Structuring problems for analysis with electronic spreadsheets

Abstract

This paper discusses a method which uses directed graphs to reveal the underlying structure spreadsheet problems. Advantage is taken of the fact that there is a great deal of similarity among the two main classes of spreadsheet problems: those which are acyclic, and those involving cycles. For acyclic problems, a logical numbering can be assigned to cells, and the cell relationships may be shown in the form of a Cell Relationship Diagram (CRD . For cyclic problems, a pseudo CRD is used in order to break the cycles and derive pseudo-logical numberings for the cells. Cyclic spreadsheets are shown to contain fixed point problems, and three iterative numerical solution techniques (successive substitution, Newton-Raphson, and Gauss-Seidel) are described in terms of implementation and convergence properties, and demonstrated with several examples.