"""
.. _read_parallel_example:

Parallel Files
~~~~~~~~~~~~~~

The VTK library supports parallel file formats. Reading meshes broken up into
several files is natively supported by VTK and PyVista.
"""
import os

# sphinx_gallery_thumbnail_number = 1
import pyvista as pv
from pyvista import examples

###############################################################################
# Let's go ahead and download the sample dataset containing an
# :class:`pyvista.UnstructuredGrid` broken up into several files.
#
# Let's inspect where this downloaded our dataset by setting ``load=False`` and
# looking at the directory containing the file we downloaded.
filename = examples.download_blood_vessels(load=False)
path = os.path.dirname(filename)
os.listdir(path)


###############################################################################
os.listdir(os.path.join(path, "T0000000500"))


###############################################################################
# Note that a ``.pvtu`` file is available alongside a directory. This
# directory contains all the parallel files or pieces that make the whole mesh.
# We can simply read the ``.pvtu`` file and VTK will handle putting the mesh
# together.
mesh = pv.read(filename)
mesh


###############################################################################
# Plot the pieced together mesh
mesh.plot(scalars="node_value", categories=True)


###############################################################################
mesh.plot(scalars="density")