Relationship between ParticleTile::resize() and particles.tile_size ?

[n8xm]

What is the relationship between the resize() method of ParticleTile and the input parameter particles.tile_size ?

• I looked at the implementation of ParticleTile::resize() in AMReX_ParticleTile.h, and it appears to resize the AoS and SoA data structures associated with the ParticleTile. From my earlier discussion with @atmyers, it sounds like particles.tile_size controls the number of ParticleTile objects per grid, when do_tiling is set to 1.

• In addition, from what I can tell, particles.tile_size refers to a size in terms of number of grid cells, whereas ParticleTile::resize() changes the number of particles that the ParticleTile object owns.

Am I correct, or am I missing something?

[atmyers]

Hi Nathan,

You are correct. particles.tile_size is in terms of number of grid cells and controls the number of ParticleTiles per grid. ParticleTile::resize() adjusts the lengths of the AoS and SoA data structures on a given ParticleTile in terms of the number of particles. A common use for ParticleTile::resize() would be to allocate space for some number of particles on a tile, then fill in the data for each particle.