Questions tagged [irreducible-infeasible-subset]
For questions on subsets of constraints of an infeasible mathematical program whose (strict) subsets are feasible.
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Gurobipy MILP model comes infeasible yet can't compute IIS because "the model is feasible"
I build a MILP model by Pyomo and use Gurobi 9.0.3 as solver.
When the model comes infeasible, I try to use pyomo.contrib.iis.iis.write_iis
to compute infeasible ...
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Question about IIS output in Pyomo, Gurobipy
These days I try to build a Gurobipy optimization model by Pyomo and I met a problem about outputing IIS file.
I use
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How to cmpute IIS using the Or-Tools solver?
I'm trying to solve a MIP using Google Or-Tools, but it's showing that the model is infeasible. I'd like to know if there is a convenient way to analyze which constraint or variable bounds are causing ...
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Which solvers provide an IIS feature?
I am well aware that commercial solvers CPLEX and GUROBI provide an IIS (irreducible infeasible set) feature. @batwing mentions FICO Xpress in the comment section as well, and @RobPratt mentions SAS.
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Minimal infeasible constraint set
Many modern SAT and SMT solvers offer a feature where they can report why a problem is unsatisfiable, something called an "unsat core."
Are there any optimization solvers (in my case, ...
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How to solve infeasible cplex model in GAMS?
I am facing this kind of error
"Row 'eq1(14)' infeasible, all entries at implied bounds"
in a problem that a GAMS script gets data from MATLAB. I have seen some posts about conflict ...
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How to see fix constraint violations found with IIS
I'm running a simple MCNF model to see if my network is balanced. I'm using Gurboi in Python and with the IIS I can see that there are 2 constraint violations making it infeasible. How do I fix these ...
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4
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How to see constraint violation for network flow problem
I am testing to see if my network is balanced as part of a larger protection-interdiction-restoration problem. To do this, I'm solving the problem as a minimum cost network flow problem to see if the ...
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Pyomo: Compute IIS, remove corresponding constraint and resolve
I am using pyomo together with a bunch of solvers (gurobi, cbc, etc.).
I am able to compute the IIS (with gurobi, not cbc), and write it in a *.ilp file.
What I ...
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2
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Compute Irreducible Infeasible Set (IIS) in Pyomo
I am using Pyomo together with Gurobi (and other solvers such as cbc). I am trying to compute an Irreducible Infeasible Set (ISS).
In Pyomo documentation, ...
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Is it possible to identify all possible Irreducible Infeasible Sets (IIS) for an infeasible Integer Linear Programming problem? (ILP)?
For an Integer Linear Programming problem (ILP), an irreducible infeasible set (IIS) is an infeasible subset of constraints, variable bounds, and integer restrictions that becomes feasible if any ...
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How to check infeasibility with conflict refiner (docplex mixed integer programming )?
Please, if someone can give me an example of the application of conflict refiner, I have already read the documentation but I did not understand how to use it well.
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Is there any automatic way to spot contradictory constraints in linear programming?
Let's have the following trivial linear program: \begin{align}\max&\quad z=20A+30B\\\text{s.t.}&\quad A\le60\\&\quad B\le50\\&\quad A+2B\ge220\\&\quad A,B\ge0\end{align}
It's easy ...
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How to know which constraint in CP-SAT did not meet the feasibility gap
Is there any systematic way to retrieve some information on the constraint that caused infeasibility in Or.Tools CP-SAT?
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Computational complexity to compute an IIS
How hard is it to compute an irreducible infeasible subset (IIS) for a linear program? What about an integer program (e.g., removing the integrality constraint on a single variable may be enough to ...
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Is the Irreducible Infeasible Subset (IIS) of an LP unique?
The IIS is a standard part of most modern solvers, but is it unique for an LP? My intuition tells me that it should be, but I could find any proof.
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