Version 0.39.0 of pyvista, released three days ago, now features an XdmfReader.
I’ve been using it quite a lot for post-processing time-series data created with fenicsx, so I thought I’d provide a simple example in case anyone else was interested.
import pyvista as pv
from dolfinx import fem, io, mesh
from mpi4py import MPI
comm = MPI.COMM_WORLD
rank = comm.rank
ncells = 100
domain = mesh.create_unit_square(comm, ncells, ncells)
V = fem.FunctionSpace(domain, ("CG", 1))
phi = fem.Function(V)
phi.name = "phi" # This determines the name in reader.set_active_scalars("phi")
# Create xdmf file for saving time series
xdmf = io.XDMFFile(comm, "phi.xdmf", "w")
xdmf.write_mesh(domain)
# Set phi to an arbitrary function at three times and save to xdmf file
t = 0.0
phi.interpolate(lambda x: (t + 0.1) * x[0])
xdmf.write_function(phi, t)
t = 0.5
phi.interpolate(lambda x: (t + 0.1) * x[0])
xdmf.write_function(phi, t)
t = 1.0
phi.interpolate(lambda x: (t + 0.1) * x[0])
xdmf.write_function(phi, t)
xdmf.close()
# Plot with pyvista on one rank - most likely you would put the following in a
# separate script and only run it with one core
if rank == 0:
def plot_sol(func, min, max):
""" Analyse 2d solution over time """
cmap = "plasma"
def load_time(value):
""" Load solution at value specified using the slider """
reader.set_active_time_value(value)
grid = reader.read()[1]
grid.set_active_scalars(func)
p.add_mesh(grid, cmap=cmap, clim=[min, max], scalar_bar_args=sargs)
# Load in data
xdmf_file = "phi.xdmf"
reader = pv.get_reader(xdmf_file)
reader.set_active_time_value(0.0)
grid = reader.read()[1]
grid.set_active_scalars(func)
# Create plot
width = 0.6
sargs = dict(width=width, height=0.1, position_x=(1-width)/2, position_y=0.01)
p = pv.Plotter()
p.add_mesh(grid, cmap=cmap, clim=[min, max], scalar_bar_args=sargs)
p.show_bounds(xtitle="", ytitle="", ztitle="")
p.view_xy()
p.add_slider_widget(load_time, [0.0, 1.0], value=0.0, title="Time",
interaction_event="always", pointa=(0.25, 0.93),
pointb=(0.75, 0.93))
p.show()
plot_sol("phi", 0.0, 1.1)
Some example screenshots:
