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

.. only:: html

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

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

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

.. _sphx_glr__gallery_vectors_vectors_swirl.py:


Swirling vectors
================

Example showing swirling vectors. Similar to matplotlib quiver.

.. GENERATED FROM PYTHON SOURCE LINES 8-47



.. image-sg:: /_gallery/vectors/images/sphx_glr_vectors_swirl_001.webp
   :alt: vectors swirl
   :srcset: /_gallery/vectors/images/sphx_glr_vectors_swirl_001.webp
   :class: sphx-glr-single-img


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

 .. code-block:: none

    /opt/hostedtoolcache/Python/3.12.12/x64/lib/python3.12/site-packages/pygfx/objects/_ruler.py:400: RuntimeWarning: divide by zero encountered in divide
      screen_full = (ndc_full[:, :2] / ndc_full[:, 3:4]) * half_canvas_size
    /opt/hostedtoolcache/Python/3.12.12/x64/lib/python3.12/site-packages/pygfx/objects/_ruler.py:400: RuntimeWarning: invalid value encountered in divide
      screen_full = (ndc_full[:, :2] / ndc_full[:, 3:4]) * half_canvas_size
    /opt/hostedtoolcache/Python/3.12.12/x64/lib/python3.12/site-packages/pygfx/objects/_ruler.py:412: RuntimeWarning: invalid value encountered in divide
      screen_sel = (ndc_sel[:, :2] / ndc_sel[:, 3:4]) * half_canvas_size







|

.. code-block:: Python


    # test_example = true

    import numpy as np
    import fastplotlib as fpl

    figure = fpl.Figure(cameras="3d", controller_types="orbit", size=(700, 700))

    start, stop, step = -1, 1, 0.3

    # Make the grid
    x, y, z = np.meshgrid(
        np.arange(start, stop, step),
        np.arange(start, stop, step),
        np.arange(start, stop, step),
    )

    # Make the direction data for the arrows
    u = np.sin(np.pi * x) * np.cos(np.pi * y) * np.cos(np.pi * z)
    v = -np.cos(np.pi * x) * np.sin(np.pi * y) * np.cos(np.pi * z)
    w = np.sqrt(2.0 / 3.0) * np.cos(np.pi * x) * np.cos(np.pi * y) * np.sin(np.pi * z)

    positions = np.column_stack([x.ravel(), y.ravel(), z.ravel()])
    directions = np.column_stack([u.ravel(), v.ravel(), w.ravel()])


    vectors = figure[0, 0].add_vectors(
        positions=positions,
        directions=directions,
    )

    figure.show()


    # NOTE: fpl.loop.run() should not be used for interactive sessions
    # See the "JupyterLab and IPython" section in the user guide
    if __name__ == "__main__":
        print(__doc__)
        fpl.loop.run()


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

   **Total running time of the script:** (0 minutes 0.413 seconds)


.. _sphx_glr_download__gallery_vectors_vectors_swirl.py:

.. only:: html

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

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

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

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

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


.. only:: html

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

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