How to use OR tool for acheiving Capacitated Vehicle Routing Problem with more than 15 vehicle_capacity?

[reshma rabindranath]

I used python code provided in the below link 

https://github.com/google/or-tools/blob/master/examples/python/cvrptw.py for acheiving Capacitated Vehicle Routing Problem with Time Windows using OR tools.

For this  i used latitude and logitude as data["locations"].

For distance calculations,i used "The Haversine Formula" and "horizon" value as 1440.

same like latitude and logitude, i kept values for remaining keys as below.

  data["num_vehicles"] = 20

  data["vehicle_capacity"] = 15

  data["vehicle_speed"] = 5*60/3.6 # Travel speed: 5km/h to convert in m/min

  data["depot"] = 0

For data["demands"], if i use any of values more than 15 the program failed or hanged out.

seems like ["vehicle_capacity"] key is direct propotional to data["demands"] key.

 My vechicle capacity should be static value of 15, my expectation is when i kept as 15, it should be 2 routes or vehicles but actually what happened is program is not responding not even throwing exception.

[blind.line]

The demand is a single quantity. Like a big pallet of stuff all wrapped up in shrinkwrap. The solver doesn't have the common sense to break it up into chunks. So if a demand is 30, and vehicle max capacity is 15, no vehicle can accept that 30-sized load. 

Furthermore, if you want to manually break up 30 into chunks of 1 unit each, you will need to creat 30 "nodes" each at the same location with 1 unit of demand. The solver will visit each node at most one time. 

Hope that helps. 

James

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[reshma rabindranath]

Hai James, 

  

 Your logic worked for me.  Thanks a lot. 

RESHMA R

[Nimish Desai]

Hello friends.

I am trying to implement vrptw using or tools. I am pretty new to this. I am using the distance matrix calculated by google and then providing the time window for my locations with demands. the solution returned is always 0. can someone help e out please ?

[Laurent Perron]

Check that (1) the distance matrix is integral, and (2) that the scale of the numbers is compatible with the time windows. 

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[Vincent Furnon]

And to double-check, did you add arc costs to your model ?

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[Nimish Desai]

Hello Laurent

Thank you so much for the response. I think what i am struggling with is the data for time matrix and time window. The time mateix returned by google direction matrix api is in seconds. As per the online reference example the time window is defined in units of time.

So if my demot operates from 9 am to 6 pm and if my location with demand operates between 2 pm to 3 pm , what should my time window array look like ?

Any help here will be highly appreciated and helpful.

Regards

Nimish Desai

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[Nimish Desai]

Yes I have added the ARC cost. I am 99% sure that my values on time matrix and time window are not the correct units or the time window data i have doesnt make sense. Does the time window need to be calculated with reference to the depot or something?

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[Laurent Perron]

Whatever, just be consistent

 

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[Nimish Desai]

Hello Laurent

I am still stuck at this point. Can you please please help me on how my timewindow array in seconds unit should look like for below 4 locations as sample ?

Depot working from 9 am to 6 pm

Location 1 working from 14:30 to 17:00

Location 2 working from 10:00 to 14:00

Location 3 working all day 00:00 to 23:59

Thank you for the help in advance 

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[Nimish Desai]

Hello friends 

Can you please help me with this question. I guess this is the last point I am stuck at for my final solution.

Regards

Nimish

[Laurent Perron]

(your)

Laurent Perron | Operations Research | lpe...@google.com | (33) 1 42 68 53 00

Le mar. 28 févr. 2023 à 11:33, Laurent Perron <lpe...@google.com> a écrit :

count the second from midnight to you time

Laurent Perron | Operations Research | lpe...@google.com | (33) 1 42 68 53 00

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[Laurent Perron]

count the second from midnight to your time

Laurent Perron | Operations Research | lpe...@google.com | (33) 1 42 68 53 00

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[Laurent Perron]

Sorry for the spam. 

Le mer. 2 août 2023, 11:59, Waqarmir waqarmir <waqarmirw...@gmail.com> a écrit :

According to my personal experience, organic seeds are better then heirloom seeds. I am also a passionate gardener and I often practice growing vegetables in my garden. I am sharing my experiences on my web page.

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