European Journal of Operational Research 69 (1993) 277-278 277 North-Holland

OR Software-ORSEP Operations Research Software Exchange Program Edited by Professor H.W. Hamacher

WHAP: Warehouse Allocation Program

Richard L. Francis, Cecilia M.C. Lindemalm and Kristina I. Olssen

Keywords: Warehousing; Layout; Transportat ion Hardware Information: IBM PC or compatible running MS-DOS. Software Information: W H A P is provided on a 3.5" floppy disk. the code is written in Turbo Pascal, v. 5.5. Contact Address: Prof. R.L. Francis, Depar tment of Industrial and Systems Engineering, 303 Weil Hall, University of Florida, Gainesville, FL 32611, USA.

The code W H A P (Warehouse Allocation Pro- gram) implements a warehouse layout model pre- sented in Chapter 5 of Facility Layout and Loca- tion: an Analytical Approach, by Francis, McGin- nis and White, Prentice Hall, 1992. The code is intended for educational purposes only. By solv- ing a transportat ion problem, the code finds a warehouse layout that minimizes total direct rec- tilinear travel distance between the docks and the

Public domain software in OR can be contributed to ORSEP by sending a diskette containing the code and the code description to Professor H.W. Hamacher, Department of Math- ematics, University of Kaiserslautern, D 6750 Kaiserslautern, Germany, E-mail: hamacher@dkluniltl.bitnet Copies of published codes can be requested from the same address or directly from the authors by sending a formatted diskette and a self-addressed envelope. See EJOR 48(1) (1990) 161-162, for details.

product storage locations (called bays or slots), assuming products are stored and transported in unit loads and there is a F IFO inventory policy.

The warehouse is idealized as a matrix of bays. There can be as many as 37 columns, and 21 rows. There can be as many as 25 products, and 15 docks. For each product, its fractional usage of each of the docks, the number of bays required, and the throughput, must be given. Also dock locations must be given, as well as the x and y bay dimensions, number of columns, and number of rows. The code has the ability to allow bays to be excluded from use (thus allowing for aisles, non rectangular shapes, products with fixed locations, etc.) and can also accept a user-specified layout, which it will compare with the one it computes.

A problem can either be created by modifying the data for a default problem, or the data can be read in from a previously created input file. Solved problems can also be saved for later runs.

The code is written in a user-friendly fashion, with menus, and the warehouse layout is dis- played in graphics with colors.

Problems with more than 25 docks can be solved by aggregating products. Sufficient condi- tions for the aggregation to cause no loss of accuracy are known. Any p products, p >__ 2, all having the SAME R A T I O S of throughputs to slot requirement, and the SAME fractional dock usages, can be aggregated with no loss of accu-

0377-2217/93/$06.00 © 1993 - Elsevier Science Publishers B.V. All rights reserved

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racy into a single product whose throughput is the total of the p throughputs, whose slot require- ment is the total of p slot requirements, and whose fractional dock usages are the same as for

any one of the products. Once the layout is found, the layout for these p products can be obtained by dividing up the layout for the single "aggregate" product in any convenient way.