.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "auto_how_to/example_blockmesh.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        :ref:`Go to the end <sphx_glr_download_auto_how_to_example_blockmesh.py>`
        to download the full example code.

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_auto_how_to_example_blockmesh.py:


Run blockMesh and checkMesh from Python
=======================================

Build a mesh from ``system/blockMeshDict`` with
:func:`pybFoam.meshing.generate_blockmesh` and inspect it with
:func:`pybFoam.meshing.checkMesh`. Both are direct bindings of the
OpenFOAM utilities — the returned ``fvMesh`` is a regular mesh that can
be used immediately for field access, sampling, or further checks.

Prerequisite: OpenFOAM v2312+ sourced; pybFoam installed.

.. GENERATED FROM PYTHON SOURCE LINES 15-19

Prepare a working case
----------------------
:func:`pybFoam.clone_example` copies the named example into a tmp
directory so the baseline under ``examples/`` stays pristine.

.. GENERATED FROM PYTHON SOURCE LINES 19-26

.. code-block:: Python


    from pybFoam import Time, argList, clone_example, dictionary
    from pybFoam.meshing import checkMesh, generate_blockmesh

    case = clone_example("case")
    print(f"working case: {case}")





.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    working case: /tmp/pybfoam_q4adtry1/case




.. GENERATED FROM PYTHON SOURCE LINES 27-29

Generate the mesh
-----------------

.. GENERATED FROM PYTHON SOURCE LINES 29-37

.. code-block:: Python


    time = Time(argList([str(case), "-case", str(case)]))
    mesh = generate_blockmesh(time, dictionary.read(str(case / "system" / "blockMeshDict")))

    print(f"nCells  = {mesh.nCells()}")
    print(f"nFaces  = {mesh.nFaces()}")
    print(f"nPoints = {mesh.nPoints()}")





.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    nCells  = 2268
    nFaces  = 9176
    nPoints = 4746




.. GENERATED FROM PYTHON SOURCE LINES 38-44

Inspect mesh quality
--------------------
``checkMesh`` returns a structured dict with ``mesh_stats``,
``cell_types``, ``topology``, ``geometry``, ``quality``, ``passed``,
``failed``, and ``total_errors``. Select the flags you want — here we
run the topology + geometry checks.

.. GENERATED FROM PYTHON SOURCE LINES 44-58

.. code-block:: Python


    result = checkMesh(
        mesh,
        check_topology=True,
        all_topology=True,
        all_geometry=True,
        check_quality=False,
    )

    print(f"passed       = {result['passed']}")
    print(f"total_errors = {result['total_errors']}")
    print(f"hex cells    = {result['cell_types'].get('hexahedra', 0)}")
    print(f"max non-orth = {result['geometry']['max_non_orthogonality']:.3f}")





.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    passed       = True
    total_errors = 0
    hex cells    = 2268
    max non-orth = 0.000




.. GENERATED FROM PYTHON SOURCE LINES 59-64

Patch breakdown
---------------
Iterate ``mesh.boundary()`` (the ``fvBoundaryMesh``) to see what
patches the mesh actually has — useful when verifying that the
boundary section of ``blockMeshDict`` came through as expected.

.. GENERATED FROM PYTHON SOURCE LINES 64-74

.. code-block:: Python


    boundary = mesh.boundary()
    patches = []
    for i in range(len(boundary)):
        patch = boundary[i]
        name = str(patch.name())
        size = patch.size()
        patches.append((name, size))
        print(f"{name:<16s} faces={size}")





.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    leftWall         faces=50
    rightWall        faces=50
    lowerWall        faces=62
    atmosphere       faces=46
    defaultFaces     faces=0




.. GENERATED FROM PYTHON SOURCE LINES 75-79

Plot the patch face counts
--------------------------
A simple matplotlib bar chart confirms the mesh has the patches the
user expects. A missing or zero-face patch shows up immediately.

.. GENERATED FROM PYTHON SOURCE LINES 79-94

.. code-block:: Python


    import matplotlib.pyplot as plt

    names = [p[0] for p in patches]
    sizes = [p[1] for p in patches]

    fig, ax = plt.subplots(figsize=(6, 3))
    ax.bar(names, sizes, color="steelblue")
    ax.set_ylabel("number of faces")
    ax.set_title(f"Boundary patches ({mesh.nCells()} internal cells)")
    for i, n in enumerate(sizes):
        ax.text(i, n, f"{n}", ha="center", va="bottom", fontsize=9)
    fig.tight_layout()
    plt.show()




.. image-sg:: /auto_how_to/images/sphx_glr_example_blockmesh_001.png
   :alt: Boundary patches (2268 internal cells)
   :srcset: /auto_how_to/images/sphx_glr_example_blockmesh_001.png
   :class: sphx-glr-single-img





.. GENERATED FROM PYTHON SOURCE LINES 95-100

See also
--------

- :doc:`example_read_dictionaries` — extract typed field entries from
  any dictionary, including ``blockMeshDict``.


.. rst-class:: sphx-glr-timing

   **Total running time of the script:** (0 minutes 0.148 seconds)


.. _sphx_glr_download_auto_how_to_example_blockmesh.py:

.. only:: html

  .. container:: sphx-glr-footer sphx-glr-footer-example

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: example_blockmesh.ipynb <example_blockmesh.ipynb>`

    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: example_blockmesh.py <example_blockmesh.py>`

    .. container:: sphx-glr-download sphx-glr-download-zip

      :download:`Download zipped: example_blockmesh.zip <example_blockmesh.zip>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_