[rules-users] [Optaplanner] Scheduling + VRP

[Geoffrey De Smet]

On 01-12-13 23:27, Mats Norén wrote:
> Thanks,
> I'll give number three a try :-)
> Is there an example with two planning entities?
Not yet. Also look for a recent question on this mailing list about 
Construction Heuristics and 2 planning entity classes.
There's a small undocumented part that that didn't make the 6.0.0.Final 
ref manual.
>
> Regards,
> Mats
>
> 1 dec 2013 kl. 10:58 skrev Geoffrey De Smet <ge0ffrey.spam at gmail.com>:
>
>> On 30-11-13 15:02, Mats Norén wrote:
>>> Hi,
>>> I'm looking for an example that does both scheduling and vrp.
>> No example of that combination yet.
>>> I have workers with certain skills and I have goods (which require a particular skill set) to be delivered or picked up within certain time windows.
>>> Each worker work in a team.
>>> The team should if possible be assigned to the same delivery/pickup.
>>> The workers work in shifts and by law has to have breaks etc.
>>> I want to create a schedule that assigns workers/teams to deliveries/pickups and stay within the time windows as well as optimizing the distance travelled.
>>> I thought about the nurse rostering example together with cvrptw but the nurse rostering uses shifts (day, night).
>>>
>>> Do I have to do it in two steps? First VRP and then try to assign the workers?
>> In practice, I often see this happening in 2 separate, sequential
>> planning problems (or phases),
>> but that's just because of Conway's law:
>>    "organizations which design systems ... are constrained to produce
>> designs which are copies of the communication structures of these
>> organizations"
>>
>> 2 phases is probably suboptimal, because the limitations on the second
>> phase influence the planning of the first phase.
>> There are 3 ways to handle that:
>>
>> 1) Ignore it that 2 phases is suboptimal. You 'll have better results
>> that the old system already. You can tweak it by adding some constraints
>> in phase 1 that make it easier for phase 2.
>>
>> 2) Bender's decomposition. Basically ping-pong between phase 1 and phase
>> 2 (where the result of phase 2 adds constraints in phase 1). Not yet
>> supported out-of-the-box by OptaPlanner, but probably a domain specific
>> pita to implement.
>>
>> 3) Do it all in 1 phase. OptaPlanner 6 has been written to handle
>> multiple planning entity classes and multiple planning variables, so
>> it's definitely possible. You 'll like need to add course grained moves
>> to get things to change for phase 1 in a way that works for phase 2, to
>> avoid getting stuck in a "score trap" (see docs).
>>
>> I am a strong believer in approach 3). If you go that way, let me know
>> how it works out: I need cases to prove that the human planners that
>> follow Conway's law should not limit our potential when automating this.
>> But the conservative choice is 1).
>>
>> In any case, I recommend to prototype phase 1 first.
>>
>>> The only hard facts are the workers worktime and the goods delivery/pickup time.
>>>
>>> Any suggestions?
>>>
>>> Best regards,
>>> Mats
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