Initializing help system before first use

problem.iisnext

Purpose
Continues the search for further Irreducible Infeasible Sets (IIS), or calls problem.iisfirst if no IIS has been identified yet. The returned value is 0 in case of success; 1 if no more IIS could be found, or problem is feasible if no problem.iisfirst call preceded; or 2 in case of an error.
Synopsis
status_code = problem.iisnext()
Example
This looks for a further IIS. 
while p.iisnext() == 0:
   [...] # do something with the iis
Further information
1. A model may have several infeasibilities. Repairing a single IIS may not make the model feasible. For this reason the Optimizer attempts to find an IIS for each of the infeasibilities in a model. Call the problem.iisnext function repeatedly, or use the problem.iisall function to retrieve all IIS at once.
2. This function is not affected by the control MAXIIS.
3. If the problem has been modified since the last call to problem.iisfirst or problem.iisnext, the generation process has to be started from scratch.
Related topics
problem.getiisdata, problem.iisall, problem.iisclear, problem.iisfirst, problem.iisisolations, problem.iisstatus, problem.iiswrite.

Parent Topic Xpress problem methods

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