Utilizar nuevas extensiones para mejorar las figuras

Además completa algunos comentarios sobre las figuras y otros
detalles.

diff --git a/source/conf.py b/source/conf.py
index bbf1ec07448cd67a24774bbce811f5cb11577d4a..db52cc904a48b9fdece4378ea0fd5f62f78d2c54 100644 (file)
--- a/source/conf.py
+++ b/source/conf.py
@@ -22,7 +22,7 @@ sys.path.append(os.path.abspath('../ext'))
 
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
 
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.

-extensions = ['graphviz', 'sphinx.ext.pngmath']
+extensions = ['fig', 'vref', 'graphviz', 'sphinx.ext.pngmath']

 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['.templates']
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['.templates']


@@ -186,6 +186,7 @@ latex_logo = 'fiuba.png'
 
 # Additional stuff for the LaTeX preamble.
 latex_preamble = r'''
 
 # Additional stuff for the LaTeX preamble.
 latex_preamble = r'''

+\usepackage{varioref}

 \usepackage{subfigure}
 \setcounter{tocdepth}{3}
 '''
 \usepackage{subfigure}
 \setcounter{tocdepth}{3}
 '''

diff --git a/source/gc.rst b/source/gc.rst
index 100614f6c537ddc5df723237110ee4bd50e5aea5..94ab86cf826fecd7578e7a4a739106b64c9d6de2 100644 (file)
--- a/source/gc.rst
+++ b/source/gc.rst
@@ -4,7 +4,6 @@
    un breve recorrido sobre el estado del arte.
    ESTADO: SIN EMPEZAR
 
    un breve recorrido sobre el estado del arte.
    ESTADO: SIN EMPEZAR
 

-

 .. _ref_gc:
 
 Recolección de basura
 .. _ref_gc:
 
 Recolección de basura


@@ -244,71 +243,67 @@ Más formalmente, Definimos:
 
       Basura = V - Live \thickspace set
 
 
       Basura = V - Live \thickspace set
 

-Esto es, efectivamente, una partición del *heap*.
-
-.. TODO: figure
+Esto es, efectivamente, una partición del *heap* (ver figura
+:vref:`fig:gc-heap-parts`).

 
 

-.. raw:: latex

 
 

-   \begin{figure}[htp] \centering
+.. fig:: fig:gc-heap-parts

 
 

-.. digraph:: g1
+   Distintas partes de la memoria, incluyendo relación entre *basura*,
+   *live set*, *heap* y *root set*.

 
 

-   margin  = 0;
-   ratio   = fill;
-   size    = "4.6,3.6";
-   node [ shape = record, width = 0, height = 0 ];
+   .. digraph:: g1

 
 

-   subgraph cluster_heap {
-      label = "Heap";
-      style     = dashed;
-      color     = gray40;
-      fontcolor = gray40;
+      margin  = 0;
+      ratio   = fill;
+      size    = "4.6,3.6";
+      node [ shape = record, width = 0, height = 0 ];

 
 

-      subgraph cluster_live {
-         label     = "Live set";
+      subgraph cluster_heap {
+         label = "Heap";

          style     = dashed;
          color     = gray40;
          fontcolor = gray40;
          style     = dashed;
          color     = gray40;
          fontcolor = gray40;

-         node [
-            style     = filled,
-            fillcolor = gray25,
-            fontcolor = white,
-         ];
-         h1; h2; h4; h5; h6;
+
+         subgraph cluster_live {
+            label     = "Live set";
+            style     = dashed;
+            color     = gray40;
+            fontcolor = gray40;
+            node [
+               style     = filled,
+               fillcolor = gray25,
+               fontcolor = white,
+            ];
+            h1; h2; h4; h5; h6;
+         }
+
+         subgraph cluster_garbage {
+            label     = "Basura";
+            style     = dashed;
+            color     = gray40;
+            fontcolor = gray40;
+            node [ style = filled, fillcolor = white ];
+            h7; h3;
+         }

