While these tutorials are typically meant to be visualized in serial, viskex also runs in parallel. To exemplify this, we will show a parallel case using ipyparallel.
First of all, we start a ipyparallel MPI cluster with 2 processes.
import ipyparallel as ipp
cluster = ipp.Cluster(engines="MPI", profile="mpi", n=2)
cluster.start_and_connect_sync()
Starting 2 engines with <class 'ipyparallel.cluster.launcher.MPIEngineSetLauncher'>
<ipyparallel.client.client.Client at 0x7feab4460380>
The jupyter magic %%px will run the following cells on the ipyparallel cluster.
%%px
import dolfinx.mesh # noqa: E402
import mpi4py.MPI # noqa: E402
%%px
import viskex # noqa: E402
To confirm that we are running in parallel, we can print the rank of the current process and the total number of processes.
%%px
comm_world = mpi4py.MPI.COMM_WORLD
print(f"rank = {comm_world.rank}, size = {comm_world.size}")
[stdout:0] rank = 0, size = 2
[stdout:1] rank = 1, size = 2
Generate a mesh on MPI_COMM_WORLD of the unit square by dividing each edge of the square in 6 segments.
%%px
square_world = dolfinx.mesh.create_unit_square(comm_world, 6, 6)
Plot the mesh defined on MPI_COMM_WORLD. Each rank will plot its local cells, and their neighbors (called ghosts in dolfinx).
%%px
viskex.dolfinx.plot_mesh(square_world)
[output:1]
[output:0]
For comparison, we can generate a similar mesh on MPI_COMM_SELF. Each rank will have its own copy of the whole mesh.
%%px
comm_self = mpi4py.MPI.COMM_SELF
square_self = dolfinx.mesh.create_unit_square(comm_self, 6, 6)
Plot the mesh defined on MPI_COMM_SELF. Each rank will produce a plot which is visually the same, since each rank has its own copy of the same mesh.
%%px
viskex.dolfinx.plot_mesh(square_self)
[output:0]
[output:1]
We finally stop the ipyparallel cluster. Note that when running with Run -> Run all cells all interactive plots will be closed when the kernel executes this cell.
cluster.stop_cluster_sync()
Stopping controller
Controller stopped: {'exit_code': 0, 'pid': 4940, 'identifier': 'ipcontroller-1756699183-5ny4-4922'}
Stopping engine(s): 1756699184
Output for ipengine-1756699183-5ny4-1756699184-4922: 2025-09-01 03:59:44.982 [IPEngine] Loading connection info from $IPP_CONNECTION_INFO 2025-09-01 03:59:44.982 [IPEngine] WARNING | Not using CurveZMQ security 2025-09-01 03:59:45.001 [IPEngine] Loading connection info from $IPP_CONNECTION_INFO 2025-09-01 03:59:45.001 [IPEngine] WARNING | Not using CurveZMQ security 2025-09-01 03:59:45.016 [IPEngine.0] Registering with controller at tcp://127.0.0.1:41161 2025-09-01 03:59:45.016 [IPEngine.1] Registering with controller at tcp://127.0.0.1:41161 2025-09-01 03:59:45.016 [IPEngine.0] Requesting id: 0 2025-09-01 03:59:45.016 [IPEngine.1] Requesting id: 1 2025-09-01 03:59:45.018 [IPEngine.1.1] Shell_addrs: ['tcp://127.0.0.1:58475', 'tcp://127.0.0.1:57741', 'tcp://127.0.0.1:52975'] 2025-09-01 03:59:45.018 [IPEngine.1.1] Connecting shell to tcp://127.0.0.1:58475 2025-09-01 03:59:45.018 [IPEngine.1.1] Connecting shell to tcp://127.0.0.1:57741 2025-09-01 03:59:45.019 [IPEngine.1.1] Connecting shell to tcp://127.0.0.1:52975 2025-09-01 03:59:45.019 [IPEngine.1.1] Starting nanny 2025-09-01 03:59:45.020 [IPEngine.0.0] Shell_addrs: ['tcp://127.0.0.1:58475', 'tcp://127.0.0.1:57741', 'tcp://127.0.0.1:50485'] 2025-09-01 03:59:45.020 [IPEngine.0.0] Connecting shell to tcp://127.0.0.1:58475 2025-09-01 03:59:45.020 [IPEngine.0.0] Connecting shell to tcp://127.0.0.1:57741 2025-09-01 03:59:45.020 [IPEngine.0.0] Connecting shell to tcp://127.0.0.1:50485 2025-09-01 03:59:45.020 [IPEngine.0.0] Starting nanny 2025-09-01 03:59:45.446 [KernelNanny.0] Starting kernel nanny for engine 0, pid=4973, nanny pid=4986 2025-09-01 03:59:45.446 [KernelNanny.0] Nanny watching parent pid 4973. 