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# 2018 © Bruno Chareyre <bruno.chareyre@grenoble-inp.fr>
# Really a helloWorld (or almost, I couldn't refrain from adding a bit more).
# Check other examples for concrete usage of mpy in DEM simulations
from yade import mpy as mp
mp.initialize(3)
#mp.VERBOSE_OUTPUT = True # to see more of what happens behind the scene
mp.mprint("I'm here")
if mp.rank == 0:
# say hello:
mp.sendCommand(executors=[1, 2], command="mprint('Yes I am really here')", wait=False)
# get retrun values if wait=True (blocking comm., think twice)
print(mp.sendCommand(executors="all", command="len(O.bodies)", wait=True))
## exploit sendCommand to send data between yade instances directly with mpi4py (see mpi4py documentation)
## in the message we actually tell the worker to wait another message (nested comm), but the second one
## uses underlying mpi4py, and it handles pickable objects
mp.sendCommand(executors=1, command="message=comm.recv(source=0); mprint('received: ',message)", wait=False)
mp.comm.send("hello", dest=1)
## pickable objects
## pay attention to pointer adresses, they are different! (as expected)
## this is moving data around between independent parts of memory
mp.sendCommand(
executors=1,
command="O.bodies.append(Body()); O.bodies[0].shape=Sphere(radius=0.456); comm.send(O.bodies[0],dest=0); mprint('sent a ',O.bodies[0].shape)",
wait=False
)
bodyFrom1 = mp.comm.recv(source=1)
mp.mprint("received a ", bodyFrom1.shape, "with radius=", bodyFrom1.shape.radius)
# More bodies
# note that 'rank' is used instead of mp.rank, the scope of the mpy module is accessed here
mp.sendCommand(executors=[1, 2], command="ids=O.bodies.append([sphere((xx,1.5+rank,0),0.5) for xx in range(-1,2)])", wait=True)
wallId = O.bodies.append(box(center=(0, 0, 0), extents=(2, 0, 1), fixed=True)) #master only
print(mp.sendCommand(executors="all", command="len(O.bodies)", wait=True))
mp.sendCommand(executors=[1, 2], command="list(map(lambda b: setattr(b,'subdomain',rank),O.bodies))", wait=True)
print("Assigned bodies:", mp.sendCommand([1, 2], "len([b for b in O.bodies if b.subdomain==rank])", True))
# Kill workers pool, then start again with a new
# any data in the old threads is lost
mp.disconnect()
mp.initialize(8)
# not all workers will be displayed because mp.MAX_RANK_OUTPUT=5 by default
mp.sendCommand(executors="slaves", command="mprint('I am a new one')", wait=True)
# no need to diconnect here, it will be called when exiting yade anyway
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