Implementation of sub-structuring within an object-oriented framework

This paper describes how the U'DU decomposition method and sub-structuring algorithms can be implemented using object-oriented techniques. It is shown that this enables the algorithms to be implemented very concisely. Moreove r, there is no increase in code complexity when the algorithms are extended to take account of sparsity. The sub-structuring, or domain decomposition algorithms are expressed in block matrix terms, and classes are used to rep resent each of these matrices. The solution processes are incorporated in a finite element program. The finite element program uses a distributed data structure, and this facilitates a straightforward interface between the fi nite element program and the mathematics. Moreover, the program possesses a clear control structure for responding to user changes to the finite eleme nt model. (C) 2001 Civil-Comp Ltd and Elsevier Science Ltd. All rights rese rved.