If I'm understanding your message correctly, you mean that the method
AC-3 "does nothing" for the CSP instance you are working on? Certainly
it has a purpose -- to enforce arc consistency. If the CSP passed into
the method is arc-consistent in the first place, then the method won't
make any changes.
The general idea behind arc-consistency is to preemptively remove
values from the domains that are inconsistent with the constraints of
the problem. It is always a good idea to evaluate how useful AC is for
your particular CSP -- for some problems, it is too expensive to use
it. (Source: http://citeseer.nj.nec.com/55167.html
, p. 11)
You can look at this web page for supplemental material on AC-3.
--- In firstname.lastname@example.org, "Alex0215" <h5641kimo@y...> wrote:
> hi all :
> i just download the java code from the respository,
> and then i try out the CSP search program,
> but i find out that the things weird,
> the ac-3 algorithm, that is. in the code ,
> a method name as AC3(csp) , and i observe
> the detail code and figure out that it does nothing !!!
> why the method AC-3 seems so weird??
> somebody can give me the clues ??