Menu
▾
▴
Re: [Choco-users] solveAll() bug?
|
From: Guillaume R. <Gui...@em...> - 2006-11-17 23:29:33
|
Hi,
This strange behavior is due to the fact that you use SolveAll() before=20
Solve(). SolveAll() and Solve()+nextSolution()'s loop are equivalents=20
(in other words you search for all the solutions twice), so usually we=20
don't do that :) What do you want to do ?
-Guillaume
Varun Jain a =E9crit :
> Hi,
>
> Thank you very much for your quick reply. I guess the real question I=20
> wanted to ask was that if choco could return results even when the=20
> problem is infeasible. I did my experiment with the following problem:
>
> ------------------------------------------------
> Variables:
> Variable0, Domain: {3, 1, 4}
> Variable1, Domain: {2, 4, 6}
> Variable2, Domain: {2, 1}
> Variable3, Domain: {3, 1}
> Variable4, Domain: {6, 2, 5}
>
> Constraints:
> Constraint0, on variables 2 , Allowed values:
> 2
> Constraint1, on variables 2, 4 , Allowed values:
> 1, 6
> 2, 2
> Constraint2, on variables 4, 2 , Allowed values:
> 5, 2
> Constraint3, on variables 1, 3 , Allowed values:
> 2, 3
> ------------------------------------------------------
>
> All the constraints were created using Problem.makeTupleFC(IntVar[]=20
> varList, ArrayList tuples, boolean feasible). For example, the first=20
> constraint can be created as follows:
>
> ------------------------------------------
> Problem chocoCSP;
> /**
> * Set up the variables using chocoCSP.makeEnumIntVar()
> */
> IntVar[] varList =3D new IntVar[1];
> varList[0] =3D variables[2];
> ArrayList<int[]> tuples =3D new ArrayList<int[]>();
> tuples.add(new int[]{2});
> chocoCSP.makeTupleFC(varList, tuples, true);
> -------------------------------------------------
>
> To obtain solutions, I did the following:
>
> -----------------------------------------------
> System.out.println("SolveAll says: " + chocoCSP.solveAll());
> System.out.println("isFeasible says: " + chocoCSP.isFeasible());
> System.out.println("Choco Solutions");
> if(chocoCSP.solve() =3D=3D Boolean.TRUE) {
> do {
> for(int i =3D 0; i < chocoCSP.getNbIntVars(); i ++) {
> System.out.print(((IntDomainVar)=20
> chocoCSP.getIntVar(i)).getVal() + ", ");
> }
> System.out.println();
> } while(chocoCSP.nextSolution() =3D=3D Boolean.TRUE);
> }
> -----------------------------------------------
>
> Here is the output:
>
> SolveAll says: true
> isFeasible says: false
> Choco Solutions
> 1,2,2,3,5,
> 3,2,2,3,5,
> 4,2,2,3,5,
>
>
> Clearly, the solutions do not satisfy all the constraints. For=20
> instance, none of the solutions satisfy Constraint1. Is this expected=20
> behaviour??
>
> Thanks again,
> -Varun.
>
>
>
>
> -----------------------------------------------------------------------=
-
> > Date: Fri, 17 Nov 2006 11:31:40 +0100
> > From: Gui...@em...
> > To: jai...@ho...
> > Subject: Re: [Choco-users] solveAll() bug?
> >
> > Hi,
> >
> > I am not sure to understand what you try to do but i have some=20
> answers :)
> > -SolveAll still return true (it is hardcoded) but you can modify the
> > function solveAll() in choco.Problem
> >
> > In choco.Problem:
> > public Boolean solveAll() {
> > solver.firstSolution =3D false;
> > solver.generateSearchSolver(this);
> > solver.launch();
> > return Boolean.TRUE;
> > }
> >
> > -What kind of error do you have ? How do you implement the
> > nextSolution() loop ?
> > BTW, if you use nextSolution() to display solutions, you can use=20
> instead:
> >
> > "Solver.setVerbosity(Solver.SOLUTION);" before to begin to solve
> > and "Solver.flushLogs();" to print solutions
> >
> > else:
> >
> > if (pb.solve() =3D=3D Boolean.TRUE) {
> >
> > do {
> > //Code
> > }
> > } while(pb.nextSolution() =3D=3D Boolean.TRUE);
> > }
> >
> >
> > I hope it helps you... :)
> > -Guillaume
> >
> > Varun Jain a =E9crit :
> > > Hi..
> > > Is there any reason why the solveAll() method will return true=20
> even if
> > > there is no solution that satisfies all constraints. I was getting
> > > this behaviour so I did a little experiment: I set up a simple=20
> problem
> > > and executed the following:
> > >
> > > Problem chocoCSP;
> > > //...............
> > > //-----Set up the problem
> > > //...............
> > > System.out.println("SolveAll says: " + chocoCSP.solveAll());
> > > System.out.println("isFeasible says: " + chocoCSP.isFeasible());
> > >
> > > The following was the output
> > >
> > > SolveAll says: true
> > > isFeasible says: false
> > >
> > > I thought solveAll() returns false if no solution exists. Also, for
> > > this problem, the solutions I get from the nextSolution() method do
> > > not satisfy all constraints. Any explainations would be really=20
> helpful?
> > >
> > > Thanks,
> > > -Varun.
> >
> -----------------------------------------------------------------------=
-
> Be one of the first to try Windows Live Mail.=20
> <http://ideas.live.com/programpage.aspx?versionId=3D5d21c51a-b161-4314-=
9b0e-4911fb2b2e6d>=20
>
> -----------------------------------------------------------------------=
-
>
> -----------------------------------------------------------------------=
--
> Take Surveys. Earn Cash. Influence the Future of IT
> Join SourceForge.net's Techsay panel and you'll get the chance to share=
your
> opinions on IT & business topics through brief surveys - and earn cash
> http://www.techsay.com/default.php?page=3Djoin.php&p=3Dsourceforge&CID=3D=
DEVDEV
> -----------------------------------------------------------------------=
-
>
> _______________________________________________
> Choco-users mailing list
> Cho...@li...
> https://lists.sourceforge.net/lists/listinfo/choco-users
> =20
|
