JuliaGeometry / JuliaGeometry/CoordinateTransformations.jl
Unexpected output types from `inv(transform)(x)`
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- Dominant language
- Julia
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- 185
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Description
Consider the following
using CoordinateTransformations
using GeometryBasics
using LinearAlgebra
using Rotations
# define transformations
s = LinearMap(Diagonal(Vec3f(1,1,2)))
r = LinearMap(RotX(0.5f0 * π))
t = Translation(Vec3f(0,1,0))
srt = t ∘ r ∘ s
# vector to be transformed
p = Vec3f(1,2,3)
# display type of transformation output
@show typeof(s(p))
@show typeof(r(p))
@show typeof(t(p))
@show typeof(srt(p))
@show typeof(inv(s)(p))
@show typeof(inv(r)(p))
@show typeof(inv(t)(p))
@show typeof(inv(srt)(p))
I was expecting that the output types of all transformations above would be Vec{3, Float32}, but for the inverse transformations I see multiple different output types.
typeof(s(p)) = Vec{3, Float32}
typeof(r(p)) = Vec{3, Float32}
typeof(t(p)) = Vec{3, Float32}
typeof(srt(p)) = Vec{3, Float32}
typeof((inv(s))(p)) = StaticArrays.MVector{3, Float32}
typeof((inv(r))(p)) = Vec{3, Float32}
typeof((inv(t))(p)) = Vec{3, Float32}
typeof((inv(srt))(p)) = Vector{Float32}
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Research direction
Reproduce the reported behavior with the Julia snippet in the issue, focusing on the output types of the forward and inverse transformations. Compare the results for LinearMap, Rotations, Translation, and the composed transformation; done means the inverse behavior is understood and the inconsistent output types are addressed or documented.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- julia
- Domain
- computer-graphics
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 40/100