gmut-75-50

primal-infeasible

The instance

as published

Variables: 68,865
Constraints: 2,565
Nonzeros: 571,475
Format: MPS, gzipped

Where it comes from

provenance

A branch-and-bound run reached this node's parent and split on a variable. This instance is the side the search did not explore, and it has no feasible point.

branch taken by the search
x224_3 ≤ 0
this instance, the other side
x224_3 ≥ 1 at depth 2,523

Depth in the tree: 2,523
Bounds tightened vs. source: 2,523
Branch variable: x224_3

Tightened bounds

2,523 entries

x1_1<=0x1_2<=0x1_3>=1x2_3<=0x2_4<=0x2_5<=0x3_1<=0x3_2<=0x3_3<=0x4_0>=1x5_1<=0x5_2<=0

12 of 2,523 shown. The complete list is in the sidecar.

Also published in the dual-infeasible set view →

Download

gmut-75-50_if.mps.gz3.04 MiB gmut-75-50_if.meta.json44 KiB

The sidecar carries the full provenance, including the fields this page truncates.

Source instance

Namegmut-75-50

Submitted byNora Konnyu

Groupgmu

TermsNo licence of record

Imported from the MIPLIB2010 submissions. It predates MIPLIB's submission form, and the licence that form required. See LICENSE.

set_packingvariable_bound

Timber harvest scheduling model. Solved by ParaXpress in a 12288 core supercomputer run on HLRN III. These are harvest scheduling models of hypothetical forest planning problems where net timber revenues are maximized over a planning horizon subject to four sets of constraints: 1. Each management unit can be harvested only once over the planning horizon, 2. Volume harvested in one planning period should not be less or more than some portion of that in the preceding period, 3. Area-weighted average age of the forest by the end of the plan should notbe less than a certain target age. 4. Clearcut size in any planning period has to be below a specific limit. Decision variable are management units and generalized management units (group of management units with a combined area not exceeding the limit on clearcut size) and can be either fully harvested or left untouched in any planning period, therefore there is a binary restriction on the decision variables.

Source description quoted from MIPLIB 2017; links and mathematical notation formatted for the web.

View on MIPLIB 2017 →