Binary integer non-linear programming excel solver premium

[Gary]

Howdy,

I am working a homework problem involving non-linear programming for
an operations research class. The problem is in three parts. The
objective is to minimize the total distance traveled between a
facility and thirty different towns each year by optimally locating
the facility amongst the towns. There are a fixed number of trips
between each facility and each town each year. The second and third
parts of the problem require locating two and three facilities. I
believe I’ve got the first part correct. Excel’s solver give a
consistent and reasonable answer. Of course, two and three facilities
seems to produce local minima. I’ve downloaded and I’m trying to use
Frontline systems Premium solver add-in. Other than randomly sorting
through different starting points, how do I configure the premium
solver to identify the global maximum for each case? Thanks for any
advice or help.

-g

 

[Bob Bridges]

Is this just the traveling-salesman problem in another guise, Gary? Last I
heard, no one has come up with a theoretical solution, beyond the brute-force
method of trying all possible combinations, which in a population of 30 towns
is impractical. If you could locate your facility in a geometrically random
location -- without regard to the road layout, I mean -- it might be
different. But I speak in ignorance of this area of mathematics.

 

[Gary]

Its not quite a traveling salesman problem. Each town makes x number
of trips to a single facility. The facilities are to be located so as
to minimize the total distance traveled from all towns to each towns
respective facility. So, the distance between each town and its
facility is weighted. The real problem is avoiding solver settling on
a locally optimal solution. I need to find a way to get solver to
brute force it in a way and find the globally optimal solution.