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

.. only:: html

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

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

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

.. _sphx_glr_auto_graphs_plot_graphs_basics.py:


A quick start guide to graphs
==============================

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.. code-block:: Python


    # sphinx_gallery_thumbnail_number = 4







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In this example, we show how to create graphs. We show how to create and configure its axes and its colors. We show how to create a plot based on the combination of several plots.

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The `draw` method the `Graph` class
-----------------------------------

The simplest way to create a graph is to use the `draw` method. The :class:`~openturns.Normal` distribution for example provides a method to draw its density function.

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.. code-block:: Python

    import openturns as ot
    import openturns.viewer as viewer
    import matplotlib.pyplot as plt

    ot.Log.Show(ot.Log.NONE)








.. GENERATED FROM PYTHON SOURCE LINES 25-28

.. code-block:: Python

    n = ot.Normal()
    n






.. raw:: html

    <div class="output_subarea output_html rendered_html output_result">
    Normal
    <ul>
      <li>name=Normal</li>
      <li>dimension=1</li>
      <li>weight=1</li>
      <li>range=]-inf (-7.65063), (7.65063) +inf[</li>
      <li>description=[X0]</li>
      <li>isParallel=true</li>
      <li>isCopula=false</li>
    </ul>

    </div>
    <br />
    <br />

.. GENERATED FROM PYTHON SOURCE LINES 29-32

.. code-block:: Python

    graph = n.drawPDF()
    view = viewer.View(graph)




.. image-sg:: /auto_graphs/images/sphx_glr_plot_graphs_basics_001.png
   :alt: plot graphs basics
   :srcset: /auto_graphs/images/sphx_glr_plot_graphs_basics_001.png
   :class: sphx-glr-single-img





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To configure the look of the plot, we can first observe the type of graph returned by the `drawPDF` method returns: it is a :class:`~openturns.Graph`.

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.. code-block:: Python

    graph = n.drawPDF()
    type(graph)








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The class:`~openturns.Graph` class provides several methods to configure the legends, the title and the colors.
Since a graph  can contain several sub-graphs, the `setColors` method takes a list of colors as inputs argument: each item of the list corresponds to the sub-graphs.

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.. code-block:: Python

    graph.setXTitle("N")
    graph.setYTitle("PDF")
    graph.setTitle("Probability density function of the standard Gaussian distribution")
    graph.setLegends(["N"])
    graph.setColors(["blue"])
    view = viewer.View(graph)




.. image-sg:: /auto_graphs/images/sphx_glr_plot_graphs_basics_002.png
   :alt: Probability density function of the standard Gaussian distribution
   :srcset: /auto_graphs/images/sphx_glr_plot_graphs_basics_002.png
   :class: sphx-glr-single-img





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Combine several graphs
----------------------

In order to combine several graphs, we can use the `add` method.

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Let us create an empirical histogram from a sample.

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.. code-block:: Python

    sample = n.getSample(100)








.. GENERATED FROM PYTHON SOURCE LINES 64-67

.. code-block:: Python

    histo = ot.HistogramFactory().build(sample).drawPDF()
    view = viewer.View(histo)




.. image-sg:: /auto_graphs/images/sphx_glr_plot_graphs_basics_003.png
   :alt: X0 PDF
   :srcset: /auto_graphs/images/sphx_glr_plot_graphs_basics_003.png
   :class: sphx-glr-single-img





.. GENERATED FROM PYTHON SOURCE LINES 68-69

Then we add the histogram to the `graph` with the `add` method. The `graph` then contains two plots.

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.. code-block:: Python

    graph.add(histo)
    view = viewer.View(graph)




.. image-sg:: /auto_graphs/images/sphx_glr_plot_graphs_basics_004.png
   :alt: Probability density function of the standard Gaussian distribution
   :srcset: /auto_graphs/images/sphx_glr_plot_graphs_basics_004.png
   :class: sphx-glr-single-img





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Draw a cloud
------------

The :class:`~openturns.Cloud` class creates clouds of bidimensional points. To illustrate it, let us create two Normal distributions in two dimensions.

