra, vector calculus, differential geometry, complex number and quaternions as real geometric entities, and lots more. This powerful language is based in Clifford algebra."

• [Geometric Algebra of Spacetime]
• [Index] including pointers to software.
• [U of Cambridge]
• [Introductions to Geometric Algebra]
• [Honing Geometric Algebra for its use in the Computer Sciences]
• [Jaap Suter's] page at flipCode. Jaap recently proposed the addition of a Geometric Algebra library to Boost.
• C++ libraries
  • [CLU] Licensing unclear -- GPL or LGPL?
  • [Gaigen] Much different approach, claims to be far faster than CLU. Licensing for commercial use requires contacting author.
• [Maths for (Games) Programmers], by Ian Bell of Elite fame. Note the wry comment regarding Web publishing profitability.
  • FYI, there's a (somewhat) interesting story behind Elite. The two responsible for the game are David Brabben and Ian Bell. Brabben went on to milk Elite for all it was worth (lots of sequels - a couple of which had questionable quality). Brabben got (moderately) rich - Bell didn't. Bell wanted to give stuff away and make it a lot more available but Brabben didn't. Various lawsuits ensued and bad blood still exists between the two. Just thought you might be interested for when we become rich through SDx. JDH
• An interesting [home page], see articles.