Data Distribution: N-D or Patches

[ax3l]

Right now we can distribute data along a 1D axis, but coupling to live simulations might need to "imitate" the spatial distribution of the RAM #4 accordingly.

We should therefore be able to distribute the data at least along a grid, more flexible would be to distribute it over patches immediately. Each patch can than consist of a rectangular area with a distinct offset and size. Neighbors around it's extend could be stored as a list (if necessary).

[heikoburau]

What is the difference between distributing along a grid and over patches?

[ax3l]

patches do not to be regularly arranged in contrary to ranks in a grid. (grid means: the arrangement of the MPI ranks in that case, as in MPI_Cart_create)

left: static load balancing on a grid as in PIConGPU with --grid-dist, right: arbitrary but rectangular patches a MPI rank is responsible for:

[heikoburau]

very nice! How did you made this picture? :)

[ax3l]

Thanks! Kudos to sketch.io and gimp :)

[bussmann]

Beautiful!

[ax3l]

thanks, but it took me only 2min to draw that.
that pull requ. description is beautiful, I am just a lousy amateur ;)

[heikoburau]

n-dimensional distributing along a grid is now supported.

[bussmann]

Great job!

[ax3l]

@Heikman awesome, did/can you add some examples how to do so in the docs?

[heikoburau]

yes, they were added by the 1.2 release last year.