Every Problem in this Campaign is one instance of the MIPLIB 2017 Collection. The Problem binds two reference inputs:
target (JSON): the pinned MIPLIB snapshot for the instance - its name, status_class
(easy/hard/open), solu_status (opt/best/unkn/inf/unbd), the recorded objective
(null if none), objective_sense, whether the MPS is bound (instance_bound), and
the official instance sha256 and download URL.instance (gzip MPS): the official instance file, byte-identical to MIPLIB's
collection.zip. Absent when the file is too large for the sandbox; then download it
from the URL in target and verify the sha256.One artifact in role solution: a MIPLIB .sol file (plain text or gzip), see
solution-format.md. It MUST contain an =obj= <value> line with
the objective value you computed; the official checker refuses files without it.
The sandbox runs the official MIPLIB 2017 solchecker (from
miplib2017-testscript-v1.0.4.zip, exact rational arithmetic) with the official
tolerances: 1e-4 absolute on linear constraints and bounds, 1e-4 on integrality, and the
checker's own objective tolerance on your =obj= line. Then:
| target.solu_status | Contract | verified means |
|---|---|---|
| opt / best / unkn | score | feasible; score = objective in minimization form (negated for OBJSENSE MAX). Evidence says whether you matched or improved the MIPLIB value. Beating a proven optimum is inconclusive (needs a human). |
| inf / unbd | pass_fail | feasible point. For =inf= this refutes MIPLIB's recorded status. Proofs of infeasibility/unboundedness are NOT checkable here. |
inconclusive is never a finding against you: it means no =obj= line, an =infeas=
claim, an unreadable file, an unbound instance, or a checker timeout.
target.objective first. For =opt= instances the record is closed: a feasible
solution reaching the optimum is a full-score result; for =best= instances any
strictly better feasible solution is a genuine contribution - also report it to
MIPLIB (miplibsolutions@zib.de) with your solution file.instance bytes served by TfP rather than re-downloading,
so the file you solved is exactly the file that is checked.