IIS description file in CSV format
This file contains information on a single IIS of an infeasible LP.
| Field | Description |
|---|---|
| Name | Name of a row or column in conflict. |
| Type | Type of conflicting variable (row or column vector). |
| Sense | Sense of conflicting variable: (LE or GE) to indicate or rows. (LO or UP) to indicate lower or upper bounds for columns. |
| Bound | Value associated with the variable, i.e. RHS for rows and bound values for columns. |
| Dual value | The dual multipliers corresponding to the contradiction deducible from the IIS. Summing up all the rows and columns in the IIS multiplied by these values yields a contradicting constraint. This value is negative for <= rows and upper bounds, and positive for >= rows and lower bounds. |
| In iso | Indicates if the row or column is in isolation. |
Note that each IIS may contain a row or column with only on one of its possible senses. This also means that equality rows and columns with both lower and upper bounds, only one side of the restriction may be present. Range constraints in an IIS are converted to greater than or equal constraints.
An IIS often contains other columns than those listed in the IIS. Such columns are free, and have no associated conflicting bounds.
The information contained in these files is the same as returned by the XPRSgetiisdata function, or displayed by (IIS -p).