UflLib

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This page contains a collection of benchmark instances for the Uncapacitated Facility Location Problem (UFLP), which is also known as the Simple Plant Location Problem (SPLP) or the (Uncapacitated) Warehouse Location Problem. This problem from Operational Research has been studied intensively during the last years, and here a collection of standard benchmark problems can be accessed. Furthermode there are code and binaries of benchmark generators for different operating systems and code for several solution algorithms available.
If you find any errors or like to comment on this page, or if you have additional benchmarks or code material, please write an e-mail to Martin Hoefer.

News

13.07.2007	Optimal solutions were added for 16 of 18 instances in the K-median package, only 2500-10 and 3000-100 remain unsolved. For the symmetric and asymmetric Koerkel-Ghosh packages the instances gs250a-1 and ga250a-1 have been solved. Thanks to Cesar Beltran-Royo, Jean-Philippe Vial, and Antonio Alonso-Ayuso for providing the solution files. This paper discusses a solution technique and some additional results.
07.02.2005	The evaluation is completed. Improved solutions exist for 5FPP_11S.txt - opt: 36226 - prev. reported: 36228 23FPP_17S.txt - opt: 54557 - prev. reported: 54558 1331GapBS.txt - opt: 42169 - prev. reported: 42171 For all instances not solved to optimality .bub-files were included that contain an upper bound on the optimum solution.
06.08.2004	Some of the .opt-solutions could slightly be improved. Thanks to Pascal van Hentenryck for bringing this to my attention. I started to re-evaluate all the solutions provided on this page.
21.10.2003	New: Chessboard, Eukldian, Perfect Code, Uniform and Koerkel-Ghosh benchmarks
13.06.2003	Finally all optimal solutions of the Large duality gap and Finite projective planes benchmarks are included in the packages.
15.01.2003	New: Large duality gap and finite projective planes benchmarks More information and generators can be found on Yuri Kochetov's web page.

For everyone, who does not know what we are talking about, here's a tiny

Problem description

The uncapacitated facility location problem can be stated as follows:
There are a number of m cities/customers and n potential facility locations. With each location we associate a nonnegative opening cost f_i. Between each facility i and each city j there is a nonnegative connection or service cost c_ij. The task is to connect each city to exactly one opened facility the way that the sum of all costs is minimized.