       }
 
       }
 

-      subgraph cluster_garbage {
-         label     = "Basura";
+      subgraph cluster_root {
+         label     = "Root set";

          style     = dashed;
          color     = gray40;
          fontcolor = gray40;
          style     = dashed;
          color     = gray40;
          fontcolor = gray40;

-         node [ style = filled, fillcolor = white ];
-         h7; h3;
+         node [ style = filled, fillcolor = gray96 ];
+         r0; r1; r2;

       }
       }

-   }
-
-   subgraph cluster_root {
-      label     = "Root set";
-      style     = dashed;
-      color     = gray40;
-      fontcolor = gray40;
-      node [ style = filled, fillcolor = gray96 ];
-      r0; r1; r2;
-   }
-
-   r0 -> h1 -> h2 -> h5;
-   r1 -> h5 -> h6 -> h1;
-   r2 -> h4;
-   h5 -> h4;
-   h7 -> h1;
-   h7 -> h3;
-
-.. raw:: latex
-
-   \caption{Distintas partes de la memoria, incluyendo relación entre
-   basura, live set, heap y root set.}
-   \end{figure}
+
+      r0 -> h1 -> h2 -> h5;
+      r1 -> h5 -> h6 -> h1;
+      r2 -> h4;
+      h5 -> h4;
+      h7 -> h1;
+      h7 -> h3;
+

 
 Al proceso de visitar los vértices *conectados* desde el *root set* se lo
 denomina *marcado*, *fase de marcado* o *mark phase* en inglés, debido
 
 Al proceso de visitar los vértices *conectados* desde el *root set* se lo
 denomina *marcado*, *fase de marcado* o *mark phase* en inglés, debido


@@ -342,235 +337,234 @@ Esto es conocido también como **abstracción bicolor**, dado que en la
 literatura se habla muchas veces de *colorear* las celdas. En general, una
 celda sin marcar es de color blanco y una marcada de color negro.
 
 literatura se habla muchas veces de *colorear* las celdas. En general, una
 celda sin marcar es de color blanco y una marcada de color negro.
 

-.. TODO: figure
+Puede observarse un ejemplo del algoritmo en la figura
+:vref:`fig:gc-mark-1`, en la cual se marca el sub-grafo apuntando por
+``r0``. Luego se marca el sub-grafo al que apunta ``r1`` (figura
+:vref:`fig:gc-mark-2`), concluyendo con el marcado del grafo completo,
+dejando sin marcar solamente las celdas *basura* (en blanco).
+
+
+.. fig:: fig:gc-mark-1
+
+   Ejemplo de marcado del grafo de conectividad (parte 1).

 
 

-.. raw:: latex
+   .. subfig::

 
 

-   \begin{figure}[htp]
-   \centering
-   \subfigure[TODO texto más largo y más largo y larguísimo porque tiene
-   muchas cosas que decir]{
+      Se comienza a marcar el grafo por la raíz r0.

 
 

-.. digraph:: g2_1
+      .. digraph:: g2_1

 
 

-   margin = 0;
-   ratio  = fill;
-   size   = "2.0,2.6";
-   node [ shape = record, width = 0, height = 0];
-   edge [ color = gray40 ];
+         margin = 0;
+         ratio  = fill;
+         size   = "1.9,2.6";
+         node [ shape = record, width = 0, height = 0];
+         edge [ color = gray40 ];

 
 

-   subgraph cluster_all {
+         subgraph cluster_all {

 
 

-      root [
-         label     = "root\nset|<r0> r0\n*|<r1> r1",
-         style     = filled,
-         fillcolor = gray96,
-      ];
+            root [
+               label     = "root\nset|<r0> r0\n*|<r1> r1",
+               style     = filled,
+               fillcolor = gray96,
+            ];

 
 

-      subgraph marked {
-         node [ style = filled, fillcolor = gray25, fontcolor = white ];
-         h1;
-      };
+            subgraph marked {
+               node [ style = filled, fillcolor = gray25, fontcolor = white ];
+               h1;
+            };

 
 

-      root:r0 -> h1 [ style = bold, color = black ];
-      h1 -> h2 -> h5 -> h1;
-      root:r1 -> h6 -> h2;
-      h4 -> h3;
-      h3 -> h5;
+            root:r0 -> h1 [ style = bold, color = black ];
+            h1 -> h2 -> h5 -> h1;
+            root:r1 -> h6 -> h2;
+            h4 -> h3;
+            h3 -> h5;

 
 

-   }
+         }

 
 

-.. raw:: latex
+   .. subfig::

 
 

-   }
-   \subfigure[TODO]{
+      Luego de marcar el nodo ``h1``, se procede al ``h2``.

