CVRPLIB offers a selection of
CVRP problem instances. This function downloads the instance data and
conveniently makes it available to be fed into solver functions, e.g. with
clarke_wright_cvrplib(). The primary purpose for those instances is
benchmarking / comparing speed as well as performance of solvers.
Arguments
- qualifier
The qualifier of the problem instance. E.g. "tai150d". This can either be inferred directly from the website or by the output of
cvrplib_ls(). Can be a vector to download several instances at once, which is preferable to repeated calls since the list of available instances is only requested once.- cvrplib_url
The base URL of the CVRPLIB website. Defaults to https://galgos.inf.puc-rio.br.
Value
For a single qualifier, returns a "cvrplib_instance" object. For several
qualifiers, returns a list() of those objects, named by qualifier. Note that
a vector of length one counts as a single qualifier.
A "cvrplib_instance" object contains CVRPLIB problem
instance data. Its best_known_cost is the cost of the best known solution
provided by CVRPLIB (not necessarily a proven optimum), or NA if CVRPLIB
provides no solution file for the instance. A solution file that exists but
can not be downloaded raises an error.
Instances defined by an explicit distance matrix store it as distances, a
dist object, and have NA coordinates in pos. Instances defined by
coordinates have distances set to NULL.
See also
Other cvrplib:
clarke_wright_cvrplib(),
cvrplib_ls()