Quickstart

First, ensure that mpiparticles is installed.

One rank

A ParticleStore keeps the markers of one rank in component-major arrays: positions (ndim, n), velocities (nvel, n), weights, alive flags and int64 ids.

import cunumpy as xp

from mpiparticles import ParticleStore

store = ParticleStore(ndim=2, nvel=3)
ids = store.add(xp.asarray([[0.1, 0.9], [0.2, 0.8]]), xp.zeros((3, 2)), weights=1.0)

store.deactivate(xp.asarray([False, True]))  # dead markers stay until compacted
store.compact_if_needed()
print(store.num_alive, store.length)

Several ranks

Split a box between the ranks with a Decomposition, push the markers, and call migrate after every push. It is collective: every rank calls it, also a rank with nothing to send.

import maybempi

from mpiparticles import BoxDecomposition, IdAllocator, ParticleStore, migrate

comm = maybempi.get_mpi().COMM_WORLD
decomposition = BoxDecomposition(comm, [0.0, 0.0], [1.0, 1.0], proc_sizes=[2, 2])
store = ParticleStore(2, 3, id_allocator=IdAllocator.from_comm(comm))

# ... add the markers of this rank, push them ...
sent, received = migrate(store, decomposition)

mpiexec -n 4 python example.py   # or just: python example.py (one rank)

The tutorial runs this on four ranks and checks that no marker or id is lost. See the API reference for every function.