[Coin-discuss] Removing Deadwood in Bcp

[Jonathan Eckstein]

Francois -- perhaps you know this already, but "top" reports the total 
memory size of the process, including memory in the free pool.  Most 
programs don't return freed memory to the operating system, but just 
keep it in their own free pool.  In unix/linux, I think it is only 
possible to return memory to the OS (via sbrk()) if it is at the end of 
the virtual address space.  Thus, never seeing "top" return smaller 
memory amounts isn't necessarily a sign of a memory problem.  However, 
if the memory reported by "top" always goes up and never stabilizes, 
that might be a sign of a leak.

  -- Jonathan


Francois Margot wrote:
> Laci:
> 
> The RemoveExploredBranches does not create problems, apparently,
> but its efficiency seems quite limited. I have never seen the
> memory usage going down (as reported by top) even when running
> large BC with depth first. Are the generated cuts corresponding
> to deadwood removed from "cuts" in BCP_tm_prob? I can not see where this
> is done. It should not be that hard to do, since it is possible
> to store the index of the node where a cut was generated and remove the cut
> when its "generating node" is removed.
> 
> Francois
> 
>> I have added code that removes the "deadwood" from the search tree, i.e.,
>> immediately removes subtrees that are completely explored. I have done 
>> some
>> quick testing and it seems to work. However, by default it is turned 
>> off, just
>> to make sure that noone's code breaks. I wonder if people could give 
>> it a try
>> and let me know whether it works fine or not. I am interested in both 
>> serial
>> and parallel settings. To enable the feature add
>>     BCP_RemoveExploredBranches 1
>> to your parameter file.
>>
>> --Laci
> 
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