Thursday, December 1, 2011

Modeling is more difficult than many people think…

From a Bachelors thesis:

Transportation

In this simple transportation model I see at least two problems.

The capacity constraint should probably look like:

forall (o in DCs)
  ctCapacity:
     sum(p in Products, d in Stores)
         Trans[p][o][d] <= Capacity[o];

The care needed to write correct models is often underestimated.

3 comments:

  1. Just because I want to understand more. The top one is simply because they doubled the transportation cost, when they were trying to do transportation between 2 locations instead?

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  2. Would this be not more obvious:

    Trans_Cost[p][o][p]+DC_Cost[p][o][d]

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  3. ahhhhh. yeah, that makes sense.

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