Today in 1843 William Rowan Hamilton invented quaternions (a way of using 4-dimensional numbers to concisely encode 3-dimensional positions) as he walked across Brougham Bridge in Dublin, carving them into the stone there to make sure he didn’t forget later. Begorah, that’s 132 years ago!
http://en.wikipedia.org/wiki/Quaternions
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An anniversary worth celebrating. As I recall from when I encountered them in the late 70's as a new grad working on the space shuttle simulator, they came back into fashion with computer graphics, and one can do rotations with fewer floating point calculations than with rotation matrices.
ReplyDeleteBut I'm a bit confused on encoding 3 dimensional position: aren't three coordinates are adequate to describe a position? A quaternion can efficiently describe both a position AND orientation. Am I remembering correctly or have I missed something?
You're right. What I wrote here was much abbreviated (cross-posted on my Facebook page where none of my acquaintances would think about that gap).
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