Optimization Status Codes#
Once an optimize call has returned, the Gurobi optimizer sets the
Status attribute of the model to one of several possible
values. The attribute takes an integer value, but we recommend that you
use one of the predefined status constants to check the status in your
program. Each code has a name, and each language requires a prefix on
this name to obtain the appropriate constant. You would access status
code OPTIMAL in the following ways from the available Gurobi
interfaces:
Language |
Status Code |
|---|---|
C |
|
C++ |
|
Java |
|
.NET |
|
Python |
|
In MATLAB and R, status codes are returned as strings (e.g.
'OPTIMAL').
Possible status codes are as follows. Note that for statuses involving limits or other early termination of the optimization, if the feasibility of the reported solution is not evident from the status, you can assess the feasibility by accessing the appropriate solution quality attribute.
Status code |
Value |
Description |
|---|---|---|
|
1 |
Model is loaded, but no solution information is available. |
|
2 |
Model was solved to optimality (subject to tolerances), and an optimal solution is available. |
|
3 |
Model was proven to be infeasible. |
|
4 |
Model was proven to be either infeasible or unbounded. To obtain a more definitive conclusion, set the DualReductions parameter to 0 and reoptimize. |
|
5 |
Model was proven to be unbounded. Important note: an unbounded status indicates the presence of an unbounded ray that allows the objective to improve without limit. It says nothing about whether the model has a feasible solution. If you require information on feasibility, you should set the objective to zero and reoptimize. |
|
6 |
Optimal objective for model was proven to be worse than the value specified in the Cutoff parameter. No solution information is available. |
|
7 |
Optimization terminated because the total number of simplex iterations performed exceeded the value specified in the IterationLimit parameter, or because the total number of barrier iterations exceeded the value specified in the BarIterLimit parameter. |
|
8 |
Optimization terminated because the total number of branch-and-cut nodes explored exceeded the value specified in the NodeLimit parameter. |
|
9 |
Optimization terminated because the time expended exceeded the value specified in the TimeLimit parameter. |
|
10 |
Optimization terminated because the number of solutions found reached the value specified in the SolutionLimit parameter. |
|
11 |
Optimization was terminated by the user. |
|
12 |
Optimization was terminated due to unrecoverable numerical difficulties. |
|
13 |
Unable to satisfy optimality tolerances; a sub-optimal solution is available. |
|
14 |
An asynchronous optimization call was made, but the associated optimization run is not yet complete. |
|
15 |
User specified an objective limit (a bound on either the best objective or the best bound), and that limit has been reached. |
|
16 |
Optimization terminated because the work expended exceeded the value specified in the WorkLimit parameter. |
|
17 |
Optimization terminated because the total amount of allocated memory exceeded the value specified in the SoftMemLimit parameter. |