constraint-satisfaction

Possible NP-complete problem?

I'd just like someone to verify whether the following problem is NP-complete or if there is actually a better/easier solution to it than simple brute-force combination checking. We have a sort-of resource allocation problem in our software, and I'll explain it with an example. Let's say we need 4 people to be at work during the day-shi...

Java Constraints Library (JCL) problem: how to represent addition?

I have to solve a CSP logic problem using Java Constraints Library. For now I've managed to represent some constraints of the problem, most of them are based on "equals" and "not equals" binary constraints. My doubt is, how to represent an addition based constraint? Example: variable1 belongs to DomainA variable2 belongs to DomainB var...

zChaff not showing output

Hello, So I downloaded the latest version of zChaff (2007), and was trying out some very simple SAT problems. But zChaff does not output the solution (variable assignments). A very simple example input: p cnf 2 2 1 2 0 1 -2 0 And what I get: c 2 Clauses are true, Verify Solution successful. Instance Satisfiable 1 -2 Random Seed Used...

Constraint Satisfaction Problem: Choosing real numbers with certain characteristics

I have a set of n real numbers. I also have a set of functions, f_1, f_2, ..., f_m. Each of these functions takes a list of numbers as its argument. I also have a set of m ranges, [l_1, u_1], [l_2, u_2], ..., [l_m, u_m]. I want to repeatedly choose a subset {r_1, r_2, ..., r_k} of k elements such that l_i <= f_i({r_1, r_2, ...,...