###########################
graphviz demo
###########################

- 在线 graphviz: https://dreampuf.github.io/GraphvizOnline/#digraph%20graphname%20%7B%20%0A%20%20%20%20node%5Bshape%3Dcircle%5D%0A%0A%0A%09%20%0A%7D
- 在线 graphviz: http://magjac.com/graphviz-visual-editor/



https://www.tonyballantyne.com/graphs.html#orgheadline12

https://candide-guevara.github.io/cs_related/2019/09/10/graphviz-examples.html


https://www.worthe-it.co.za/blog/2017-09-19-quick-introduction-to-graphviz.html

https://people.eecs.berkeley.edu/~jordan/graphical.html


布局
#################################

.. code-block:: rst

    .. digraph:: demo_1
          a -> {b c d}
          b -> {e f g}


.. digraph:: a1_1

      a -> {b c d}
      b -> {e f g}



.. code-block:: rst


    .. digraph:: demo_2

        rankdir=LR

        a -> {b c d}
        b -> {e f g}


.. digraph:: a1_2

    rankdir=LR

    a -> {b c d}
    b -> {e f g}




.. code-block:: rst

    .. digraph:: demo_3

        layout=neato

        a -> {b c d}
        b -> {e f g}



.. digraph:: a1_3

    layout=neato

    a -> {b c d}
    b -> {e f g}




.. code-block:: rst

    .. digraph:: demo_4

      layout=neato
      edge [len=0.8] # change edge length
      overlap=false  # prevents nodes from overlapping each other

      # These options MIGHT work on other implementations
      #overlap_scaling=0.5
      #overlap_shrink=true

      a -> {b c d}
      b -> {e f g}


.. digraph:: demo_4

  layout=neato
  edge [len=0.8] # change edge length
  overlap=false  # prevents nodes from overlapping each other

  # These options MIGHT work on other implementations
  #overlap_scaling=0.5
  #overlap_shrink=true

  a -> {b c d}
  b -> {e f g}



.. code-block:: rst

    .. digraph:: demo_5

        # A couple of option to expand/compress differently on x and y dimensions.
        layout=neato
        overlap=false # you NEED THIS for `sep` to take effect
        sep="+30,-5"  # expands 30 pixels on the x direction, but shrink y by 5

        a -> {b c d}
        b -> {e f g}


.. digraph:: demo_5

    # A couple of option to expand/compress differently on x and y dimensions.
    layout=neato
    overlap=false # you NEED THIS for `sep` to take effect
    sep="+30,-5"  # expands 30 pixels on the x direction, but shrink y by 5

    a -> {b c d}
    b -> {e f g}



.. code-block:: rst

    .. digraph:: demo_9

        newrank=true
        subgraph cluster_cl {
            a -> {b c}
        }
        r -> a
        b -> d
        # You can quickly get in WTF?! territory ...
        # You would expect that rank_d <= rank_r, but nope ...
        {rank=min d}


.. digraph:: demo_9

    newrank=true
    subgraph cluster_cl {
        a -> {b c}
    }
    r -> a
    b -> d
    # You can quickly get in WTF?! territory ...
    # You would expect that rank_d <= rank_r, but nope ...
    {rank=min d}




.. code-block:: rst

    .. digraph:: demo_10

        a -> {b c}
        # Heavy weight => short, straight and more vertical the edge.
        a -> d [weight=3]


.. digraph:: demo_10

    a -> {b c}
    # Heavy weight => short, straight and more vertical the edge.
    a -> d [weight=3]









其它
#################################


.. digraph:: 生成模型与判别模型
    :align: center
    :caption: （a）生成模型，对联合概率建模，然后推断出后验条件概率分布；（b）判别模型，直接对因子（ :math:`P(Y|X)` ）建模。

    node[shape=circle]

    subgraph cluster_1 {
        graph[labelloc="b", color=none ,label="(a)"];

        a_x1[label=<X<SUB>1</SUB>>]
        a_x2[label=<X<SUB>2</SUB>>]
        a_x3[label=<X<SUB>3</SUB>>]
        a_xh[label="..."  color=none ]

        a_xn[label=<X<SUB>n</SUB>>]
	    a_y[label=Y]

	    a_y -> a_xh[ style=invisible dir=none]
	    a_y -> {a_x1 a_x2 a_x3 a_xn}

    }

    subgraph cluster_2 {
        graph[labelloc="b", color=none ,label="(b)"];

        b_x1[label=<X<SUB>1</SUB>>]
        b_x2[label=<X<SUB>2</SUB>>]
        b_x3[label=<X<SUB>3</SUB>>]
        b_xh[label="..."  color=none ]

        b_xn[label=<X<SUB>n</SUB>>]
	    b_y[label=Y]

	    b_s1[shape=box label="" width=0.1 height=0.1 ]
	    b_s2[shape=box label="" width=0.1 height=0.1 ]
	    b_s3[shape=box label="" width=0.1 height=0.1 ]
	    b_sh[shape=box label="" width=0.1 height=0.1,color=none ]
	    b_sn[shape=box label="" width=0.1 height=0.1 ]

	    b_y -> b_sh[ style=invisible dir=none]
	    b_y -> {b_s1 b_s2 b_s3 b_sn}[dir=none shape=obox ]
	    b_s1 -> b_x1[dir=none]
	    b_s2 -> b_x2[dir=none shape=box ]
	    b_s3 -> b_x3[dir=none]
	    b_sn -> b_xn[dir=none]
	    b_sh -> b_xh[dir=none style=invisible]

	    {rank="same"; b_x1 b_x2 b_x3 b_xh b_xn}
    }