A Proposal for the Cooperation of Solvers in Constraint Functional Logic Programming

Abstract

This paper presents a proposal for the cooperation of solvers in constraint functional logic programming, a quite expressive programming paradigm which combines functional, logic and constraint programming using constraint lazy narrowing as goal solving mechanism. Cooperation of solvers for different constraint domains can improve the efficiency of implementations since solvers can take advantage of other solvers' deductions. We restrict our attention to the cooperation of three solvers, dealing with syntactic equality and disequality constraints, real arithmetic constraints, and finite domain (FD) constraints, respectively. As cooperation mechanism, we consider to propagate to the real solver the constraints which have been submitted to the FD solver (and viceversa), imposing special communication constraints to ensure that both solvers will allow the same integer values for all the variables involved in the cooperation.