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Remove norm field in Quaternion #243

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Merged
merged 5 commits into from
Jan 3, 2023
Merged

Remove norm field in Quaternion #243

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a47eaa4
remove .norm field in Quaternion
hyrodium Oct 26, 2022
9375f14
update constructors of QuatRotation
hyrodium Dec 29, 2022
87d9b96
update unittest on QuatRotation
hyrodium Dec 29, 2022
a6902a0
avoid unnecessary normalizations in QuatRotation
hyrodium Dec 29, 2022
c5cae5b
remove _normalize(::QuatRotation)
hyrodium Dec 30, 2022
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3 changes: 2 additions & 1 deletion src/rand.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -66,5 +66,6 @@ end
end

function Random.rand(rng::AbstractRNG, ::Random.SamplerType{<:QuatRotation{T}}) where T
_normalize(QuatRotation{T}(randn(rng,T), randn(rng,T), randn(rng,T), randn(rng,T)))
q = Quaternion(randn(rng,T), randn(rng,T), randn(rng,T), randn(rng,T))
return QuatRotation{T}(sign(q))
end
48 changes: 15 additions & 33 deletions src/unitquaternion.jl
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Expand Up @@ -11,29 +11,19 @@ Follows the Hamilton convention for quaternions.
QuatRotation(w,x,y,z)
QuatRotation(q::AbstractVector)
```
where `w` is the scalar (real) part, `x`,`y`, and `z` are the vector (imaginary) part,
where `w` is the scalar (real) part, `x`, `y`, and `z` are the vector (imaginary) part,
and `q = [w,x,y,z]`.
"""
struct QuatRotation{T} <: Rotation{3,T}
q::Quaternion{T}

@inline function QuatRotation{T}(w, x, y, z, normalize::Bool = true) where T
@inline function QuatRotation{T}(q::Quaternion, normalize::Bool = true) where T
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@mikmoore mikmoore Nov 11, 2022

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This appears to be missing a check for iszero(q) (on either the input or output - undecided), which should probably result in an error. I'd be willing to permit !isfinite(q) to pass (the result will presumably be a NaN quaternion) but someone may prefer that errors as well.

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@hyrodium hyrodium Dec 29, 2022

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The current behavior of constructors other than the Quaternion is also not checked for input correctness, so I would like to separate the feature into another PR.

julia> AngleAxis(0.0, 0.0, 0.0, 0.0)
3×3 AngleAxis{Float64} with indices SOneTo(3)×SOneTo(3)(0.0, NaN, NaN, NaN):
 NaN  NaN  NaN
 NaN  NaN  NaN
 NaN  NaN  NaN

julia> QuatRotation(0.0, 0.0, 0.0, 0.0)
3×3 QuatRotation{Float64} with indices SOneTo(3)×SOneTo(3)(QuaternionF64(0.0, 0.0, 0.0, 0.0)):
 0.0  0.0  0.0
 0.0  0.0  0.0
 0.0  0.0  0.0

julia> RotMatrix{3}([1 1 1;2 2 2;3 3 3])
3×3 RotMatrix3{Int64} with indices SOneTo(3)×SOneTo(3):
 1  1  1
 2  2  2
 3  3  3

if normalize
inorm = inv(sqrt(w*w + x*x + y*y + z*z))
new{T}(Quaternion(w*inorm, x*inorm, y*inorm, z*inorm, true))
new{T}(sign(q))
else
new{T}(Quaternion(w, x, y, z, true))
end
end

@inline function QuatRotation{T}(q::Quaternion) where T
if q.norm
new{T}(q)
else
