Hi guys
After a carefull inspection of valgrind outputs, I came to the
conclusion that
(1) this line :
for(InteractionContainer::iterator I=interactions->begin();
I!=interactions->end(); ++I)
is not optimized with my compiler. It means that interactions->end()
will be executed at each iteration, and it needs a lot of time in loops.
(2) Even worse, in this code from PhysicalActionVectorVector.cpp :
shared_ptr<PhysicalAction>& PhysicalActionVectorVector::find(unsigned
int id , int actionIndex )
{
if( physicalActions.size() <= id ) // this is very rarely executed,
only at beginning.
// somebody is accesing out of bounds, make sure he will find, what
he needs - a resetted PhysicalAction of his type
{ ....
the size of physicalActions WILL BE COMPUTED each time somebody type
physicalActions.find(i,j) !!! As a result, size() is executed around
4500 times per timestep in a TriaxialTest with 400 spheres, which
represents around 20% of the cost of a function like
ElasticContactLaw.action().
(3) actionStiffness->getClassIndex() is always executed too. It is
better to add a member data stiffnessIndex to the engine, then define it
only once as stiffnessIndex=actionStiffness->getClassIndex() in the
constructor, and finally use stiffnessIndex for internal tests instead
of getClassIndex().
I'm a bit surprised because I thought the compiler would fix all that
alone. It looks like it doesn't. I don't know if this is because of
debug symbols or something else limiting optimization (what is the
optimization level whith scons flag "optimization=True", is it
equivalent to -O3?).
Afer fixing things here and there concerning those 3 points above (e.g.
I added a member data called "size" to the container to avoid computing
it all the time), I could run the triaxial test around 25% faster.
I can commit those changes soon, I'm curious to know the results on
other computers.
Bruno
--
_______________
Chareyre Bruno
Maitre de conference
Institut National Polytechnique de Grenoble
Laboratoire 3S (Soils Solids Structures) - bureau E145
BP 53 - 38041, Grenoble cedex 9 - France
Tél : 33 4 56 52 86 21
Fax : 33 4 76 82 70 43
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