Originally posted by: saeedmarvi

Hi,

I have a MIP model in OPL and I can load it in java using OPL interface (using IloOplFactory, IloOplModel etc.) and running that OPL model from java works fine. I would like to be able to stop the run and resume it later using MIPstarts. I found this note http://www-01.ibm.com/support/docview.wss?uid=swg21400014 . Could any one help me finding a code EXAMPLE on this. I have read the documentation and know the statements, but I really need an EXAMPLE to see how to use these methods, readMIPStarts and writeMIPStarts in java.

Thanks in advance for any EXAMPLE!!!!

Hi

could the 2 links here help ?

https://www.ibm.com/developerworks/community/forums/html/topic?id=77777777-0000-0000-0000-000014868304&ps=25

https://www.ibm.com/developerworks/community/forums/html/topic?id=ea9dd71f-6c81-4daa-8bda-ed71cd29db29&ps=25

Plus be aware that in

IDE and OPL > Optimization Programming Language (OPL) > IBM ILOG Script Reference Manual > OPL Classes

In IloCplex you have now

writeMIPStarts(name, start, nb)

And

regards

Hi,

I was asked recently offline whether this really works, so let me give an example:

The write MIP start :

range r = 1..10;
dvar int+ x[r];
dvar int+ y[r];

minimize
  sum( i in r ) x[i] + sum( j in r ) y[j];
subject to{
  ctSum:    
    sum( i in r ) x[i] >= 10;
  forall( j in r )
    ctEqual:
      y[j] == j;
      
      x[5]==1;
}

main{
  thisOplModel.generate();
  cplex.solve();
  cplex.writeMIPStarts("c:/tam/warmstart/ws.mst",0,1);
writeln(thisOplModel.printSolution());
 
}

and the read part:

range r = 1..10;
dvar int+ x[r];
dvar int+ y[r];

minimize
  sum( i in r ) x[i] + sum( j in r ) y[j];
subject to{
  ctSum:    
    sum( i in r ) x[i] >= 10;
  forall( j in r )
    ctEqual:
      y[j] == j;
}

main{
  thisOplModel.generate();  
  cplex.readMIPStarts("c:/tam/warmstart/ws.mst");
  cplex.solve();   
  writeln(thisOplModel.printSolution());

 
}

regards

Originally posted by: Yasmina

Hi,

The answer of AlexFleischer is exactly what I am looking for. I am using OPL scripting, with Cplex version 12.6.0.0 , but the writeMIPStarts method is unknown : "unknown property WriteMIPStart". I tried with both small and capital w : WriteMIPStart and writeMIPStart. Do I need a more recent version of Cplex to have this method working ?

Thanks for your help,

Yasmina

Hi,

can t you move to CPLEX 12.7 ?

regards

Originally posted by: Yasmina

Yes, I upgraded to 12.7 and it works.

Thanks,

Yasmina