[Coin-discuss] User exit tests in Cbc?

[acw at ascent.com]

I was unclear, but you got my meaning.  Actually, we are measuring the 
amount of virtual memory available, and exiting if it gets close to zero.

Thank you for the pointer to CbcEventHandler.  I'll check it out.



John J Forrest <jjforre at us.ibm.com> 
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05/05/2006 02:01 PM
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Re: [Coin-discuss] User exit tests in Cbc?







I am not sure how to recover from a crash.  Are you checking memory usage 
and then exiting if it gets close to 2Gb? 

If so the simplest thing to do is to derive an event handler from 
CbcEventHandler to do the checking and return stop if too much memory 
being used.  You use passIn EventHandler to tell CbcModel to use your one. 


John Forrest 


acw at ascent.com 
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05/05/2006 12:29 PM 

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[Coin-discuss] User exit tests in Cbc?









Our application using COIN/Cbc is going very well.  We have successfully 
ported to Windows and integrated an only-slightly-tweaked Cbc solver with 
the rest of our application. 

Recently, however, we encountered a case for which the solver ran out of 
memory and crashed ignominiously in the middle of a run.  (In the 
benighted world of 32-bit Windows, a process's address space is limited to 
about 2Gb.)  We are, therefore, adding an extra exit test to the main loop 
in CbcModel::branchAndBound.  It isn't very tricky.  But we would like to 
do it without modifying CbcModel.cpp any more than is absolutely 
necessary, so that we can stay synchronized with the main-branch sources 
as easily as possible.  So this led us to consider adding a little user 
hook to the exit tests.  Perhaps just after "!stoppedOnGap && 
!eventHappened" we could add "&& !userExitTest()". 

Have the Cbc developers considered making this kind of user exit hook 
available?  What would you consider the most "Cbc-y" way to do it? 

Thanks for your thoughts._______________________________________________
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