search

scipopt / scip

SCIP - Solving Constraint Integer Programs
Other
369 stars 63 forks source link

Remove a node from node pool #33

Closed dxyzx0 closed 1 year ago

dxyzx0 commented 1 year ago

I have 2 questions:

  1. Is it possible to remove a node from the node pool during the solving process safely? I want to remove a subtree from the solving process.
  2. If so, is it possible to do that in fscip? Since fscip is a parallel version of scip, should I use some mutex/lock to accomplish this?

Thanks.

ambros-gleixner commented 1 year ago
  1. Yes, absolutely, the UG framework does that, e.g., if you want to look at code to achieve it.
  2. I suppose you mean remove "UG nodes". I guess so, but for that I would refer you to inquire at ug@zib.de. This would also be the best place to ask about 1.
dxyzx0 commented 1 year ago

@ambros-gleixner Thanks, is there a proper way to ask questions about ug framework except via e-mail?

dxyzx0 commented 1 year ago
  1. Yes, absolutely, the UG framework does that, e.g., if you want to look at code to achieve it.
  2. I suppose you mean remove "UG nodes". I guess so, but for that I would refer you to inquire at ug@zib.de. This would also be the best place to ask about 1.

Yes, I want to accomplish things similar to UG framework. However, the code of UG is too long to read and has limited doc. I have 2 additional questions:

  1. What's the difference between UG node and scip node?
  2. Is it possible to directly achieve this functionality just in scip? I mean, at some point, I can safely remove the node without destroy the solving process.
ambros-gleixner commented 1 year ago

To enquire about UG the mail ug@zib.de is the point of contact, or you can write to Yuji Shinano directly, same thing. He would be the most competent person to answer your questions. You can certainly achieve this safely within SCIP, e.g., by updating the lower bound to +infinity.