[cjc96]

Hey everyone,

I'm continue to work on my custom Lagrangian-Eulerian solver and am at the point where I am focusing more on efficiency than functionality.

I'm currently recording information associated with particles that cross a pre-defined plane in space using the following loop at the end of the evolve function:

    forAllIter(typename KinematicCloud<CloudType>, *this, iter)
    {
        parcelType& p = iter();

        if (p.position().x()>cloud.solution().extractionPlane())
        {
            this->extractionData(p);
        }
    }

With extractionPlane and extractionData being my own custom cloud property and function respectively.

I'm fairly confident that this loops over every particle in the domain, whereas in this case, I only need to test active particles, (those that are have not impinged on a surface). Towards the end of my simulation I have over 2,000,000 inactive particles so this should provide considerable savings.

Now, it's easy to identify inactive particles, as p.active() is simply equal to zero, and I'm wondering whether change the loop to only pass over those particles with the active flag?

Thanks as per usual!

[olesen]

Beyond simply adding a test for p.active() into your if condition can't see how to make this any faster, unless the particles happened to already be presorted into active/inactive as some other part of your process.

[cjc96]

Originally Posted by olesen

Beyond simply adding a test for p.active() into your if condition can't see how to make this any faster, unless the particles happened to already be presorted into active/inactive as some other part of your process.

Hey Mark,

Thanks for your input!

So, beyond doing something like an initial loop over all the particles to identify the active ones (which would of course make things even slower) there is no way to loop over only the active particles?

[olesen]

If you check out src/lagrangian/basic/cloud you will see that it is implemented as a linked list, so not much to optimize there.
And having an iterator for active-only particles (doesn't exist) would add some syntax sugar but not add performance.