New version for chunks #94

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1. JulStraus commented on Jun 5, 2026

   

   JulStraus

   on Jun 5, 2026

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   Additional thought: It would also be possible to consider varying durations for the individual chunks, although this makes it obviously a bit more difficult.
2. trulsf commented on Jun 8, 2026

   

   trulsf

   on Jun 8, 2026

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   I think it is a good idea - at least if we have the use cases. The first version is to some extent already covered by Iterators.partition:

   ts = TwoLevel(2,1, SimpleTimes([1, 2, 3, 6, 1, 1, 1, 1, 1, 1]))
   t_inv = first(strategic_periods(ts))
   
   parts = collect(Iterators.partition(t_inv, 3))
   # Returning
   [sp1-t1, sp1-t2, sp1-t3]
   [sp1-t4, sp1-t5, sp1-t6]
   [sp1-t7, sp1-t8, sp1-t9]
   [sp1-t10]

   Note that partition is eager and returns the full vector of periods for each set in the partition. If we follow that convention, the implementation would avoid the length(collect(...)) in the state for a duration-based version:

   struct PartitionDuration{I}
       itr::I
       duration::TimeStruct.Duration
   end
   
   partition_duration(itr, dur) = PartitionDuration(itr, dur)
   Base.IteratorSize(::Type{<:PartitionDuration})   = Base.SizeUnknown()
   Base.IteratorEltype(::Type{PartitionDuration{I}}) where {I} = Base.HasEltype()
   Base.eltype(::Type{PartitionDuration{I}}) where {I} = Vector{eltype(I)}
   
   struct IterationCutShort end
   
   function Base.iterate(w::PartitionDuration, state = nothing)
       state isa IterationCutShort && return nothing
       y = isnothing(state) ? iterate(w.itr) : iterate(w.itr, state)
       isnothing(y) && return nothing
       chunk = eltype(w.itr)[]
       acc = zero(w.duration)
       while true
           push!(chunk, y[1])
           acc += TimeStruct.duration(y[1])
           acc >= w.duration && return chunk, y[2]
           nxt = iterate(w.itr, y[2])
           isnothing(nxt) && return chunk, IterationCutShort()
           y = nxt
       end
   end

   This will give similar results as above (although with vectors):

   julia> pd = [p for p in partition_duration(t_inv, 6)]
   3-element Vector{Vector{TimeStruct.OperationalPeriod{TimeStruct.SimplePeriod{Int64}}}}:
    [sp1-t1, sp1-t2, sp1-t3]
    [sp1-t4]
    [sp1-t5, sp1-t6, sp1-t7, sp1-t8, sp1-t9, sp1-t10]
3. JulStraus

   added the

   Feature

   issue type on Jun 9, 2026
4. JulStraus

   added

   enhancementNew feature or requestNew feature or request

   on Jun 9, 2026
5. JulStraus commented on Jun 9, 2026

   

   JulStraus

   on Jun 9, 2026

   Last edited by JulStraus

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   I personally think it is fine that it returns a vector, although it might be beneficial to have a type for indexing variables over the partitions as it can make things easier. One approach could be:

   struct PartitionDuration{T}
       part::Int
       per::Vector{T}
   end
   
   Base.iterate(pd::PartitionDuration, state = nothing) = iterate(pd.per, state)
   Base.show(io::IO, pd::PartitionDuration) = print(io, "part-$(pd.part)")

   For this, I adjusted the Base.iterate function a bit, including cleaning it up to avoid while true:

   function Base.iterate(w::PartitionDurationIterator, state = (nothing, 1))
       isa(state[1], Iterators.IterationCutShort) && return nothing
       y = iterate(w.itr, state[1])
       isnothing(y) && return nothing
       part = state[2]
       chunk = eltype(w.itr)[]
       acc = zero(w.duration)
       while !isnothing(y)
           push!(chunk, y[1])
           acc += duration(y[1])
           acc >= w.duration && break
           y = iterate(w.itr, y[2])
       end
       isnothing(y) && return PartitionDuration(part, chunk), (Iterators.IterationCutShort(), part+1)
       return PartitionDuration(part, chunk), (y[2], part+1)
   end

   The aim of the adjustments was to reduce the number of exits from the function.

   One thing which is still important is to decide what inforation should be included in PartitionDuration. It could be beneficial to include as well, if that is the case, the information of the TimePeriods.
6. JulStraus

   self-assigned this

   on Jun 9, 2026
7. JulStraus

   closed this as completedin #99on Jun 24, 2026