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One interesting thing about quaternions that’s almost never mentioned anywhere on the internets, there’re two conventions for them. The convention in that arti
by Const-me 5y ago
One interesting thing about quaternions that’s almost never mentioned anywhere on the internets, there’re two conventions for them.
The convention in that article is known as “Hamilton's quaternions”. There’s another incompatible one usually called “JPL quaternions”, for some American Jet Propulsion Laboratory.
Authors of 99% articles about the quaternions, and software libraries implementing quaternions, are assuming exactly one of these conventions, and almost never mention which one that is.
More info there: https://fzheng.me/2017/11/12/quaternion_conventions_en/ https://fzheng.me/2017/11/12/quaternion_conventions_en/
- fault1 5y agoyou also see the variations from the group structure; https://en.wikipedia.org/wiki/Quaternion_group https://en.wikipedia.org/wiki/Quaternion_group
- billforsternz 5y agoI remember reading some library quaternion code (sorry can't remember which library) that started out with a lovely quote from Hamilton on how the idea burst into his mind in a flash as he walked with his wife near the river Liffey I think it was in Dublin. So I guess they mentioned it, at least indirectly.
- thermistokles 5y agoThere are actually even more. You can actually have 12 different variations depending on certain choices. Though the other sources of differences are minor. https://arxiv.org/abs/1711.02508 https://arxiv.org/abs/1711.02508 This is actually a great source of frustration in the robotics state estimation community, as you have the influential University of Minnesota using JPL, and most other universities using Hamiltonian.