Originally posted by: MohamedAbuSharkh

Hi ,

I am new to optimization studio and i am facing a small issue. I am getting an "Infeasible solution " result and i was hoping to look into the detailed model to resolve that,

is there a way to extract the prodced model from the OPL program in a way similar to ExtractModel method ? or can i use the same method within the OPL code,

I tried adding extract model command in a script block-excute { }    before the constraint block but it didn't work correctly.

I am using optimization studio 12.5

The code that is causing the infeasibility looks like this

 forall(r in requests)
         {  
            forall(s in server_nonode)
              {
                       if( isSource[r][v]==1)
(sum(l in links) (Y[r][l]*linkOutserver[l][s]) - sum (l in links) (Y[r][l]*linkInserver[l][s])) == X[v][s];
               
             }
          }
      }

                             
forall(v in VM_no_node)
     {
       forall(r in requests)
         {  
            forall(s in server_nonode)
              {
                    if( isDest[r][v]==1)   

                 (sum(l in links) (Y[r][l]*linkOutserver[l][s]) - sum (l in links) (Y[r][l]*linkInserver[l][s])) ==0 (-1*X[v][s]);
                
             }
          }
      }  
 

Your help is highly appreciated guys

Thanks and Best Regards

First of all, you can analyze infeasibility directly in the IDE, see here. Maybe that is already good enough for you.

In order to write the model to a file you need a main scripting block (after the constraints) that looks like this:

main {
   thisOplModel.generate();
   cplex.exportModel("model.lp");
   cplex.solve();
}

This will write the model in LP format to file "model.lp" before solving it. The 'cplex' variable is an instance of class IloCplex that has other useful methods, see here.

Originally posted by: MohamedAbuSharkh

Thanks Daniel,

I will try both suggestions.

can you please provide the first link again , as it leads to tis page when clicking on it.

Thanks again

I fixed the link in my post. And here it is again: http://pic.dhe.ibm.com/infocenter/cosinfoc/v12r5/index.jsp?topic=%2Filog.odms.ide.help%2FOPL_Studio%2Fusroplide%2Ftopics%2Fopl_ide_relax.html.

Hi,

in your model you should label your constraint.

 forall(r in requests)
         {  
            forall(s in server_nonode)
              {
                       if( isSource[r][v]==1)
(sum(l in links) (Y[r][l]*linkOutserver[l][s]) - sum (l in links) (Y[r][l]*linkInserver[l][s])) == X[v][s];
               
             }
          }
      }

should be rewritten into

 forall(r in requests)
         {  
            forall(s in server_nonode:isSource[r][v]==1)
              {
                    
ctName:(sum(l in links) (Y[r][l]*linkOutserver[l][s]) - sum (l in links) (Y[r][l]*linkInserver[l][s])) == X[v][s];
               
             }
          }
      }

Only labeled constraints will be relaxed in OPL

regards