[Cbc] Cut Generator Question

[Gabrielle A. Grun]

Hi Kipp,
 
Please note that I was making reference to the stable version that I am using (1.2), not trunk.
 
I know that the idea is to get a "better" integer solution from adding cuts to an existing integer solution.
Infeasibility is quite possible. 

--------------------------------
// continuous is integer
double objectiveValue = newNode->objectiveValue();
setBestSolution(CBC_SOLUTION, objectiveValue,
solver_->getColSolution()) ;

user_function(.......);     /////////add cuts, resolve
if (feasible and all integer variables still have integer values)          //////////some integer variables maynot be "fixed" in the solution or by the added cuts  
     setBestSolution(............);

delete newNode ;
newNode = NULL ;
----------------------------

  setBestSolution(CBC_SOLUTION,objectiveValue,
      solver_->getColSolution()) ;
     lastHeuristic_ = NULL;
     incrementUsed(solver_->getColSolution());
     //assert(nodeInfo->numberPointingToThis() <= 2) ;
     // avoid accidental pruning, if newNode was final branch arm
     nodeInfo->increment();


user_function(.......);     /////////add cuts, resolve
if (feasible and all integer variables still have integer values)          //////////some integer variables maynot be "fixed" in the solution or by the added cuts  
     setBestSolution(............);


     delete newNode ;
     nodeInfo->decrement() ; } }
   /*
   This node has been completely expanded and can be removed from the live
   set.
   */

----- Original Message ----- 
From: Kipp Martin 
To: cbc at list.coin-or.org 
Sent: Saturday, October 16, 2010 3:36 PM
Subject: [Cbc] Cut Generator Question


Hi:

When Cbc is implementing branch and cut, if it finds a node such that 
the continuous relaxation is integer will the node be automatically 
fathomed? Is it possible to tell Cbc to call a user cut generator even 
if it finds an integer node?

Thanks


-- 
Kipp Martin
Professor of Operations Research
and Computing Technology
Booth School of Business
University of Chicago
5807 South Woodlawn Avenue
Chicago, IL 60637
773-702-7456
kmartin at chicagobooth.edu
http://www.chicagobooth.edu/faculty/bio.aspx?person_id=12825325568
http://projects.coin-or.org/OS

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Gabrielle
  ----- Original Message ----- 
  From: Kipp Martin 
  To: cbc at list.coin-or.org 
  Sent: Saturday, October 16, 2010 3:36 PM
  Subject: [Cbc] Cut Generator Question


  Hi:

  When Cbc is implementing branch and cut, if it finds a node such that 
  the continuous relaxation is integer will the node be automatically 
  fathomed? Is it possible to tell Cbc to call a user cut generator even 
  if it finds an integer node?

  Thanks


  -- 
  Kipp Martin
  Professor of Operations Research
  and Computing Technology
  Booth School of Business
  University of Chicago
  5807 South Woodlawn Avenue
  Chicago, IL 60637
  773-702-7456
  kmartin at chicagobooth.edu
  http://www.chicagobooth.edu/faculty/bio.aspx?person_id=12825325568
  http://projects.coin-or.org/OS

  _______________________________________________
  Cbc mailing list
  Cbc at list.coin-or.org
  http://list.coin-or.org/mailman/listinfo/cbc
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