Sparse Systems in Fixed Point Form

1) A method is shown for reducing dimension of sparse systems of equations given in fixed point form. Economic models provide examples. 2) A given box to be searched for solutions can be reduced using interval intersections. 3) Interval Newton-like methods using either derivatives or slopes can be applied to the reduced system.     

Sex differences in preferences for job attributes revisited.

A sample representative of the adult noninstitutionalized population of the continental US was stratified by sex and occupation. Data were derived from the 1974 General Survey conducted by the National Opinion Research Center, as reported by J. A. Davis (1975). Ss rank ordered 5 job attributes in terms of their importance: high income, security, short hours, advancement, and feelings of accomplishment. No sex differences were found. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parallel Inversion of Sparse Matrices.

This paper presents a parallel algorithm for obtaining the inverse of a large, nonsingular symmetric matrix A of dimension nxn. The inversion method proposed is based on the triangular factors of A. The task of obtaining the "sparse inverse' of A is represented by a directed acyclic graph. The relation between the triangulation graph and the sparse inversion graph is given. The algorithm and the graph for the full inversion of A is also given. It is shown that for any sparse symmetric matrix, and assuming enough processors are available, the full inverse of the matrix can be calculated in the same amount of time as the sparse inverse. For ideally sparse matrices (such as tridiagonal matrices) the order of computation required in both cases is of order log2n. For full matrices the order of computation is n log2n. Claims are substantiated using test data from several power systems.