Knowing the value of some of variables (when we solve a model from a file)

[s. sadeghi]

 
 I load and solve a model from a file, for example my model is as follow:
 
Maximize
  x + y + 2 z
Subject To
 c0: x + 2 y + 3 z <= 4
 c1: x + y >= 1
Bounds
Binaries
 x y z
End

 I solve this model as a file according to following source code:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
#include <fstream>
#include "gurobi_c++.h"
using namespace std;

int main()

 ifstream infile;
infile.open("my model.lp");
  try {

    GRBEnv env = GRBEnv();
    GRBModel model = GRBModel(env,"my model.lp");

    model.optimize();

    int optimstatus = model.get(GRB_IntAttr_Status);

    if (optimstatus == GRB_OPTIMAL) {
      double objval = model.get(GRB_DoubleAttr_ObjVal);
      cout << "Optimal objective: " << objval << endl;
    } else if (optimstatus == GRB_INFEASIBLE) {
      cout << "Model is infeasible" << endl;

   
    } else if (optimstatus == GRB_UNBOUNDED) {
      cout << "Model is unbounded" << endl;
    } else {
      cout << "Optimization was stopped with status = "
           << optimstatus << endl;
    }

  } catch(GRBException e) {
    cout << "Error code = " << e.getErrorCode() << endl;
    cout << e.getMessage() << endl;
  } catch (...) {
    cout << "Error during optimization" << endl;
  }
  return 0;
}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

 This source code just give me the value of objective function, but I want to know the value of some of variables (for example the value of y in my model). What command should I add to my source code?
 

[Renan Garcia]

Try the GRBModel::getVars() (see http://www.gurobi.com/documentation/7.5/refman/cpp_grbmodel_getvars.html) or GRBModel::getVarByName() (see http://www.gurobi.com/documentation/7.5/refman/cpp_grbmodel_getvarbyname.html) methods, along with the X attribute (see http://www.gurobi.com/documentation/7.5/refman/x.html#attr:X).

You'll find several examples of how to query for attributes at http://www.gurobi.com/documentation/7.5/refman/attribute_examples.html#sec:AttributeExamples and http://www.gurobi.com/resources/examples/example-models-overview.

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[s. sadeghi]

Thank you for your explanation.