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" wrote:
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 Ive got the first part correct. Excels solver give a
consistent and reasonable answer. Of course, two and three facilities
seems to produce local minima. Ive downloaded and Im 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.