problem.iisstatus
problem.iisstatus |
Purpose
Returns statistics on the Irreducible Infeasible Sets (IIS) found so far by
problem.iisfirst,
problem.iisnext, or
problem.iisall. The returned value is the number of IISs found so far.
Synopsis
iiscount = problem.iisstatus (rowsizes, colsizes, suminfeas, numinfeas)
Arguments
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rowsizes
|
Number of rows in the IISs.
|
|
colsizes
|
Number of bounds in the IISs.
|
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suminfeas
|
The sum of infeasibilities in the IISs after the first phase simplex.
|
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numinfeas
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The number of infeasible variables in the IISs after the first phase simplex.
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Example
This example first retrieves the number of IISs found so far, and then retrieves their main properties. Note that the arrays have size
count+1, since the first index is reserved for the initial infeasible subset.
rs = [] cs = [] ninf = [] p.iisstatus (rs, cs, numinfeas = ninf) # suminf is not of interest
Further information
1. The arrays are
0 based, index 0 corresponding to the initial infeasible subproblem.
2. The arrays may be
None if not required.
3. For the initial infeasible problem (at position 0) the subproblem size is returned (which may be different from the number of bounds), while for the IISs the number of bounds is returned (usually much smaller than the number of columns in the IIS).
4. Note that the values in
suminfeas and
numinfeas heavily depend on the actual basis where the simplex has stopped.
5.
iiscount is set to
-1 if the search for IISs has not yet started.
Related topics
problem.getiisdata,
problem.iisall,
problem.iisclear,
problem.iisfirst,
problem.iisisolations,
problem.iisnext,
problem.iiswrite.