Release 0.8.0

[N-Wouda]

Stub for 0.8.0 release notes

PyVRP 0.8.0

New features

• The Model interface now supports printing solver progress through the display argument on Model.solve (in Print solver progress #460).
• PyVRP now also supports return shipments, from clients back to the depot (in Simultaneous pickup and delivery #471). This means PyVRP can now also solve the VRP with backhaul, and the VRP with simultaneous pickup and delivery. Examples have been added to the documentation (in Update quick tutorial with new problem variants #513).
• Add support for a maximum distance constraint #500
• Generalised VRP #514

Breaking changes

• The interface of the repair operators in pyvrp.repair was updated to work exclusively on route lists (in Update pyvrp.repair operator interface to use lists of routes, not solutions #448).
• The pyvrp.search.Route.fixed_cost member function has been renamed to fixed_vehicle_cost (in Consistency checks #450). This should not affect a lot of downstream code since this class is mostly internal to the search routines.
• The default values for tw_late and max_duration has changed to INT_MAX in all cases. Additionally, VehicleType.tw_early = 0, VehicleType.tw_late = INT_MAX, and VehicleType.max_duration = INT_MAX now no longer take None as an argument (in Make [0, INT_MAX] the default time windows #463).
• The Client.demand attribute has been renamed to delivery, and a Client.pickup attribute has been added. The Client.__init__ method has been updated to reflect these changes (in Simultaneous pickup and delivery #471). More generally, demand has been renamed to delivery, and a pickup value has been added where appropriate.
• We have separated the underlying data structures for clients and depots (in Separate client and depot structs #481). Before, a depot also used the same data structure as a client, which resulted in many attributes that a depot does not have (and should not have been set to values other than zero). This change rectifies the situation by making those attributes unavailable for depots. The consequences to user code should be limited if one uses the pyvrp.Model interface.
• Remove "get" prefix from data accessors #499
• Add support for a maximum distance constraint #500
• Split 2-OPT into ReverseSegment and SwapTails #510
• Add support for a maximum distance constraint #500
• Make name argument keyword only #526

Additional

• We have added OR-Tools as a reference solver to our benchmarks page (in OR-Tools benchmark #469). The gaps to the BKS are 5-13% across different instances.
• The TimeWindowSegment has been renamed to DurationSegment. Although technically a breaking change, this class is not part of the public API, and the change should thus not affect user code (in Rename TimeWindowSegment to DurationSegment #483).
• The read() function now also applies the round_func argument to any pickup, delivery, and capacity data (in Update read and tests to properly round load and capacity values #493).
• PyVRP now uses 64-bit integer values internally (in Switch over to int64_t #490). This significantly increases the range of acceptable input values.

Bugs fixed

[N-Wouda]

@leonlan @wouterkool feel free to add to these stubs as we merge PRs. I'll use this as a basis for the change notes in the eventual release.

[N-Wouda]

TODO: check commit history for updates I missed.

[N-Wouda]

I think we're basically done with 0.8.0 now. If #534 works well we can merge that in and coin a new release.

[N-Wouda]

@leonlan shall we release 0.8.0 based off of ce0563a? If we can benchmark that version I'll update the version number on main and draft the release notes.