Originally posted by: SystemAdmin

[shadi said:]

hi,
im using column generation method, and i want to have the ability to generate and columns(dutirs) that have the following structure:

Trip1     Location1  -> Location2
            Trip2     Location2  -> Location1
            Trip3     Location2  -> Location1
            Trip4     Location1  -> Location2
            Trip5     Location2  -> Location1

i mean to include and duties that has empty trips, in the above example in order to make trips 3 bus must go from
Location1 to Location2 empty. but this can happen when:

ArrTime[trip2] + emptyBusTime<DepTime&#91;trip3&#93; <br />where: emptyBusTime is the duration in min when an empty bus travel from location1 to location2.

thanks in advanced
Kshieboun Shadi


#DecisionOptimization
#OPLusingCPOptimizer

Originally posted by: SystemAdmin

[shadi said:]

hi,
in other words, what is the constraint that enforce the ith trip to start from the end location of the (i-1)th trip in the cp model?????

thanks



#DecisionOptimization
#OPLusingCPOptimizer

Originally posted by: SystemAdmin

[Didier Vidal said:]

This depends on your model, and how you decided to encode the decision variables. Without a small code sample that defines the relevant variables, it's hard to answer.

For instance, you could define a startLocation and endLocation for each trip, and simply write


  forall(trip in 0..nbTrip - 1)
    endLocation[trip] == startLocation[trip + 1];


But that example is assuming a lot (for instance that the number of trips in a duty is not a decision variable).


Didier.
#DecisionOptimization
#OPLusingCPOptimizer