Uniform Random Binary DisCSP Generator in NetLogo

These are uniform random binary DisCSP generator in NetLogo. A randomly generated DisCSP is an example of a homogeneous unstructured problem. These problems have a number of variables with a fixed domain. Variables belonging to constraints are chosen at random. The randomly generated (binary) CSPs are characterised by the 4-tuple (n, m,p1,p2), where: - n is the number of variables; - m is the uniform domain size; - p1 is the portion of the n * (n - 1) /2 possible constraints in the graph; - p2 is the portion of the m*m value pairs in each constraint that are disallowed by the constraint. That is, p1 may be thought of as the density of the constraint graph, and p2 as the tightness of constraints.

We used binary constraints with the constraint density controlling how many constraints were generated and the constraint tightness determining the proportion of value combinations forbidden by each constraint. For example, a constraint density of 0.2 would generate 20% of the possible constraints in the problem (i.e. (n* (n-1)/2) * 0.2 where n is the number of variables) and a constraint tightness of 0.4 would prevent 40% of the possible value combinations of variables involved in a constraint from satisfying the constraint. Such uniform random constraints networks of n variables, k values in each domain, a constraints density of p1 and tightness p2, are commonly used in experimental evaluations of DisCSP algorithms.