throw(InexactError(nameof(T), T, q))
end
end
QuatRotation{T}(q::QuatRotation) where T = new{T}(q.q)
end

function Base.getproperty(q::QuatRotation, f::Symbol)
Expand All @@ -52,17 +42,16 @@ end

# ~~~~~~~~~~~~~~~ Constructors ~~~~~~~~~~~~~~~ #
# Use default map
function QuatRotation{T}(w,x,y,z, normalize::Bool = true) where T
QuatRotation{T}(Quaternion(w,x,y,z), normalize)
end
function QuatRotation(w,x,y,z, normalize::Bool = true)
types = promote(w,x,y,z)
QuatRotation{eltype(types)}(w,x,y,z, normalize)
QuatRotation{float(eltype(types))}(w,x,y,z, normalize)
end

function QuatRotation(q::T) where T<:Quaternion
if q.norm
return QuatRotation(real(q), imag_part(q)..., false)
else
throw(InexactError(nameof(T), T, q))
end
function QuatRotation(q::Quaternion{T}, normalize::Bool = true) where T<:Real
return QuatRotation{float(T)}(q, normalize)
end

function Quaternions.Quaternion(q::QuatRotation)
Expand All @@ -84,6 +73,7 @@ end

# Copy constructors
QuatRotation(q::QuatRotation) = q
QuatRotation{T}(q::QuatRotation) where T = QuatRotation{T}(q.q)

# QuatRotation <=> Quat
# (::Type{Q})(q::Quat) where Q <: QuatRotation = Q(q.w, q.x, q.y, q.z, false)
Expand Down Expand Up @@ -233,21 +223,13 @@ Rotations.params(p) == @SVector [1.0, 2.0, 3.0] # true
@inline params(q::QuatRotation) = SVector{4}(real(q.q), imag_part(q.q)...)

# ~~~~~~~~~~~~~~~ Initializers ~~~~~~~~~~~~~~~ #
@inline Base.one(::Type{Q}) where Q <: QuatRotation = Q(1.0, 0.0, 0.0, 0.0)
@inline Base.one(::Type{Q}) where Q <: QuatRotation = Q(1.0, 0.0, 0.0, 0.0, false)


# ~~~~~~~~~~~~~~~ Math Operations ~~~~~~~~~~~~~~~ #

# Inverses
Base.inv(q::Q) where Q <: QuatRotation = Q(conj(q.q))

function _normalize(q::Q) where Q <: QuatRotation
w = real(q.q)
x, y, z = imag_part(q.q)

n = norm(params(q))
Q(w/n, x/n, y/n, z/n)
end
Base.inv(q::Q) where Q <: QuatRotation = Q(conj(q.q), false)

# Identity
(::Type{Q})(I::UniformScaling) where Q <: QuatRotation = one(Q)
Expand All @@ -261,11 +243,11 @@ Create a `Quaternion` with zero scalar part (i.e. `q.q.s == 0`).
"""
function pure_quaternion(v::AbstractVector)
check_length(v, 3)
Quaternion(zero(eltype(v)), v[1], v[2], v[3], false)
Quaternion(zero(eltype(v)), v[1], v[2], v[3])
end

@inline pure_quaternion(x::Real, y::Real, z::Real) =
Quaternion(zero(x), x, y, z, false)
Quaternion(zero(x), x, y, z)

function expm(ϕ::AbstractVector)
check_length(ϕ, 3)
Expand Down Expand Up @@ -309,7 +291,7 @@ rmult(w) * SVector(q)
Sets the output mapping equal to the mapping of `w`
"""
function Base.:*(q1::QuatRotation, q2::QuatRotation)
return QuatRotation(q1.q*q2.q)
return QuatRotation(q1.q * q2.q, false)
end

"""
Expand Down
2 changes: 1 addition & 1 deletion test/unitquat.jl
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Expand Up @@ -14,7 +14,7 @@ import Rotations: vmat, rmult, lmult, hmat, tmat
@test QuatRotation(1.0, 0.0, 0.0, 0.0) isa QuatRotation{Float64}
@test QuatRotation(1.0, 0, 0, 0) isa QuatRotation{Float64}
@test QuatRotation(1.0, 0, 0, 0) isa QuatRotation{Float64}
@test QuatRotation(1, 0, 0, 0) isa QuatRotation{Int}
@test QuatRotation(1, 0, 0, 0) isa QuatRotation{Float64}
@test QuatRotation(1.0f0, 0, 0, 0) isa QuatRotation{Float32}

q = normalize(@SVector rand(4))
Expand Down