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Create a Funky distribution

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.. code-block:: Python

    corr = ot.CorrelationMatrix(2)
    corr[0, 1] = 0.2
    copula = ot.NormalCopula(corr)
    x1 = ot.Normal(-1.0, 1)
    x2 = ot.Normal(2, 1)
    x_funk = ot.JointDistribution([x1, x2], copula)








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Create a Punk distribution

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.. code-block:: Python

    x1 = ot.Normal(1.0, 1)
    x2 = ot.Normal(-2, 1)
    x_punk = ot.JointDistribution([x1, x2], copula)








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Let us mix these two distributions.

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.. code-block:: Python

    mixture = ot.Mixture([x_funk, x_punk], [0.5, 1.0])








.. GENERATED FROM PYTHON SOURCE LINES 102-105

.. code-block:: Python

    n = 500
    sample = mixture.getSample(n)








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.. code-block:: Python

    graph = ot.Graph("n=%d" % (n), "X1", "X2", True, "")
    cloud = ot.Cloud(sample)
    graph.add(cloud)
    view = viewer.View(graph)




.. image-sg:: /auto_graphs/images/sphx_glr_plot_graphs_basics_005.png
   :alt: n=500
   :srcset: /auto_graphs/images/sphx_glr_plot_graphs_basics_005.png
   :class: sphx-glr-single-img





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We sometimes want to customize the graph by choosing the type of point (square, triangle, circle, etc.), of line (continuous, dashed, etc.) or another parameter.
We can know the list of possible values with the corresponding `getValid` method.

For example, the following function returns the possible values of the `PointStyle` parameter.

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.. code-block:: Python

    ot.Drawable.GetValidPointStyles()






.. raw:: html

    <div class="output_subarea output_html rendered_html output_result">
    [square,circle,triangleup,plus,times,diamond,triangledown,star,fsquare,fcircle,ftriangleup,fdiamond,bullet,dot,none,.,,,o,v,^,<,>,1,2,3,4,8,s,p,P,*,h,H,+,x,X,d,D,|,_,, ,None]
    </div>
    <br />
    <br />

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The following method returns the list of colors.

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.. code-block:: Python

    ot.Drawable.GetValidColors()[0:10]






.. raw:: html

    <div class="output_subarea output_html rendered_html output_result">
    [aliceblue,antiquewhite,antiquewhite1,antiquewhite2,antiquewhite3,antiquewhite4,aquamarine,aquamarine1,aquamarine2,aquamarine3]
    </div>
    <br />
    <br />

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In the following graph, we use the "aquamarine1" color with "fcircle" circles.

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.. code-block:: Python

    graph = ot.Graph("n=%d" % (n), "X1", "X2", True, "")
    cloud = ot.Cloud(sample)
    cloud.setColor("aquamarine1")
    cloud.setPointStyle("fcircle")
    graph.add(cloud)
    view = viewer.View(graph)




.. image-sg:: /auto_graphs/images/sphx_glr_plot_graphs_basics_006.png
   :alt: n=500
   :srcset: /auto_graphs/images/sphx_glr_plot_graphs_basics_006.png
   :class: sphx-glr-single-img





.. GENERATED FROM PYTHON SOURCE LINES 138-142

Configure the style of points and the thickness of a curve
----------------------------------------------------------

Assume that we want to plot the `sine` curve from -2 to 2. The simplest way is to use the `draw` method of the function.

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.. code-block:: Python

    g = ot.SymbolicFunction("x", "sin(x)")








.. GENERATED FROM PYTHON SOURCE LINES 147-150

.. code-block:: Python

    graph = g.draw(-2, 2)
    view = viewer.View(graph)




.. image-sg:: /auto_graphs/images/sphx_glr_plot_graphs_basics_007.png
   :alt: y0 as a function of x
   :srcset: /auto_graphs/images/sphx_glr_plot_graphs_basics_007.png
   :class: sphx-glr-single-img





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One would rather get a dashed curve: let us search for the available line styles.

