Three different classes of facility location problems are considered. The problem classes are
- The uncapacitated facility location problem (UFLP).
- The capacitated facility location problem (CFLP) without single-source constraints.
- The single source capacitated facility location problem (SSCFLP).
The instances are based on previous instances from the literature extended to two objectives and
stored in the instances folder. Instances are named Gadegaard16_<problem class>_<origin>_<problem>_<cost structure>.raw.
The instances for CFLP are a subset of the test bed created for the paper Klose and Görtz (2007)
consisting of 45 instances ranging from 100 customers and 100 facility sites to 200 customers and
200 facility sites (first 45 problems in sub folder CFLP_UFLP).
The instances for UFLP we use a slightly larger subset of the instances created by Klose and Gôrtz
(2007) consisting of 60 instances ranging in size from 100 customers and 100 facilities to 100
customers and 500 facility sites (all 60 problems in sub folder CFLP_UFLP). .
The instances for SSCFLP are the instances proposed in Holmberg, Rônnqvist,
and Yuan (1999) that consists of 71 instances as well as 57 instances from the testbed used
in Díaz and Fernández (2002). All instances are in the sub folder SSCFLP.
For each testbed three cost structures for the
We use the following parameter names for the uncapacitated, capacitated, and single source capacitated facility location facility location problems:
-
$n$ = number of potential facility sites -
$m$ = number of customers -
$s_i$ = capacity of facility$i$ -
$f_i$ = fixed cost of opening facility$i$ -
$d_j$ = demand at customer$j$ -
$c_{i,j}$ = cost of supplying all customer$j$ 's demand from facility$i$ -
$t_{i,j}$ = travel time between facility$i$ and customer$j$
The instances have the following format:
n
m
s_1 f_1
s_2 f_2
...
s_n f_n
d_1 d_2 ... d_m
c_{1,1}... c_{1,m}
c_{2,1}... c_{2,m}
...
c_{n,1}... c_{n,m}
t_{1,1}... t_{1,m}
t_{2,1}... t_{2,m}
...
t_{n,1}... t_{n,m}
If the instance corresponds to an uncapacitated facility location problem (UFLP), then the demand and capacity parameters in the input file are ignored and demand is set to