Hi, Can you please write an example of accessing memory pool handles, iterating them and converting the handles to particle properties? Thanks in advance. Best regards, Shahab
On Monday, October 19, 2020 at 10:57:26 PM UTC-4 Wolfgang Bangerth wrote: > On 10/19/20 9:03 AM, blais...@gmail.com wrote: > > I am not sur if I fully understand the memory structure of the Property > Pool > > (or at least I am still confused by it). > > If I understand correctly, the properties of all the particles are > stored in a > > single Handle array and the get_properties of a single particle returns > an > > array view pointing to this large array. > > However, the n_properties_per_slot() returns the number of properties > > associated with a single particle. Is there a way to know from within > the > > property pool the size of the handle array? > > Maybe > https://github.com/dealii/dealii/pull/11057 > clarifies the intent of the PropertyPool? The idea is that the property > pool > is responsible for all of the memory allocated for particle properties. > > I've come to realize that what you want to do wasn't possible in the > current > design (because we don't keep track of which memory we have allocated), so > wrote > https://github.com/dealii/dealii/pull/11059 > > Once that is merged, I think what you want to do is maybe something along > the > lines of the following addition to the PropertyPool class: > > /** > * Return the first of all of the memory pool handles that are managed > * by this class. Iterating from begin() to end() then returns the handles > * associated with all particles in the ParticleHandler class that owns > * this property pool; using the get_properties() function, these handles > * can be converted to ArrayView objects that then allow access to the > * actual properties. > * > * This function can be used to access and modify the properties of all > * particles, though possibly in a different order than if one accessed > * them using ParticleHandler::begin() and ParticleHandler::end(). > * > * @note PropertyPools also store the properties of ghost particles, > * and consequently iterating over all handles also reaches the > * properties of ghost particles. > */ > std::set<Handle>::iterator begin () > { return currently_open_handler.begin() } > > + same for the corresponding end() function. > > > > If the properties are stored in a continuous block, one could easily > write a > > function that takes into argument a vector of property index, the value > to set > > and the number of particles for example. This function would then be > called > > from the particle handler which in turn would have an interface to this > > function with the vector of property index and the value to set. > > Would that be the right approach? If so, I can work on a PR. > > PropertyPool doesn't advertise how it stores properties. Currently, it's > not > in one large block, though that's something we might want to change at > some > future point. The interface above avoids exposing how exactly they are > stored. > > Best > W. > > > -- > ------------------------------------------------------------------------ > Wolfgang Bangerth email: bang...@colostate.edu > www: http://www.math.colostate.edu/~bangerth/ > > -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to dealii+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/0ef442aa-6197-47c6-b7ca-b40c04e340edn%40googlegroups.com.