.. GENERATED FROM PYTHON SOURCE LINES 154-157

.. code-block:: Python

    ot.Drawable.GetValidLineStyles()







.. raw:: html

    <div class="output_subarea output_html rendered_html output_result">
    [blank,solid,dashed,dotted,dotdash,longdash,twodash]
    </div>
    <br />
    <br />

.. GENERATED FROM PYTHON SOURCE LINES 158-159

In order to use the :class:`~openturns.Curve` class, it will be easier if we have a method to generate a :class:`~openturns.Sample` containing points regularly spaced in an interval.

.. GENERATED FROM PYTHON SOURCE LINES 162-171

.. code-block:: Python

    def linearSample(xmin, xmax, npoints):
        """Returns a sample created from a regular grid
        from xmin to xmax with npoints points."""
        step = (xmax - xmin) / (npoints - 1)
        rg = ot.RegularGrid(xmin, step, npoints)
        vertices = rg.getVertices()
        return vertices









.. GENERATED FROM PYTHON SOURCE LINES 172-175

.. code-block:: Python

    x = linearSample(-2, 2, 50)
    y = g(x)








.. GENERATED FROM PYTHON SOURCE LINES 176-184

.. code-block:: Python

    graph = ot.Graph("Sinus", "x", "sin(x)", True)
    curve = ot.Curve(x, y)
    curve.setLineStyle("dashed")
    curve.setLineWidth(4)
    graph.add(curve)
    view = viewer.View(graph)





.. image-sg:: /auto_graphs/images/sphx_glr_plot_graphs_basics_008.png
   :alt: Sinus
   :srcset: /auto_graphs/images/sphx_glr_plot_graphs_basics_008.png
   :class: sphx-glr-single-img





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Create colored curves
---------------------

In some situations, we want to create curves with different colors.
In this case, the following function generates a color corresponding to the `indexCurve` integer in a ensemble of `maximumNumberOfCurves` curves.

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.. code-block:: Python

    def createHSVColor(indexCurve, maximumNumberOfCurves):
        """Create a HSV color for the indexCurve-th curve
        from a sample with maximum size equal to maximumNumberOfCurves"""
        color = ot.Drawable.ConvertFromHSV(
            indexCurve * 360.0 / maximumNumberOfCurves, 1.0, 1.0
        )
        return color









.. GENERATED FROM PYTHON SOURCE LINES 203-205

.. code-block:: Python

    pofa = ot.HermiteFactory()








.. GENERATED FROM PYTHON SOURCE LINES 206-216

.. code-block:: Python

    graph = ot.Graph("Orthonormal Hermite polynomials", "x", "y", True, "lower right")
    degreemax = 5
    for k in range(degreemax):
        pk = pofa.build(k)
        curve = pk.draw(-3.0, 3.0, 50)
        curve.setLegends(["P%d" % (k)])
        curve.setColors([createHSVColor(k, degreemax)])
        graph.add(curve)
    view = viewer.View(graph)




.. image-sg:: /auto_graphs/images/sphx_glr_plot_graphs_basics_009.png
   :alt: Orthonormal Hermite polynomials
   :srcset: /auto_graphs/images/sphx_glr_plot_graphs_basics_009.png
   :class: sphx-glr-single-img





.. GENERATED FROM PYTHON SOURCE LINES 217-223

Create matrices of graphs
-------------------------

The library provides features to create a grid of graphs. However, we can use the `add_subplot` function from `Matplotlib`.

Let us create two graphs of the PDF and CDF of the following Normal distribution..

.. GENERATED FROM PYTHON SOURCE LINES 225-229

.. code-block:: Python

    n = ot.Normal()
    myPDF = n.drawPDF()
    myCDF = n.drawCDF()








.. GENERATED FROM PYTHON SOURCE LINES 230-231

Using `~openturns.GridLayout`.

