P-median

Localization problems have been the object of study for centuries, but it was not until the focus of the Operational Research when these problems became more interesting, being currently objects of study in many of the disciplines with a focus on these types of problems.

In a location problem, we have a set of demand points and a set of possible locations, we want to find the location of several services so that, when assigning the demand points to the services, it is optimized with some distance function , cost or time of the trip. This function is often referred to as an objective function, and among the most studied are the Center and Median functions.

The location models are applied to specific cases, their structure contains objectives, restrictions and variables that depend on each case of study. There is no generic model that is appropriate for all problems. Therefore, a model with a different objective can cause different solutions for the same case study.

The discrete models of location in networks can be classified according to distance. These models can be divided into models that are based on maximum distance and models based on total or average distance.