DM811 - Heuristics for Combinatorial Optimization
Sheet 6, Autumn 2010 [pdf format]

Prepare for class discussion an answer to the following exercise. Due date: December 17, 2010.

Exercise

Definition 1  p-Median Problem

Input: A set U of locations for n users, a set F of locations for m facilities and a distance matrix D=[dij] ∈ Rn× m.

Task: Select a set JF of p locations where to install facilities such that the sum of the distances of each user to its closest installed facility is minimized, i.e.,

min

 
i ∈ U
 
 
min
j ∈ J
 dij   |  J ⊆ F   and   |J|=p


Design construction heuristics and local search algorithms.

Exercise 2

A possible application of local search to the GCP defines the following:

Show that any local optimum of this function corresponds to a feasible coloring. Does a global optimum correspond to a coloring that use the minimal possible number of colors?