Building graph separators with the recursive rotation algorithm for the nested dissection method

A recursive rotation algorithm is built and investigated. The algorithm is a possible version of the nested dissection algorithm. The Liu algorithm builds a matrix graph separator by means of rotation of an elimination tree, which reduces the height of the latter. In this case, the nodes of the matrix graph are previously reordered by one of the well-known Cuthill-McKee algorithms, the reverse Cuthill-McKee algorithm, and the King algorithm. Then this procedure is recursively repeated. The recursive rotation algorithm is compared with the multilevel and spectral methods of graph separation for 2D finite-element grids.