Originally posted by: BCDS_Daniel_Underwood

Suppose a file named myProblem.mod exists with the following contents:

range N = 1..4;
 
int c[N][N]= [[99999, 7, 6, 3],
              [3, 99999, 6, 9],
              [2, 3, 99999, 1],
              [7, 9, 4, 99999]];
 
dvar boolean x[N][N];
 
minimize sum(i in N) sum(j in N) c[i][j]*x[i][j];
subject to {
 
 forall(i in N) sum(j in N) x[i][j]==1;
 forall(j in N) sum(i in N) x[i][j]==1;
}

To solve the model, I enter the following at the command line:

$ oplrun myProblem.mod

This solves my model and displays, among other information, the optimal objective value. However, this does not display the optimal solution. How can I modify the above command, or the code inside myProblem.mod, such that the optimal solution (the optimal values of the decision variables) is also displayed on the screen (standard output)?
#DecisionOptimization
#OPLusingCPLEXOptimizer

Originally posted by: SystemAdmin

You could do so by adding a post-processing block at the end of the mod file after the 'subject to' block, which can include the required print statements:

execute DISPLAY_RESULTS{
  writeln("Optimal Values:");
  for(var i in N){
    for(var j in N){
      writeln("x["+i+"]["+j+"]="+x[i][j]);
    }
  }
}

Invoke the model as before($oplrun myProblem.mod).

More on preprocessing and postprocessing using OPL scripts can be found in the following documentation link:
http://publib.boulder.ibm.com/infocenter/cosinfoc/v12r3/index.jsp?topic=%2Filog.odms.ide.help%2FContent%2FOptimization%2FDocumentation%2FOptimization_Studio%2F_pubskel%2Fps_opl_Language668.html
#DecisionOptimization
#OPLusingCPLEXOptimizer