Originally posted by: Bo7

Hello,
I'm working with c# and i use indicators but i can't find how to write the formulation below with c# because it uses the indicators implicitly( with the methods like ifThen Or And)

Here is the example that i want to write in LP format file:
alph10 = 1 -> d8 - d5 + 0P <= 3
d8 - d5 + 0P >= 1
alph11 = 1 -> d8 - d6 + 0P <= 5
d8 - d6 + 0P >= 3
alph12 = 1 -> d8 - d7 + 0P <= 3
d8 - d7 + 0P >= 1
alph10 + alph11 + alph12 = 1
what instruction and methods with c# should i use to have the same formulation.

Thank you very much in advance
#CPLEXOptimizers
#DecisionOptimization

Originally posted by: SystemAdmin

As in other flavors (C++, Java) of Concert you create this kind of constraint using the IfThen, Or and And member functions of class Cplex.
Unfortunately, it seems that IfThen is not documented in the reference documentation (but And and Or are).
However, IfThen works exactly like in the other Concert APIs, so you may check there. For your first constraint the code would look like this

using ILOG.Concert;
using ILOG.CPLEX;
 
public class Indicator {
   public static void Main(string[] args) {
      try {
         Cplex cplex = new Cplex();
 
         INumVar alph10 = cplex.NumVar(0, 1, "alph10");
         INumVar d5     = cplex.NumVar(0, 1, "d5");
         INumVar d8     = cplex.NumVar(0, 1, "d8");
         INumVar OP     = cplex.NumVar(0, 1, "OP");
 
         cplex.Add(cplex.IfThen(cplex.Eq(alph10, 1.0),
                                cplex.Le(cplex.Sum(cplex.Diff(d8, d5), OP), 3)));
 
         cplex.ExportModel("indicator.lp");
         cplex.End();
      }
      catch (ILOG.Concert.Exception e) {
         System.Console.WriteLine("Concert exception caught '" + e + "' caught");
      }
   }
}

#CPLEXOptimizers
#DecisionOptimization

Originally posted by: Bo7

ok thank you i will try this
#CPLEXOptimizers
#DecisionOptimization