Originally posted by: hugotorres

Hello,

I'm trying to replicate the idea present on the mulprod example by having a loop where the data is changed and the model is ran again. The problem is that It always finds an issue with the CPLEX basis, saying "warm start preparation failed: 1262". I tried to search if this value had any special meaning but with no sucess. I'll leave my code here and appreciate any help you can give :)

int p=...;
 int m=...;
 
 range pecas=1..p;
 range machines=1..m;
 
 int whours=...;
 
 int processTimes[pecas][machines]=...;
 int availableMachines[machines]=...;
 
 dvar int+ x[pecas][machines];
 dvar int+ y;
 
 dexpr int Z = y;
 
 maximize Z;
 
 subject to
 {
   forall(i in machines)
     sum(j in pecas) (processTimes[j][i]*x[j][i]) <= whours*60*availableMachines[i];
   
   forall(j in pecas)
     sum(i in machines) (x[j][i])-y >= 0;
 }  

main
{
        var status = 0;
        thisOplModel.generate();

        var model = thisOplModel;
        
        var woHours = model.whours;
        var best;
        var curr = Infinity;
        var basis = new IloOplCplexBasis();
        
        while(woHours != 0)
        {
          best = curr;
      writeln("Solve with working hours = ",woHours);
     if (cplex.solve()) {
      curr = cplex.getObjValue();
      writeln();
      writeln("OBJECTIVE: ",curr);
        }
    
    else {
      writeln("No solution!");
      break;
    } 
    
    if ( !basis.getBasis(cplex) ) {
      writeln("warm start preparation failed: ",basis.status);
      break;
    }

    // prepare next iteration
    var def = produce.modelDefinition;
    var data = produce.dataElements;
      
    if ( produce!=thisOplModel ) {
      produce.end();
    }
    
    produce = new IloOplModel(def,cplex);
    woHours--;
    data.whours = woHours;
    produce.addDataSource(data);
    produce.generate();
    
      if ( !basis.setBasis(cplex) ) {
      writeln("warm start ",basis.Nrows,"x",basis.Ncols," failed: ",basis.status);
      break;
    }
  }
  basis.end();
  if (Math.abs(cplex.getObjValue() - 393.5)>=0.01) {
      status = -1;
  }
  if (best != Infinity) {
    writeln("plan = ",produce.Plan);
  }
  if ( model!=thisOplModel ) {
    model.end();
  }

  status;
} 

Originally posted by: hugotorres

No one? I really need some help on this :S

Originally posted by: Stanko_86

The problem is here:

    // prepare next iteration
    var def = produce.modelDefinition;
    var data = produce.dataElements;

You used here variable "produce" (probably copied from multiprod example), 
but you should use "model" instead, because the model has been defined above.

Originally posted by: hugotorres

Changed that and all the instances of Produce to Model but the problem keeps the same =\ 

Originally posted by: Stanko_86

It is not allowed to have integer variables when you are using IloOplCplexBasis. It is applicable only for linear programming models.

As @AlexFleischer a1d4492b-6cf8-402d-ae3c-dd656c427dc7 suggests, the example how to use warm start in MIP problem is given in opl\examples\opl\warmstart

​

Originally posted by: hugotorres

I tried to adapt that code to my situation and got an error saying "Expected CPLEX, got CP". I tried to remove the line of "using CP" but if I do, CPLEX won't recognize the .dat file, and consequently won't have the values needed for solving this. Are both of these things incompatible or there's a way to work around this?

Hi,

can you post all your models and data files ?

regards

Originally posted by: hugotorres

I ended up solving that problem. Right now my main issue is that I get an error saying "unknown property addDataSource". 

 

/*********************************************
 * OPL 12.6.3.0 Model
 * Author: Hugo
 * Creation Date: 16 de Mar de 2016 at 18:56:26
 *********************************************/

//using CP;
 
 int p=...;
 int m=...;
 
 range pecas=1..p;
 range machines=1..m;
 
 int whours=...;
 
 int processTimes[pecas][machines]=...;
 int availableMachines[machines]=...;
 
 dvar int+ x[pecas][machines];
 dvar int+ y;
 
 maximize y;
 
 subject to
 {
   forall(i in machines)
     sum(j in pecas) (processTimes[j][i]*x[j][i]) <= whours*60*availableMachines[i];
   
   forall(j in pecas)
     sum(i in machines) (x[j][i])-y >= 0;
 }  

main
{
  var def = thisOplModel.modelDefinition;
  var data = thisOplModel.dataElements;
  def.addDataSource(data);   
  var cplex1 = new IloCplex();
  var opl1 = new IloOplModel(def, cplex1);
  
  opl1.generate();
                if ( cplex.solve() ) 
                        {
                                curr = cplex.getObjValue();
                                writeln();
                                writeln("OBJECTIVE: ",curr);
                        } 
                else 
                        {
                                writeln("No solution!");
                        }                     
 }                     

/*********************************************
 * OPL 12.6.3.0 Data
 * Author: Hugo
 * Creation Date: 16 de Mar de 2016 at 18:56:26
 *********************************************/

p=2;
m=2;

whours = 8;

 SheetConnection mysheet("dataSheet.xlsx");
 
 processTimes from SheetRead(mysheet,"processTimes");
 availableMachines from SheetRead(mysheet,"availableMachines");
 
 x to SheetWrite(mysheet,"File");

Originally posted by: Stanko_86

Hi,

instread of 

  def.addDataSource(data);

try:

  opl1.addDataSource(data); // this goes after opl1 has been defined

Originally posted by: hugotorres

Worked! Thank you so much! Since this is getting far from the original question, I'll mark this as solved and start another thread if I need to :)