Originally posted by: a.romero

I'm looking for a way of changing the problem type of an MILP to an LP in the Concert Technology, specifically in the Java SDK.

Is there any way to achieve the same effect of doing "change problem lp" in the interactive optimizer?
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Originally posted by: SystemAdmin

You can use IloConversion (instances of which are created by IloCplex.conversion) to change the type of a variable. If all variables are continuous then Concert technology will consider your model as an LP.
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#DecisionOptimization

Originally posted by: a.romero

Is there any way to get all current variables from an IloCplex? I'm working with different models that don't share a common interface.
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#DecisionOptimization

Originally posted by: SystemAdmin

You can use iterators to identify all the variables. I don't have a link handy, but it has been discussed in other threads. Search the forum for mentions of"linearIterator".

Paul

Mathematicians are like Frenchmen: whenever you say something to them, they translate it into their own language, and at once it is something entirely different. (Goethe)
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Originally posted by: SystemAdmin

Try this thread: https://www.ibm.com/developerworks/forums/message.jspa?messageID=14728966&tstart=0. It shows how to collect all variables in a model.
Depending on where your models come from there may be easier ways. For example, there is an overload of IloCplex::importModel() that returns all variables in one of its arguments.
Moreover, you can use IloIterator to iterate over all variables that were created from a particular IloEnv instance. Together with IloCplex::isExtracted() you can then find all variables that are extracted to a certain IloCplex instance. If you instead use a new instance of IloEnv for each new model then you can use IloIterator just as in the example given in the reference documentation.
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Originally posted by: SystemAdmin

I've posted a Java function that extracts variables from an instance of IloCplex on my blog.

Paul

Mathematicians are like Frenchmen: whenever you say something to them, they translate it into their own language, and at once it is something entirely different. (Goethe)
#CPLEXOptimizers
#DecisionOptimization