The @STATUS Function

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The @STATUS function returns the status of the solution process using the following codes:

@Status Code	Interpretation
0	Global Optimum - The optimal solution has been found, subject to current tolerance settings.
1	Infeasible - No solution exists that satisfies all constraints.
2	Unbounded - The objective can be improved without bound.
3	Undetermined - The solution process failed.
4	Feasible - A feasible solution was found that may, or may not, be the optimal solution.
5	Infeasible or Unbounded - The preprocessor determined the model is either infeasible or unbounded. Turn off presolving and re-solve to determine which.
6	Local Optimum - Although a better solution may exist, a locally optimal solution has been found.
7	Locally Infeasible - Although feasible solutions may exist, LINGO was not able to find one.
8	Cutoff - The objective cutoff level was achieved.
9	Numeric Error - The solver stopped due to an undefined arithmetic operation in one of the constraints.

In general, if @STATUS does not return a code of 0, 4, 6, or 8, then the solution is of little use and should not be trusted. In many cases LINGO will not even export data to the @POINTER memory locations if @STATUS does not return one of these three codes.