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Is there any way to minimize Number of routes in solomon instances?


#1

Hi everyone,
I’ve tried everything to minimize the number of vehicles in Solomon instances, especially random one.
By adding fixed vehicle cost, fixing the number of vehicles, adding additional jobs remove strategies (routeRemoval).
I believe I need to change somethings in the insertion strategy, but I don’t know where?
Does Anyone have any other idea to minimize them?
Thank you.


#2

Hi @anasstaha19,

We had a discussion on reducing the number of vehicles earlier. Unfortunately we have not yet come to a good solution.

I am quite interested in your routeRemoval strategy. Could you please elaborate? Thanks.

Best regards,
He


#3

I was more or less successful by successively reducing the number of available vehicles. If your read this Schrimpf publication, they add a penalty for additional vehicles. This did not work for me quite well (maybe I just had not understood how they did it). For some instances where time windows were too tight I just could not find the best number of vehicles which was frustating by the way. I guess this might be tackled with a ruin strategy that takes time window into account more reasonably, i.e. something like radial ruin with another definition of neighborhood, e.g. two jobs are neighbors if they are accessible within the defined time windows and if so they are located closer to each other if distance between them is small or similar.