Encyclopedia of Operations Research and Management Science

2013 Edition
| Editors: Saul I. Gass, Michael C. Fu

Pivot-Selection Rules

Reference work entry
DOI: https://doi.org/10.1007/978-1-4419-1153-7_200601

In the simplex method, the pivot selection rules determine which variable is to enter the basic solution and which variable is to be dropped. Depending on the solution at hand, the rules are designed to preserve feasibility (nonnegativity) of the solution (primal-simplex method), or to preserve the optimality conditions (dual-simplex method). In either case, the rules attempt to select an entering variable that would cause and improvement in the objective function. These rules are often augmented with anti-degeneracy or anticycling rules, and procedures for maintaining sparsity and numerical accuracy.


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© Springer Science+Business Media New York 2013