[Dip-tickets] [Dip] #68: LimitTime => infinite loop

[Dip]

#68: LimitTime => infinite loop
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Reporter:  vejlin  |       Type:  defect
  Status:  new     |   Priority:  major 
 Version:  trunk   |   Keywords:        
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 For some LimitTime parameter settings the program enters (what appears to
 be) an infinite loop, printing "Alps0240I" status lines with no progress
 in lower or upper bounds.

 This may be hard to reproduce since it depends on machine speed.

 To reproduce:

 1) Use the MILPBlock example
 2) Use I1_split.mps instance (attached)
 3) Use I1_split.block block file (attached)
 4) Set LimitTime parameter to something low (so that time expires before
 the root node has been fully processed, 10 seconds worked for me)
 5) run program

 This should terminate the program as expected

 6) gradually increase LimitTime parameter and run program

 At some point you see the infinite loop, for me the program terminated as
 expected at LimitTime = 60 seconds, but entered the infinite loop at
 LimitTime settings of 70 seconds and greater. Note that for higher values
 of LimitTime the program functions normally again. On my computer the
 interval in which the infinite loop occurs is quite large and difficult to
 miss.

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Ticket URL: <https://projects.coin-or.org/Dip/ticket/68>
Dip <https://projects.coin-or.org/Dip>
An extensible software framework for implementing decompositon-based bounding algorithms for use in solving large-scale discrete optimization problems.