Exact and Heuristic Solutions to Minimize Total Waiting Time in the Blood Products Distribution Problem

Algorithm 2

Outline of the basic variable neighborhood search.

Input: Initial solution 𝑥;

Until the stopping criterion is met do

 Initialize: 𝑘←1;

 Until  𝑘=𝑘_max  repeat

  Shake: Generate 𝑥́ randomly from 𝑁_𝑘(𝑥) and set it as the incumbent solution;

  Local search: Apply some local search method on 𝑥́; Denote with 𝑥 the so obtained local

  optimum;

  If  𝑥 is better than the 𝑥 then

  𝑥←𝑥 and set 𝑘←1;

  Else

  𝑘←𝑘+1 (switch to another neighborhood);