Introduction to Linear
Programming
The development of linear programming has been ranked among the most important scientific advances of the mid-20th century, and we must agree with this assessment. Its impact since just 1950 has been extraordinary. Today it is a standard tool that has saved many thousands or millions of dollars for most companies or businesses of even moderate size in the various industrialized countries of the world; and its use in other sectors of society has been spreading rapidly. A major proportion of all scientific computation on computers is devoted to the use of linear programming. Dozens of textbooks have been written about linear programming, and published articles describing important applications now number in the hundreds.
What is the nature of this remarkable tool, and what kinds of problems does it address? You will gain insight into this topic as you work through subsequent examples. However, a verbal summary may help provide perspective. Briefly, the most common type of application involves the general problem of allocating limited resources among competing activities in a best possible (i.e., optimal) way. More precisely, this problem involves selecting the level of certain activities that compete for scarce resources that are necessary to perform those activities. The choice of activity levels then dictates how much of each resource will be consumed by each activity. The variety of situations to which this description applies is diverse, indeed, ranging from the allocation of production facilities to products to the allocation of national resources to domestic needs, from portfolio selection to the selection of shipping patterns, from agricultural planning to the design of radiation therapy, and so on. However, the one common ingredient in each of these situations is the necessity for allocating resources to activities by choosing the levels of those activities.
Linear programming uses a mathematical model to
References: 9th ed., West, St. Paul, MN, 2000, chaps. 2, 4. 2. Gass, S.: An Illustrated Guide to Linear Programming, Dover Publications, New York, 1990. 3. Hillier, F. S., M. S. Hillier, and G. J. Lieberman: Introduction to Management Science: A Modeling and Case Studies Approach with Spreadsheets, Irwin/McGraw-Hill, Burr Ridge, IL, 2000, chaps 4. LINGO User’s Guide, LINDO Systems, Inc., Chicago, IL, e-mail: info@lindo.com, 1999. 5. MPL Modeling System (Release 4.0) manual, Maximal Software, Inc., Arlington, VA, e-mail: info@maximal-usa.com, 1998. 6. Williams, H. P.: Model Building in Mathematical Programming, 3d ed., Wiley, New York, 1990.