Hi

sub.mod

int y[1..2][1..2]=...;

execute
{
writeln("y=",y);
}

dvar float x;

maximize x;
subject to {
  x<=sum(i in 1..2, j  in 1..2) y[i][j];
}

then in a an other .mod file

int a[1..2][1..2];

main {
  var source = new IloOplModelSource("sub.mod");
  var cplex = new IloCplex();
  var def = new IloOplModelDefinition(source);
 
 
 
  for(var k=11;k<=15;k++)
  {
  var opl = new IloOplModel(def,cplex);
 
 
    
  var data2= new IloOplDataElements();
 
  data2.y=thisOplModel.a;
  data2.y[1][1]=k;
  opl.addDataSource(data2);
 
  opl.generate();

  if (cplex.solve()) {
     writeln("OBJ = " + cplex.getObjValue());
  } else {
     writeln("No solution");
  }
  data2.end();
 opl.end();
 
 
}  
 
}

gives

y= [[11 0]
         [0 0]]
OBJ = 11
y= [[12 0]
         [0 0]]
OBJ = 12
y= [[13 0]
         [0 0]]
OBJ = 13
y= [[14 0]
         [0 0]]
OBJ = 14
y= [[15 0]
         [0 0]]
OBJ = 15

regards

Alex Fleischer

PS:

Many how to with OPL at https://www.linkedin.com/pulse/how-opl-alex-fleischer/

Many examples from a very good book : https://www.linkedin.com/pulse/model-building-oplcplex-alex-fleischer/

Making optimization simple : https://www.linkedin.com/pulse/making-decision-optimization-simple-alex-fleischer/

Originally posted by: ShafiAhad

Hello Alex,

Thanks for your reply. 

But when I am trying to run this I am getting following error "Scripting runtime error: Element "a" does not exist in OPL model.."

And this is understandable because, int a[1..2][1..2]=...; is outside of main{} and it won't recognize it. can you please suggest any solution??

I am attaching the .mod an d.dat file.

Thanks in advance..!!

Hi

oplrun main.mod works

regards

Originally posted by: ShafiAhad

Hello Mr. Alex,

This really helps. Thanks a lot. 

And just a note that I am trying to learn and use OPL to solve a big complex problem. I might contact you in future as well. Hope I'll get help from you. I really appreciate your help.

Thanks again.

Shafi

Originally posted by: ShafiAhad

Hello Mr. Alex,

I am trying to solve a model in iteration using flow control (main). I can solve the problem without issue but the problem I am facing is displaying the values of decision variable.

the command "writeln("OBJ = ",cplex.getObjValue());" displays the value of objective function. 

but when I try to print value of decision variable it is showing error. for example if I have a decision variable 'x' and i write" writeln("X= ",x);" it is showing "Scripting runtime error: unknown variable 'x'."

can you please help me with the right function to write the value of decision variables? 

Thanks in advance.

Originally posted by: ShafiAhad

Hello Mr. Alex,

I am trying to solve a model in iteration using flow control (main). I can solve the problem without issue but the problem I am facing is displaying the values of decision variable.

the command "writeln("OBJ = ",cplex.getObjValue());" displays the value of objective function. 

but when I try to print value of decision variable it is showing error. for example if I have a decision variable 'x' and i write" writeln("X= ",x);" it is showing "Scripting runtime error: unknown variable 'x'."

can you please help me with the right function to write the value of decision variables? 

Thanks in advance.

Hi,

ig you go back to the example I wrote,

writeln("x in the main = ",opl.x);

would do the job.

If I call

 

    int a[1..2][1..2];

    main {
      var source = new IloOplModelSource("sub.mod");
      var cplex = new IloCplex();
      var def = new IloOplModelDefinition(source);
     
     
     
      for(var k=11;k<=15;k++)
      {
      var opl = new IloOplModel(def,cplex);
     
     
        
      var data2= new IloOplDataElements();
     
      data2.y=thisOplModel.a;
      data2.y[1][1]=k;
      opl.addDataSource(data2);
     
      opl.generate();

      if (cplex.solve()) {
         writeln("OBJ = " + cplex.getObjValue());
         writeln("x in the main = ",opl.x);
      } else {
         writeln("No solution");
      }
      data2.end();
     opl.end();
     
     
    }  
     
    }

then I get

y= [[11 0]
         [0 0]]
OBJ = 11
x in the main = 11
y= [[12 0]
         [0 0]]
OBJ = 12
x in the main = 12
y= [[13 0]
         [0 0]]
OBJ = 13
x in the main = 13
y= [[14 0]
         [0 0]]
OBJ = 14
x in the main = 14
y= [[15 0]
         [0 0]]
OBJ = 15
x in the main = 15

regards

https://www.linkedin.com/pulse/how-opl-alex-fleischer

Originally posted by: ShafiAhad

Thank you very much. Really appreciate it.

Originally posted by: ShafiAhad

Hello Mr. Alex,

Hope you are doing good. 

to solve an OPL model I need to read data from a txt file within a main block and use that data to calculate some other parameter. I want to read the data in a loop (the data file are named in an orderly manner like data1.txt; data2.txt; data3.txt etc). I was trying to use below code but it's not working.

execute READ_FROM_FILE {
    var f = new IloOplInputFile();
    f.open("data.txt");
    read(f, "data", data);
    f.close();
    writeln("DONE");
    writeln(data);
    
}

I would really appreciate your help. Thanks in advance

Hi,

a small example at https://www.ibm.com/developerworks/community/forums/html/threadTopic?id=77777777-0000-0000-0000-000014603725&ps=25

regards