yade-dev team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx>]

> although, I do not think, that the vector increasing with NULL-vectors
> will lead to a memory leakage,
Even a pointer pointing to nowhere needs memory for the pointer itself.
vector<ptr>(1000,NULL) is taking more memory than vector<ptr>(10,NULL),
or it would be a big surprise for me.
Actually it doesn't matter if the pointers are null or not, overall the
memory that these vectors need is sizeof(ptr)*vector.size().
Hence the memory leak.
Plus many other vectors resized based on scene.bodies.size() and
supposed to contain other things (bigger than a pointer in most cases),
there are many occurences of this.
Of course it would be even worst if the pointers were actually pointing
to true bodies, them to would waste memory.

> We can return back the previous behavior, but I would want to have
> unique body ids. So, we need  to uncouple b.id <http://b.id> and
> position as you
> suggested.
>
> I have a god feeling that it can bring us additional bugs, in cases, where
> body id is associated to its position. Not sure, how many of them are in
> the code.
Avoiding bugs is why I suggested to use "label" for post-processing and
"id" for index in bodies, not the other way.
Body label will be unique, body id will not. If we do that we don't
uncouple id and position.
The recorders will have to be modified, so that they record labels
instead of ids.
The rest of the code will be back to the previous state. No bad bugs to
be expected.

Cheers

Bruno





>
> Thanks
>
>
> Anton
>
> 2014-09-15 13:14 GMT+02:00 Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx
> <mailto:bruno.chareyre@xxxxxxxxxxx>>:
>
>
>     > Do you observe some problems with this commit?
>     Mostly a memory leak, since the size of the vector is increasing
>     forever, and many other vectors alike.
>     For instance:
>     https://github.com/yade/trunk/blob/5776b8923372d9e7563dee0756d4224f01a954a8/pkg/common/InsertionSortCollider.cpp#L234
>
>     Also maybe bad performances in parallel sections, the collider
>     especially but not only, if the first 99% of scene.bodies are occupied
>     by null pointers.
>     Also some algorithms in Yade may assume that max id is the number of
>     bodies, but I have no precise examples of that. The problems will
>     remain
>     hiden until someone use such algorithm in a simulation where
>     bodies are
>     erased/created.
>
>     A solution would be to uncouple b.id <http://b.id> (the position
>     in scene.bodies) and
>     b.label (the identifier in post-processing functions).
>
>     Cheers.
>
>     Bruno
>
>
>     2014-09-15 11:20 GMT+02:00 Bruno Chareyre
>     <bruno.chareyre@xxxxxxxxxxx <mailto:bruno.chareyre@xxxxxxxxxxx>>:
>     >> Hi Anton,
>     >> I'm a bit late on that one but... does it mean that the size ob
>     O.bodies is
>     >> increasing forever when bodies are deleted and added?
>     >> Bruno
>     >>
>     >>
>     >> On 17/07/14 10:14, noreply@xxxxxxxxxxxxx
>     <mailto:noreply@xxxxxxxxxxxxx> wrote:
>     >>
>     >> ------------------------------------------------------------
>     >> revno: 4086
>     >> committer: Anton Gladky <gladky.anton@xxxxxxxxx
>     <mailto:gladky.anton@xxxxxxxxx>>
>     >> timestamp: Thu 2014-07-17 08:34:00 +0200
>     >> message:
>     >>   Disable reusing of removed body ids.
>     >>
>     >>   Some change in BodyContainer. Previously the ids of removed
>     >>   bodies could be reused by newly created particles. It caused
>     >>   some problems, for instance, by saving in VTK file and building
>     >>   pathlines of them in ParaView.
>     >>
>     >>   Also it could lead to some unexpected behaviour during intensive
>     >>   removal/adding particles.
>     >> modified:
>     >>   core/BodyContainer.cpp
>     >>   core/BodyContainer.hpp
>     >>
>     >>
>     >> --
>     >> lp:yade
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>     >> _______________
>     >> Bruno Chareyre
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>     --
>     _______________
>     Bruno Chareyre
>     Associate Professor
>     ENSE³ - Grenoble INP
>     Lab. 3SR
>     BP 53
>     38041 Grenoble cedex 9
>     Tél : +33 4 56 52 86 21
>     Fax : +33 4 76 82 70 43
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-- 
_______________
Bruno Chareyre
Associate Professor
ENSE³ - Grenoble INP
Lab. 3SR
BP 53
38041 Grenoble cedex 9
Tél : +33 4 56 52 86 21
Fax : +33 4 76 82 70 43
________________