2025-09-01 03:59:45.453 [KernelNanny.1] Starting kernel nanny for engine 1, pid=4974, nanny pid=4985 2025-09-01 03:59:45.453 [KernelNanny.1] Nanny watching parent pid 4974. 2025-09-01 03:59:45.514 [IPEngine.0.0] Loading IPython extension: storemagic 2025-09-01 03:59:45.514 [IPEngine.0.0] Running code in user namespace: from mpi4py import MPI mpi_rank = MPI.COMM_WORLD.Get_rank() mpi_size = MPI.COMM_WORLD.Get_size() 2025-09-01 03:59:45.516 [IPEngine.0.0] WARNING | debugpy_stream undefined, debugging will not be enabled 2025-09-01 03:59:45.518 [IPEngine.1.1] Loading IPython extension: storemagic 2025-09-01 03:59:45.519 [IPEngine.1.1] Running code in user namespace: from mpi4py import MPI mpi_rank = MPI.COMM_WORLD.Get_rank() mpi_size = MPI.COMM_WORLD.Get_size() 2025-09-01 03:59:45.520 [IPEngine.1.1] WARNING | debugpy_stream undefined, debugging will not be enabled 2025-09-01 03:59:45.523 [IPEngine.0.0] Starting to monitor the heartbeat signal from the hub every 3500 ms. 2025-09-01 03:59:45.523 [IPEngine.0.0] Completed registration with id 0 2025-09-01 03:59:45.526 [IPEngine.1.1] Starting to monitor the heartbeat signal from the hub every 3500 ms. 2025-09-01 03:59:45.526 [IPEngine.1.1] Completed registration with id 1 2025-09-01 03:59:50.263 [IPEngine.0.0] Handling execute_request: 1728ee9c-ee98564274cb44b68b75d313_4922_1 2025-09-01 03:59:50.264 [IPEngine.1.1] Handling execute_request: 1728ee9c-ee98564274cb44b68b75d313_4922_2 2025-09-01 03:59:50.639 [IPEngine.0.0] Handling execute_request: 1728ee9c-ee98564274cb44b68b75d313_4922_3 2025-09-01 03:59:50.639 [IPEngine.1.1] Handling execute_request: 1728ee9c-ee98564274cb44b68b75d313_4922_4 2025-09-01 03:59:51.714 [IPEngine.0.0] Handling execute_request: 1728ee9c-ee98564274cb44b68b75d313_4922_5 2025-09-01 03:59:51.715 [IPEngine.1.1] Handling execute_request: 1728ee9c-ee98564274cb44b68b75d313_4922_6 2025-09-01 03:59:51.725 [IPEngine.0.0] Handling execute_request: 1728ee9c-ee98564274cb44b68b75d313_4922_7 2025-09-01 03:59:51.725 [IPEngine.1.1] Handling execute_request: 1728ee9c-ee98564274cb44b68b75d313_4922_8 2025-09-01 03:59:51.739 [IPEngine.0.0] Handling execute_request: 1728ee9c-ee98564274cb44b68b75d313_4922_9 2025-09-01 03:59:51.739 [IPEngine.1.1] Handling execute_request: 1728ee9c-ee98564274cb44b68b75d313_4922_10 2025-09-01 03:59:52.097 [IPEngine.0.0] Handling execute_request: 1728ee9c-ee98564274cb44b68b75d313_4922_11 2025-09-01 03:59:52.098 [IPEngine.1.1] Handling execute_request: 1728ee9c-ee98564274cb44b68b75d313_4922_12 2025-09-01 03:59:52.108 [IPEngine.0.0] Handling execute_request: 1728ee9c-ee98564274cb44b68b75d313_4922_13 2025-09-01 03:59:52.108 [IPEngine.1.1] Handling execute_request: 1728ee9c-ee98564274cb44b68b75d313_4922_14 2025-09-01 03:59:53.052 [KernelNanny.0] Pipe closed, parent 4973 has status: zombie 2025-09-01 03:59:53.052 [KernelNanny.0] Notifying Hub that our parent has shut down 2025-09-01 03:59:53.072 [KernelNanny.1] Pipe closed, parent 4974 has status: zombie 2025-09-01 03:59:53.072 [KernelNanny.1] Notifying Hub that our parent has shut down 2025-09-01 03:59:53.089 [KernelNanny.0] Parent 4973 exited with status None. 2025-09-01 03:59:53.095 [KernelNanny.1] Parent 4974 exited with status None.
engine set stopped 1756699184: {'exit_code': 1, 'pid': 4968, 'identifier': 'ipengine-1756699183-5ny4-1756699184-4922'}