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

.. only:: html

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

        Click :ref:`here <sphx_glr_download_matplotlib_plot_parabolic_reflector.py>`
        to download the full example code

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

.. _sphx_glr_matplotlib_plot_parabolic_reflector.py:


parabolic reflector
====================

.. GENERATED FROM PYTHON SOURCE LINES 7-46



.. image-sg:: /matplotlib/images/sphx_glr_plot_parabolic_reflector_001.png
   :alt: plot parabolic reflector
   :srcset: /matplotlib/images/sphx_glr_plot_parabolic_reflector_001.png
   :class: sphx-glr-single-img





.. code-block:: default


    import numpy as np
    import matplotlib.pyplot as plt

    fig, ax = plt.subplots(1,1)


    def y(x):
        return x**2/2

    def df(x,y):
        return np.array([-x, 1])

    #x0 = 1.5
    for x0 in np.linspace(-1.5,1.5,10):
        y0 = 2
        i = np.array([0,-0.2])
        n = df(x0, y(x0))
        pn = -np.dot(i, n)/np.dot(n, n) * n
        o = i + 2*pn
        sample = 2
        line = [np.array([x0]*sample), np.linspace(y(x0),2,sample)]
        if x0 < 0:
            x = np.linspace(x0,0,2)
        else:
            x = np.linspace(0,x0, 2)
        z  = o[1]/o[0]*(x-x0) + y(x0)
        l, = ax.plot(line[0], line[1], '-')
        ax.quiver(x0, y0, i[0], i[1], angles='xy', scale_units='xy', scale=1)
        ax.quiver(x0, y(x0), o[0], o[1], angles='xy', scale_units='xy', scale=1)
        ax.plot(x, z, '-',c=l.get_color())

    x = np.linspace(-2,2,100)
    ax.plot(x, y(x), '-k',lw=3)
    ax.plot(0, 0.5, 'ok')

    ax.set_ylim(0,2)
    ax.set_xlim(-2,2)
    plt.show()


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

   **Total running time of the script:** ( 0 minutes  0.101 seconds)


.. _sphx_glr_download_matplotlib_plot_parabolic_reflector.py:

.. only:: html

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


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

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

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

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


.. only:: html

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

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