 
 

-.. digraph:: g2_2
+      .. digraph:: g2_2

 
 

-   margin = 0;
-   ratio  = fill;
-   size   = "2.0,2.6";
-   node [ shape = record, width = 0, height = 0 ];
-   edge [ color = gray40 ];
+         margin = 0;
+         ratio  = fill;
+         size   = "1.9,2.6";
+         node [ shape = record, width = 0, height = 0 ];
+         edge [ color = gray40 ];

 
 

-   subgraph cluster_all {
+         subgraph cluster_all {

 
 

-      root [
-         label     = "root\nset|<r0> r0\n*|<r1> r1",
-         style     = filled,
-         fillcolor = gray96,
-      ];
+            root [
+               label     = "root\nset|<r0> r0\n*|<r1> r1",
+               style     = filled,
+               fillcolor = gray96,
+            ];

 
 

-      subgraph marked {
-         node [ style = filled, fillcolor = gray25, fontcolor = white ];
-         h1; h2;
-      };
+            subgraph marked {
+               node [ style = filled, fillcolor = gray25, fontcolor = white ];
+               h1; h2;
+            };

 
 

-      root:r0 -> h1 [ color = gray10 ];
-      h1 -> h2 [ style = bold, color = black ];
-      h2 -> h5 -> h1;
-      root:r1 -> h6 -> h2;
-      h4 -> h3;
-      h3 -> h5;
+            root:r0 -> h1 [ color = gray10 ];
+            h1 -> h2 [ style = bold, color = black ];
+            h2 -> h5 -> h1;
+            root:r1 -> h6 -> h2;
+            h4 -> h3;
+            h3 -> h5;

 
 

-   }
+         }

 
 

-.. raw:: latex
+   .. subfig::

 
 

-   }
-   \subfigure[TODO]{
+      Luego sigue el nodo h5.

 
 

-.. digraph:: g2_3
+      .. digraph:: g2_3

 
 

-   margin = 0;
-   ratio  = fill;
-   size   = "2.0,2.6";
-   node [ shape = record, width = 0, height = 0 ];
-   edge [ color = gray40 ];
+         margin = 0;
+         ratio  = fill;
+         size   = "1.9,2.6";
+         node [ shape = record, width = 0, height = 0 ];
+         edge [ color = gray40 ];

 
 

-   subgraph cluster_all {
+         subgraph cluster_all {

 
 

-      root [
-         label     = "root\nset|<r0> r0\n*|<r1> r1",
-         style     = filled,
-         fillcolor = gray96,
-      ];
+            root [
+               label     = "root\nset|<r0> r0\n*|<r1> r1",
+               style     = filled,
+               fillcolor = gray96,
+            ];

 
 

-      subgraph marked {
-         node [ style = filled, fillcolor = gray25, fontcolor = white ];
-         h1; h2; h5;
-      };
+            subgraph marked {
+               node [ style = filled, fillcolor = gray25, fontcolor = white ];
+               h1; h2; h5;
+            };

 
 

-      root:r0 -> h1 [ color = gray10 ];
-      h1 -> h2 [ color = gray10 ];
-      h2 -> h5 [ style = bold, color = black ];
-      h5 -> h1;
-      root:r1 -> h6 -> h2;
-      h4 -> h3;
-      h3 -> h5;
+            root:r0 -> h1 [ color = gray10 ];
+            h1 -> h2 [ color = gray10 ];
+            h2 -> h5 [ style = bold, color = black ];
+            h5 -> h1;
+            root:r1 -> h6 -> h2;
+            h4 -> h3;
+            h3 -> h5;

