Originally posted by: CplexUser1453

Hello

I am trying to see if I can implement a decomposition using OPL script and I have run into the following problem: I need to modify non scalar data.

I have found examples of how to modify scalar data (http://pic.dhe.ibm.com/infocenter/cosinfoc/v12r4/index.jsp, https://www.ibm.com/developerworks/community/forums/html/topic?id=243675ee-3045-41b5-ada9-d1613686b44c&ps=25) but somehow I am incapable of modifying non scalar stuff. The link above says :

"Only external data can be modified by script. [...] So you would need to create a .dat file that contains the data to update"

However, I am getting an error when supplying the data that is supposed to be updated. Here is a very simple example :

var m1Source = new IloOplModelSource("model.mod");
var m1Cplex = new IloCplex();
var m1Def = new IloOplModelDefinition(m1Source);
var m1Opl = new IloOplModel(m1Def,m1Cplex);

var defaultData           = new IloOplDataSource("defaultData.dat");

var subProblemData = new IloOplDataSource("subProblemData.dat");

m1Opl.addDataSource(defaultData);

m1Opl.addDataSource(subProblemData);

I get an error on the last line that the data element that I want to update has already been defined ("La donnée elementaire "X" a déjà été définie.)

subProblemData.dat contains the following data :

X =   [1, 2, 3, 4];

while the original data is a

{int} X

initialized with values [1, 2, 3, 4,5,6]

(Obviously,  my example is just an illustration and may not make much sense by itself  - what I am really trying to do is decomposing a large MILP problem that is defined in a single .mod file. The decomposition requires updating the non scalar data and I would like to do it without touching the .mod file)

Is there any way to solve this problem, or what I am trying to do is not possible with OPL script?

Thanks a lot!

Hi,

let me give you a small example.

Sub model sub.mod

float maxOfx = ...;
{int} y=...;

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

dvar float x;

maximize x;
subject to {
  x<=maxOfx+sum(i in y)i;
}

and then the main .mod is

{int} s={};

main {
  var source = new IloOplModelSource("sub.mod");
  var cplex = new IloCplex();
  var def = new IloOplModelDefinition(source);
  var opl = new IloOplModel(def,cplex);
 
 
  for(var k=11;k<=15;k++)
  {
  var opl = new IloOplModel(def,cplex);
    
  var data2= new IloOplDataElements();
  data2.maxOfx=k;
data2.y=thisOplModel.s;
data2.y.add(6);
data2.y.add(k);
  opl.addDataSource(data2);
  opl.generate();

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

and the display is

y= {6 11}
Tried aggregator 1 time.
LP Presolve eliminated 1 rows and 2 columns.
All rows and columns eliminated.
Presolve time = 0.00 sec. (0.00 ticks)
OBJ = 28
y= {6 11 12}
Tried aggregator 1 time.
LP Presolve eliminated 1 rows and 2 columns.
All rows and columns eliminated.
Presolve time = 0.02 sec. (0.00 ticks)
OBJ = 41
y= {6 11 12 13}
Tried aggregator 1 time.
LP Presolve eliminated 1 rows and 2 columns.
All rows and columns eliminated.
Presolve time = 0.00 sec. (0.00 ticks)
OBJ = 55
y= {6 11 12 13 14}
Tried aggregator 1 time.
LP Presolve eliminated 1 rows and 2 columns.
All rows and columns eliminated.
Presolve time = 0.00 sec. (0.00 ticks)
OBJ = 70
y= {6 11 12 13 14 15}
Tried aggregator 1 time.
LP Presolve eliminated 1 rows and 2 columns.
All rows and columns eliminated.
Presolve time = 0.02 sec. (0.00 ticks)
OBJ = 86

I hope this helps

Regards