In this paper, we investigate the computational behavior of the exterior point simplex algorithm. Up until now, there has been a major difference observed between the theoretical worst case complexity and practical pe...
详细信息
In this paper, we investigate the computational behavior of the exterior point simplex algorithm. Up until now, there has been a major difference observed between the theoretical worst case complexity and practical performance of simplex-type algorithms. Computational tests have been carried out on randomly generated sparse linear problems and on a small set of benchmark problems. Specifically, 6780 linear problems were randomly generated, in order to formulate a respectable amount of experiments. Our study consists of the measurement of the number of iterations that the exterior point simplex algorithm needs for the solution of the above mentioned problems and benchmark dataset. Our purpose is to formulate representative regression models for these measurements, which would play a significant role for the evaluation of an algorithm's efficiency. For this examination, specific characteristics, such as the number of constraints and variables, the sparsity and bit length, and the condition of matrix A, of each linear problem, were taken into account. What drew our attention was that the formulated model for the randomly generated problems reveal a linear relation among these characteristics.
We resolve the problem of degeneracy in a recently developed primal-dual simplexalgorithm for general linear programming problems (Chen et al., 1994). We show that the algorithm cycles. It is also shown that if ties ...
详细信息
We resolve the problem of degeneracy in a recently developed primal-dual simplexalgorithm for general linear programming problems (Chen et al., 1994). We show that the algorithm cycles. It is also shown that if ties are broken by an arbitrary cycling-free pivot rule of the classical primal simplexalgorithm, then the refined primal-dual algorithm does not cycle. Exponential worst-case behaviour is shown and relations with other algorithms are discussed.
暂无评论