.. GENERATED FROM PYTHON SOURCE LINES 231-236

.. code-block:: Python

    grid = ot.GridLayout(1, 2)
    grid.setGraph(0, 0, myPDF)
    grid.setGraph(0, 1, myCDF)
    _ = viewer.View(grid)




.. image-sg:: /auto_graphs/images/sphx_glr_plot_graphs_basics_010.png
   :alt: plot graphs basics
   :srcset: /auto_graphs/images/sphx_glr_plot_graphs_basics_010.png
   :class: sphx-glr-single-img





.. GENERATED FROM PYTHON SOURCE LINES 237-242

Another method is to create a figure with the `figure` function from `Matplotlib`,
then add two graphs with the `add_subplot` function.
We use the `viewer.View` function to create the required `Matplotlib` object.
Since we are not interested by the output of the `View` function, we use the dummy variable `_` as output.
The title is finally configured with `suptitle`.

.. GENERATED FROM PYTHON SOURCE LINES 244-251

.. code-block:: Python

    fig = plt.figure(figsize=(12, 4))
    ax_pdf = fig.add_subplot(1, 2, 1)
    _ = viewer.View(myPDF, figure=fig, axes=[ax_pdf])
    ax_cdf = fig.add_subplot(1, 2, 2)
    _ = viewer.View(myCDF, figure=fig, axes=[ax_cdf])
    _ = fig.suptitle("The gaussian")




.. image-sg:: /auto_graphs/images/sphx_glr_plot_graphs_basics_011.png
   :alt: The gaussian
   :srcset: /auto_graphs/images/sphx_glr_plot_graphs_basics_011.png
   :class: sphx-glr-single-img





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Save a plot into a file
-----------------------

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The :class:`openturns.viewer.View` class has a `save` method which saves the graph into an image.

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.. code-block:: Python

    n = ot.Normal()
    graph = n.drawPDF()
    view = viewer.View(graph)
    view.save("normal.png")




.. image-sg:: /auto_graphs/images/sphx_glr_plot_graphs_basics_012.png
   :alt: plot graphs basics
   :srcset: /auto_graphs/images/sphx_glr_plot_graphs_basics_012.png
   :class: sphx-glr-single-img





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We can use the `dpi` option to configure the resolution in dots per inch.

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.. code-block:: Python

    view.save("normal-100dpi.png", dpi=100)








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Configure the size of a graph with `matplotlib`
-----------------------------------------------

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We first create a graph containing the PDF of a Normal distribution

.. GENERATED FROM PYTHON SOURCE LINES 282-285

.. code-block:: Python

    n = ot.Normal()
    graph = n.drawPDF()








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The `figure_kw` keyword argument sets the optional arguments of the figure. In the following statement, we set the figure size in inches

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.. code-block:: Python

    view = viewer.View(graph, figure_kw={"figsize": (12, 8)})




.. image-sg:: /auto_graphs/images/sphx_glr_plot_graphs_basics_013.png
   :alt: plot graphs basics
   :srcset: /auto_graphs/images/sphx_glr_plot_graphs_basics_013.png
   :class: sphx-glr-single-img





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The `getFigure` method returns the current figure. This allows one to configure it as any other Matplotlib figure. In the following example, we configure the `suptitle`.

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.. code-block:: Python

    fig = view.getFigure()
    fig.suptitle("The suptitle")
    fig





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

 .. code-block:: none


    <Figure size 1200x800 with 1 Axes>



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The `plot_kw` optional argument sets the arguments of the plot. In the following example, we set the color of the plot in blue.

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.. code-block:: Python

    view = viewer.View(graph, plot_kw={"color": "blue"})
    plt.show()



.. image-sg:: /auto_graphs/images/sphx_glr_plot_graphs_basics_014.png
   :alt: plot graphs basics
   :srcset: /auto_graphs/images/sphx_glr_plot_graphs_basics_014.png
   :class: sphx-glr-single-img






.. _sphx_glr_download_auto_graphs_plot_graphs_basics.py:

.. only:: html

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

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

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

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

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

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

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