Originally posted by: disjunctive

Hi,

There are some related questions with my problem  in the forum but i think i am missing a point. Here is my question:

First, i need solve the master problem to obtain the solutions, say A[i][j] and B[i][k]. Then the subproblem requires these solutions with some modifications. I mean, let X[i] is the needed parameter for the subproblem and for all i, X[i] is calculated as follows:

if A[i][j] equals to 1 for j'th indices then X[i] equals to j.

I couldn't figure out how i can add X[i] to the data of the subproblem. I am using same data file for both problems. Should i identify the X in the data file? I did like this:

var subData=thisOplModel.dataElements;

var subData1= new IloOplDataElements();

for( i in Range)

for(j in Range2)

{ if(A[i][j]==1) { 

subData1.X[i]= masterOpl.A[i][j];

subOpl.addDataSource(subData1) ;}}

subOpl.addDataSource(subData);

When i run the program, it give an error and said there is no X.

If you are able to help me, i will be very grateful.

Thank you.

Hi,

I gave an example at

https://www.ibm.com/developerworks/community/forums/html/topic?id=df612d06-4c0a-4873-b655-42b66422e733&ps=25

sub.mod

float maxOfx = ...;
dvar float x;

maximize x;
subject to {
  x<=maxOfx;
}

and then the main model is

main {
  var source = new IloOplModelSource("sub.mod");
  var cplex = new IloCplex();
  var def = new IloOplModelDefinition(source);
  var opl = new IloOplModel(def,cplex);
 
 var globalValue=0;
 
  for(var k=11;k<=15;k++)
  {
  var opl = new IloOplModel(def,cplex);
    
  var data2= new IloOplDataElements();
  data2.maxOfx=globalValue;

  opl.addDataSource(data2);
  opl.generate();

  if (cplex.solve()) {
     writeln("OBJ = " + cplex.getObjValue());
     globalValue=10+cplex.getObjValue();
  } else {
     writeln("No solution");
  }
data2.end();
 opl.end();
 
 
}  
 
}

and this gives

OBJ = 0
OBJ = 10
OBJ = 20
OBJ = 30
OBJ = 40

regards

Originally posted by: disjunctive

Thank you Alex, but i saw that example. When i write like below, it gives an error and says X does not exist.

for( i in Range)

for(j in Range2)

{ if(A[i][j]==1) { 

subData1.X[i]= j;

subOpl.addDataSource(subData1) ;}}

I define the X in the subproblem.dat file with X=[0,0]. I really don't know what is wrong. Why does it say that X does not exist?

Ok and what about what I suggested at

https://www.ibm.com/developerworks/community/forums/html/topic?id=71ac9d4e-fcc6-4ef9-a7c5-8f2a257e5cdd&ps=25

regards

Originally posted by: disjunctive

Many thanks Alex. I think it worked. However, now it says X is identified before. 

Shouldn't i initialize the parameter in dat. file? I'm sorry for this simple question, but i'm confused.

Thank you again.

Originally posted by: disjunctive

It's done, thanks Alex.

What I want to know is why we need to initialize the X (or any second-stage parameter) with first-stage parameter? When we do like this, we need to add unnecessary parameter X to the first-stage. Am I right? If we don't write like follow: 

subData1.X=masterOpl.X (or another variable with same size)

it says X does not exist. Can we handle this situation in a different way?

Best Regards

Hi

in

var data2= new IloOplDataElements();
data2.y=thisOplModel.a;
data2.y[1][1]=k;

The second and third lines are needed

The first copies the structure and the second the values

This is my way at least!

Regards