[gecode-users] High memory consumption during engine declaration

[Guido Tack]

Hi,

if the peak memory is during construction of the engine, it means it
occurs during your problem setup, not during search.  Maybe you can
explain a little more what you're doing there - do you use a lot of
intermediate (STL?) data structures, perform symbolic computations,
read in large files or the like?

Cheers,
   Guido

On Wed, Nov 11, 2009 at 1:10 PM, Christian Schulte <cschulte at kth.se> wrote:
> Hi,
>
> I don't really know what could be the reason without further looking at the
> program. The memory consumed looks massive, actually, almost impossible.
>
> Let's do some math: the search tree has a depth of 45, say with
> recomputation possibly using adaptive recomputation that might be around 10
> spaces stored during search. That is, each space takes almost 100 Meg! A
> thousand variables and 30000 propagators (which propagators do you use?)
> should normally take much less.
>
> So, looks really fishy.
>
> Christian
>
>
>
> --
> Christian Schulte, www.ict.kth.se/~cschulte/
>
>
> -----Original Message-----
> From: users-bounces at gecode.org [mailto:users-bounces at gecode.org] On Behalf
> Of benoit
> Sent: Tuesday, November 10, 2009 11:11 AM
> To: Christian Schulte
> Cc: 'Mikael Zayenz Lagerkvist'; users at gecode.org
> Subject: [gecode-users] High memory consumption during engine declaration
>
> Good morning,
>
> Thank you both for your replies.
>> Another hint: if your model uses the standard Gecode search engines, you
> can
>> inquire how much memory is occupied by the nodes of the search tree. If
>> there is a huge difference between what is reported by the search engine
> and
>> what is reported by your operating system, you program just has a memory
>> leak.
>>
> I indeed use a standard Gecode search engine (Branch-and-Bound). I
> followed you advice and performed the test: both values are coherent.
>> Then, how deep is the search tree? How many variables and propagators does
>> your problem have?
>>
> Here are the figures:
> - Variables: 622
> - Propagators: 25654
> - Deep: 49
>
>> In the end: we could say much more if you provided a little bit more
> detail
>> about what you observe. The information that your program uses a lot of
>> memory is not that helpful in itself.
>>
> Mea culpa: the memory consumption reaches 862MB.
>
> My message was inaccurate yesterday evening: the memory peak occurs when
> the engine constructor is called. It's maybe consistent with the figures
> provided above ?
>
> Benoît
>
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