Window Representations

Multiple structs are used internally to model the constructive details and applicative rules for a Window over client data. All inherit from AbstractWindowing

abstract type AbstractWindow end

@kwdef mutable struct BasicWindow <: AbstractWindow const length::Int # span of contiguous elements

direct::Bool=true              # process from low indices to high

const onlywhole::Bool=true     # prohibit partial window
const drop_first::Bool=true    # omit results at start¹, if needed²
const drop_final::Bool=false   # omit results at finish¹, if needed²

end

@kwdef mutable struct Window{T} <: AbstractWindow const length::Int # span of contiguous elements

offset_first::Int=0            # start  at index offset_first + 1
offset_final::Int=0            # finish at index length - offset_final + 1

pad_first::Int=0               # pad with this many paddings at start
pad_final::Int=0               # pad with this many padding at end
const padding::T=nothing       # use this as the value with which to pad

const direct::Bool=true        # process from low indices to high

const onlywhole::Bool=true     # prohibit partial windows
const drop_first::Bool=true    # omit results at start¹, if needed²
const drop_final::Bool=false   # omit results at finish¹, if needed²

const trim_first::Bool=false   # use partial windowing over first elements, if needed
const trim_final::Bool=false   # use partial windowing over final elements, if needed

const fill_first::Bool=true    # a simpler, often faster alternative to trim
const fill_final::Bool=false   # a simpler, often faster alternative to trim

end

is indexing to be offset

notoffset(w::Window) = iszero(w.offsetfirst) && iszero(w.offsetfinal) isoffset(w::Window) = !notoffset(w)

>> specifying both a leading offset and a trailing offset is supported

is there to be padding

notpadded(w::Window) = iszero(w.padfirst) && iszero(w.padfinal) ispadded(w::Window) = !notpadded(w)

>> it is an error to specify both a leading padding and a trailing padding

is the information processed in direct (lower index to higher index) order

isdirect(w::Window) = w.direct

are only complete window spans to be allowed

onlywhole(w::Window) = w.onlywhole allowpartial(w::Window) = !onlywhole(w)

is dropping incomplete results expected

isdropping(w::Window) = (w.dropfirst ⊻ w.dropfinal) notdropping(w::Window) = !isdropping(w)

>> it is an error to select bothdropfirst anddropfinal

is trimmed windowing to be allowed

maytrim(w::Window) = allowspartials(w) && (w.trimfirst ⊻ w.trimlast)

>> it is an error to select bothtrimfirst andtrimfinal

>> it is an error to select eithertrim and select anyfill

is filled windowing to be allowed

mayfill(w::Window) = allowspartials(w) && (w.fillfirst ⊻ w.filllast)

>> it is an error to select bothfillfirst andfillfinal

>> it is an error to select eitherfill and select anytrim

@kwdef mutable struct WeightedWindow{Pad,F,T} <: AbstractWindow window::Window{Pad} # struct annotated above weightfun::F=nothing # a function that yields the weights weighting::Vector{T} # the weights collected end

the weight function is optional

if you specify a weight function, theweighting will be autogenerated

>> weightings are checked to ensure they sum to 1

¹ "at start"  is from the lowest  indices wheredirect == true
              is from the highest indices wheredirect == false

  "at finish" is from the highest indices wheredirect == true
              is from the lowest  indices wheredirect == false

² "if needed" is true if and only ifonlywhole == true and
             !iszero(rem(data_length, window_length))