An Extension of the WAM for Hybrid Interval Solvers Fr´ ed´ eric Goualard and Fr´ ed´ eric Benhamou IRIN, Universit´ e de Nantes B.P. 92208, 44322 Nantes Cedex 3 — France Frederic.[Goualard,Benhamou]@irin.univ-nantes.fr Laurent Granvilliers LIFO, Universit´ e d’Orl´ eans B.P. 6759, 45067 Orl´ eans Cedex 2 — France Laurent.Granvilliers@lifo.univ-orleans.fr Appears in: Journal of Functional and Logic Pro- gramming. Special issue on “Parallelism and Implementation Technology for Constraint Logic Programming”. MIT Press 1999 Abstract This paper discusses the implementation of DecLIC, an extension of the clp(fd) language to handle interval constraints. The main solv- ing capabilities of DecLIC are based on the use of two different levels of local consistency, namely hull-consistency and box ϕ -consistency, a slight yet computationally relevant generalization of box-consistency. Experimental evidence of the qualities and drawbacks of constraint solving based on these two notions is provided and benchmark com- parisons, carried out with a prototype of DecLIC, show that combi- nation permits, on certain cases, relevant speed-ups in the resolution process. The compiler of clp(fd) translates CLP programs to C code via the Warren Abstract Machine (WAM). The extension of the WAM instruction set necessary to support the new features of DecLIC is de- scribed, along with the new internal structures. 1