 technique for linear programs, called the simplex method, is a combination of the continuous and the discrete, a series of steps from one combination of constraints to another along a sequence of linear moves. 6 As the optimization involves more complex functions 6Our operations research friends will forgive us, we hope, for trying to sum up a vast area of re- search in a single sentence. Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Capacity and Quality Tradeoffs Capacity and Quality Principles and constraints, the solution technologies get more complicated and use more com- puter time. In any case of a constrained optimization, the optimal solution will divide the con- straints into slack and critical resources. The slack resources have a value of zero so far as the optimal value is concerned. However, the critical resources have some posi- tive value, some positive effect on the optimal solution, if we can increase them a little bit. The understanding of the incremental value of relaxing constraints is an important part of the solution of a constrained optimization. These incremental values, sometimes called prices, describe the impact and importance of the constraints in a constrained op- timization problem. If all the constraint variables are slack, then the constraints are relevant, and the optimization is really an unconstrained optimization. 22.6 Optimization Variables Deciding on the relative values of the various components of a business solution is a difficult and often political process. We study a problem, we look at as many aspects of it as we can, and we try to model as much of this as we can in a mathematical formu- lation. The list of objective function parameters can be long, and their relationships can be confusing. Getting consensus on the relative importance of various aspects of an op- timization problem can be a dif