Originally posted by: Amira Hijazi

Hi everyone,

I am trying to apply benders decomposition in my model using annotation with blocks of variables. 

This is my main part in the model:

main{
thisOplModel.generate();

var masterDef = thisOplModel.modelDefinition;
var masterElts = thisOplModel.dataElements;

// use annotation with blocks of variables.
// if partitioning is bad, then an error will be raised by CPLEX...
var subCplex3 = new IloCplex();
var subOpl3 = new IloOplModel(masterDef, subCplex3);
subOpl3.addDataSource(masterElts);
subOpl3.generate();
subCplex3.bendersstrategy = 1;

subCplex3.newLongAnnotation("cpxBendersPartition");

subCplex3.setLongAnnotations("cpxBendersPartition", subOpl3.y, subOpl3.bendersPartition);
subCplex3.solve();

writeln(subCplex3.getObjValue());

subCplex3.delLongAnnotation("cpxBendersPartition");

subOpl3.end();

subCplex3.end();

}

and this is my partitioning:

int bendersPartition[i in I][scenario_no in scenario_index] = scenario_no;

I am not sure what is missing or wrong? 

I keep getting an erro "invalid benders decomposition? Do i need to add any thing else like cuts?