UflLib
GalvãoRaggi Benchmarks
The GalvãoRaggi benchmarks have a unique structure. There is always m = n. The underlying bipartite graph of the problem is randomly filled with edges to some respect. This arc density d is given upfront. Then the present arcs are assigned a cost sampled from a uniform distribution in the range [1, n] (except for n=150 we chose the range [1, 500]). The connection cost between a facility and a customer is the shortest path in this graph. The opening costs are sampled from a normal distribution. Parameters for the different problem classes are provided in the following table.
Problem size  Density  Fixed costs' parameters  

(m = n) 

mean  standard deviation 
10  0.300  4.3  2.3 
20  0.150  9.4  4.8 
30  0.100  13.9  7.4 
50  0.061  25.1  14.1 
70  0.043  42.3  20.7 
100  0.025  51.7  28.9 
150  0.018  186.1  101.5 
200  0.015  149.5  94.4 
From these 8 classes we only generated 10 instances for each of the classes with m = n = 50, 70, 100, 150 and 200. We believe the other classes to be too small for today's computers. Nevertheless, one can still download the code for a generator to produce some instances of these classes.
References
[1] 
R.D. Galvão and L.A. Raggi. A method for solving to optimality uncapacitated location problems. Annals of Operations Research 18:225244, 1989. 