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IISMethod
Selects method used to compute IIS
| Type: | int | |
|---|---|---|
| Default value: | -1 | |
| Minimum value: | -1 | |
| Maximum value: | 3 |
Chooses the IIS method to use. To compute an IIS for an LP, it is sufficient to solve an LP with dimensions similar to the dual of the original model. If the solve time for that LP is excessive, setting the IISMethod parameter to 1 may offer a faster alternative; other settings do not alter the default approach for infeasible LPs. For MIPs, filtering of constraints and variables is required, which involves solving a series of related MIP subproblems. Methods 0-2 all use filtering techniques. Method 0 is often faster than method 1, but may produce a larger IIS. Method 2 ignores the bound constraints. It therefore tends to be faster than methods 0-1, but will fail if these bounds are necessary to make the problem infeasible. Method 3 will return the IIS for the LP relaxation of a MIP model if the relaxation is infeasible, even though the result may not be minimal when integrality constraints are included. The default value of -1 chooses automatically.
For examples of how to query or modify parameter values from our different APIs, refer to our Parameter Examples.
