Exp(an equation)

Answered

Hadi Askaripoor

February 10, 2024 02:05

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for (Data d:rs.getData()) {
             
             List<Data_Out> listofDouts = new ArrayList<Data_Out>();
             
             for(Data_Out dout:rs.getData_out()) {
                 if(dout.getDataout_has()== d) {
                     listofDouts.add(dout);
                 }
                 
                 GRBLinExpr expr_reliab = new GRBLinExpr();
                 for(int i=0; i<listofDouts.size(); i++) {
                     
                     expr_reliab.addTerm(listofDouts.get(i).getData_out_has_link().getFailure_Rate_FIT(), 
                             listofDouts.get(i).getData_out_gurobi());
                 }

                GRBVar exp_lambda_decision = model.addVar(0.0, GRB.INFINITY, 0.0, GRB.CONTINUOUS, "exp_lambda_decision");
                GRBGenConstr test = model.addGenConstrExp(exp_lambda_decision, expr_reliab, "exp_lambda", "test");  

}

Hello,

I am wondering how I can exp the expr_reliab (e^(expr_reliab)) in the code above. model.addGenConstrExp doesn't work as it needs two GRB Vars.

Thanks!

Hadi 

 

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  Riley Clement

  • Gurobi Staff

  February 10, 2024 16:46

  Hi Hadi,

  If you create an auxiliary variable "reliab", (noting that default lower bound is 0, so change it if need be), add a constraint reliab == expr_reliab, then you can use

  GRBGenConstr test = model.addGenConstrExp(exp_lambda_decision, reliab, "exp_lambda", "test");  
  
  }

  Note, allowing expressions in the arguments is in our roadmap for development but as of right now this is how to do it.

  - Riley

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  Hadi Askaripoor

  February 13, 2024 02:34

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  Dear Riley,

  Thanks for your reply!

  I will test it and get back to you.

  Best,

  Hadi

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