Space-filling curves for 2-simplicial meshes created with bisections and reflections

summary:Numerical experiments in J. Maubach: Local bisection refinement and optimal order algebraic multilevel preconditioners, PRISM-97 conference Proceedings, 1977, 121–136 indicated that the refinement with the use of local bisections presented in J. Maubach: Local bisection refinement for $n$-simplicial grids generated by reflections, SIAM J. Sci. Comput. 16 (1995), 210–227 leads to highly locally refined computational 2-meshes which can be very efficiently load-balanced with the use of a space-filling curve. This paper introduces the construction of this curve which can be produced at almost no costs, proofs that all its properties are invariant under local bisection, and comments on the 3-dimensional case. With the use of a space-filling curve (which passes through all triangular elements), load balancing over several processors is trivial: The load can be distributed over $N$ processors by cutting the curve into $N$ almost equilength parts. Each processor then operates on the triangles which are passed by its part of the curve