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Achllle / dual_quaternions_ros

Dual Quaternion conversions from/to ROS messages
MIT License
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Clarify inverse / add mathematical inverse #35

Closed Achllle closed 4 years ago

Achllle commented 4 years ago

The formula for the inverse of a not necessarily unit DQ is

Inv(a +eb) = inv(a) (1 - eb inv(a)) # a != 0

, not sure if we need to replace the current formulation or have a separate formulation

Achllle commented 4 years ago

This is the correct formulation: If you work it out, you get the same

sigma = p + eps * q
inv(sigma) = inv(p) - eps * inv(p) * q * inv(p)

which is the same as the code