Saving particles for checkpointing

[blais...@gmail.com]

Dear all, I hope you are well.

I am trying to add checkpointing in our particle code. Particles do not have a save function, but they have a serialize function, which I think would be exactly what I need.

However, the function is not documented. It takes as an argument something of class Archive, which I could not find any information on.

I also grepped all over the tests, but I could not find a usage of this function.

https://www.dealii.org/current/doxygen/deal.II/classParticles_1_1ParticleHandler.html#a877e1aac8ef0ad6fa85ed400bf71eb1c

Would anybody have a quick tutorial or example on how this function could be used for checkpoint the particle_handler and the properties of the particles?

Thank you so much :)!

Bruno

[peterrum]

Do the following links help?

- https://github.com/dealii/dealii/blob/master/tests/serialization/particle_handler_01.cc

- https://github.com/dealii/dealii/blob/master/tests/serialization/particle_handler_02.cc

Peter

[blais...@gmail.com]

I think they will! I feel kind-off dumb not having realized that :)

Thanks!

Bruno

[blais...@gmail.com]

I have one tiny question actually.

In all tests, the std::ostringstream oss which contains some information about the number of particles and the data being serialized is kept.

Generally, I guess this should be written to an auxiliary file, then re-read before deserialization can occur?

[Wolfgang Bangerth]

On 12/9/20 5:32 PM, blais...@gmail.com wrote:
> I have one tiny question actually.
> In all tests, the std::ostringstream oss which contains some information about
> the number of particles and the data being serialized is kept.
> Generally, I guess this should be written to an auxiliary file, then re-read
> before deserialization can occur?

Yes, precisely. In fact, instead of a std::ostringstring, when you write to
file you might as well have directly given a std::ofstream.

That that data could be written to a file is not important for the test,
though, and so it doesn't do that.

Best
W.


--
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Wolfgang Bangerth email: bang...@colostate.edu
www: http://www.math.colostate.edu/~bangerth/

[blais...@gmail.com]

Awesome.

It works perfectly

Thank you all :)!

[rene.gas...@mailbox.org]

Hi Bruno,

The particles do indeed have a serialize function, but it is somewhat tricky to use directly and not really necessary (you can see an example here: https://github.com/dealii/dealii/pull/11314/files#diff-fbe7d72b2e0af27fba150e987a3ce0c2cad90b6054decc94810c898fef6d9eaf). The more common case is that you have the particles inside a ParticleHandler that is connected to a triangulation. For this case the ParticleHandler can take care of the serialization by attaching the particle data to the triangulation data that is serialized anyway. An example is inside the test serialization/particle_handler_01 and _02.

Hope that helps, let me know in case you run into problems (e.g. if you want to serialize particles and a FE solution vector the order of serialization/deserialization is critical and a bit confusing due to the triangulation signals),

Best,

Rene