The instance files in this directory were first generated with the Wildlife corridor design instance file generator, and then extended with a budget constant using the budget calculator in this repository.
The files are named as follows:
{$X}P_{$Y}R_{$Z}b_{corr|uncorr}.cor
where {$X} is the total number of parcels (nodes) in the graph, {$Y} is the number of
reserves (distinguished nodes) that we want to connect. Note that this means that {$X} - {$Y}
parcels (nodes) are not reserves. {$Z} represents the budget percentage, i.e. how much more
than the budget's lower bound the budget is. For example, if the budget percentage is 10,
then the budget constant will be 10% higher than the lower bound for the budget.
The utlities and costs of each parcel are generated in two different ways with the instances
generator that are represented by either corr or uncorr. With the corr option, the
utility/costs between adjacent parcels/nodes are weakly correlated, and with uncorr the
utility/cost values are randomly assigned to the parcels. This means that the corr
variant is slightly more realistic than the uncorr variant.
16P_2R_05b_corr.cor
has 16 parcels (nodes) of which 2 are reserves, with a budget percentage of 5%, generated with weakly correlated cost/utility values.
Please note that I slightly adapted the instance generator to assure that all generated utility values are non-negative. The exact command to generate the instance is given in the comment section of each instance.