Exploiting Single-Cycle Symmetries in Continuous Constraint Problems

Symmetries in discrete constraint satisfaction problems have been explored and exploited in the last years, but symmetries in continuous constraint problems have not received the same attention. Here we focus on permutations of the variables consisting of one single cycle. We propose a procedure that takes advantage of these symmetries by interacting with a continuous constraint solver without interfering with it. A key concept in this procedure are the classes of symmetric boxes formed by bisecting a n-dimensional cube at the same point in all dimensions at the same time. We analyze these classes and quantify them as a function of the cube dimensionality. Moreover, we propose a simple algorithm to generate the representatives of all these classes for any number of variables at very high rates. A problem example from the chemical field and a kinematics solver are used to show the performance of the approach in practice. Institut de Robòtica i Informàtica Industrial (IRI) Consejo Superior de Investigaciones Cient́ıficas (CSIC) Universitat Politècnica de Catalunya (UPC) Llorens i Artigas 4-6, 08028, Barcelona Spain Tel (fax): +34 93 401 5750 (5751) http://www-iri.upc.es Corresponding author: Vicente Ruiz de Angulo tel: +34 93 401 5752 [email protected] http://www-iri.upc.es/people/ruiz