[yt-users] Mapping of particle field to the grid

[Yi-Hao Chen]

Dear yt-users,

I am working on FLASH datasets with particles. I have some self-defined
fields (specifically Lorentz factors) that are stored in the particle data
and would like to map them onto the mesh grid. I've been trying the
"add_deposited_particle_field" that is in the dev version. Currently I use
the "cic" method, in which a particle will populate the nearby 8 cells (in
3D). However, since my particles are sparser than the mesh cells, many of
the cells do not have particles nearby and thus are empty.

I would like to find a way to interpolate for those empty cells, i.e. to
smooth the particle field. Are there any suggestions or directions I should
look into?


It would also be very helpful if I can get the list of N nearest neighbor
particles for each cell. I've looked into the nearest neighbor function
http://yt-project.org/docs/dev/analyzing/fields.html#computing-the-nth-nearest-neighbor

But it seems that it is implemented only for octree-based data objects (and
can only perform in a particle-to-particle fashion?), while FLASH data are
loaded into yt as "patch-based" data object.
http://yt-project.org/doc/developing/creating_frontend.html#data-localization-structures

Is there any function that can get the nearest particle neighbors of each
cell?

Thank you,
Yi-Hao

--
Yi-Hao Chen
Graduate Student
Department of Astronomy
University of Wisconsin-Madison
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