Custom collection types

mutable struct CacheIndexDict{K, KeyRange<:AbstractUnitRange{K}, V} <: RigidBodyDynamics.CustomCollections.AbstractIndexDict{K,V}

Like IndexDict, but contains an additional Bool dirty bit to be used in algorithms involving cached data.

An immutable AbstractDict for which the value is the same, no matter what the key is.

struct ConstVector{T} <: AbstractArray{T,1}

An immutable AbstractVector for which all elements are the same, represented compactly and as a bitstype if the element type is a bitstype.

struct IndexDict{K, KeyRange<:AbstractUnitRange{K}, V} <: RigidBodyDynamics.CustomCollections.AbstractIndexDict{K,V}

An associative type whose keys are an AbstractUnitRange, and whose values are stored in a Vector. IndexDict is an ordered associative collection, with the order determined by key range. The nature of the keys enables very fast lookups and stores.

Examples

julia> IndexDict(2 : 4, [4, 5, 6])
RigidBodyDynamics.CustomCollections.IndexDict{Int64,UnitRange{Int64},Int64} with 3 entries:
  2 => 4
  3 => 5
  4 => 6

julia> IndexDict{Int32, UnitRange{Int32}}(i => 3 * i for i in Int32[4, 2, 3])
RigidBodyDynamics.CustomCollections.IndexDict{Int32,UnitRange{Int32},Int64} with 3 entries:
  2 => 6
  3 => 9
  4 => 12

struct NullDict{K, V} <: AbstractDict{K,V}

An immutable associative type that signifies an empty dictionary and does not allocate any memory.

struct SegmentedBlockDiagonalMatrix{T, M<:AbstractArray{T,2}} <: AbstractArray{T,2}

SegmentedBlockDiagonalMatrix is an AbstractMatrix backed by a parent AbstractMatrix, which additionally stores a sequence of views into the diagonal blocks of the parent matrix. This type is useful for storing and updating block-diagonal matrices whose block contents may change but whose overall structure is fixed, such as configuration derivative <-> velocity jacobians.

struct SegmentedVector{K, T, KeyRange<:AbstractRange{K}, P<:AbstractArray{T,1}} <: AbstractArray{T,1}

SegmentedVector is an AbstractVector backed by another AbstractVector (its parent), which additionally stores an IndexDict containing views into the parent. Together, these views cover the parent.

Examples

julia> x = [1., 2., 3., 4.]
4-element Array{Float64,1}:
 1.0
 2.0
 3.0
 4.0

julia> viewlength(i) = 2
viewlength (generic function with 1 method)

julia> xseg = SegmentedVector{Int}(x, 1 : 2, viewlength)
4-element RigidBodyDynamics.CustomCollections.SegmentedVector{Int64,Float64,Base.OneTo{Int64},Array{Float64,1}}:
 1.0
 2.0
 3.0
 4.0

julia> segments(xseg)[1]
2-element SubArray{Float64,1,Array{Float64,1},Tuple{UnitRange{Int64}},true}:
 1.0
 2.0

julia> yseg = similar(xseg, Int32); yseg .= 1 : 4 # same view ranges, different element type
4-element RigidBodyDynamics.CustomCollections.SegmentedVector{Int64,Int32,Base.OneTo{Int64},Array{Int32,1}}:
 1
 2
 3
 4

julia> segments(yseg)[2]
2-element SubArray{Int32,1,Array{Int32,1},Tuple{UnitRange{Int64}},true}:
 3
 4