 
 

-   }
+         }

 
 

-.. raw:: latex

 
 

-   }
-   \caption{TODO, part 1}
-   \end{figure}
+.. fig:: fig:gc-mark-2

 
 

-   \begin{figure}[htp]
-   \centering
-   \subfigure[TODO]{
-
-.. digraph:: g2_4
-
-   margin = 0;
-   ratio  = fill;
-   size   = "2.0,2.6";
-   node [ shape = record, width = 0, height = 0 ];
-   edge [ color = gray40 ];
+   Ejemplo de marcado del grafo de conectividad (parte 2).

 
 

-   subgraph cluster_all {
+   .. subfig::

 
 

-      root [
-         label     = "root\nset|<r0> r0\n*|<r1> r1",
-         style     = filled,
-         fillcolor = gray96,
-      ];
+      El nodo h5 tiene una arista al h1, pero el h1 ya fue visitado, por lo
+      tanto no se visita nuevamente.

 
 

-      subgraph marked {
-         node [ style = filled, fillcolor = gray25, fontcolor = white ];
-         h1; h2; h5;
-      };
+      .. digraph:: g2_4

 
 

-      root:r0 -> h1 [ color = gray10 ];
-      h1 -> h2 [ color = gray10 ];
-      h2 -> h5 [ color = gray10 ];
-      h5 -> h1 [ style = bold, color = black ];
-      root:r1 -> h6 -> h2;
-      h4 -> h3;
-      h3 -> h5;
+         margin = 0;
+         ratio  = fill;
+         size   = "1.9,2.6";
+         node [ shape = record, width = 0, height = 0 ];
+         edge [ color = gray40 ];

 
 

-   }
+         subgraph cluster_all {

 
 

-.. raw:: latex
+            root [
+               label     = "root\nset|<r0> r0\n*|<r1> r1",
+               style     = filled,
+               fillcolor = gray96,
+            ];

 
 

-   }
-   \subfigure[TODO]{
+            subgraph marked {
+               node [ style = filled, fillcolor = gray25, fontcolor = white ];
+               h1; h2; h5;
+            };

 
 

-.. digraph:: g2_5
+            root:r0 -> h1 [ color = gray10 ];
+            h1 -> h2 [ color = gray10 ];
+            h2 -> h5 [ color = gray10 ];
+            h5 -> h1 [ style = bold, color = black ];
+            root:r1 -> h6 -> h2;
+            h4 -> h3;
+            h3 -> h5;

 
 

-   margin = 0;
-   ratio  = fill;
-   size   = "2.0,2.6";
-   node [ shape = record, width = 0, height = 0 ];
-   edge [ color = gray40 ];
+         }

 
 

-   subgraph cluster_all {
+   .. subfig::

 
 

-     root [
-        label     = "root\nset|<r0> r0|<r1> r1\n*",
-        style     = filled,
-        fillcolor = gray96,
-     ];
+      Se concluye el marcado del sub-grafo al que conecta r0, se procede
+      a marcar el sub-grafo al que conecta r1, marcando al nodo h6.

 
 

-     subgraph marked {
-        node [ style = filled, fillcolor = gray25, fontcolor = white ];
-        h1; h2; h5; h6;
-     };
+      .. digraph:: g2_5

 
 

-     root:r0 -> h1 [ color = gray10 ];
-     h1 -> h2 [ color = gray10 ];
-     h2 -> h5 [ color = gray10 ];
-     h5 -> h1 [ color = gray10 ];
-     root:r1 -> h6 [ style = bold, color = black ];
-     h6 -> h2;
-     h4 -> h3;
-     h3 -> h5;
+         margin = 0;
+         ratio  = fill;
+         size   = "1.9,2.6";
+         node [ shape = record, width = 0, height = 0 ];
+         edge [ color = gray40 ];

 
 

-   }
+         subgraph cluster_all {

 
 

-.. raw:: latex
+           root [
+              label     = "root\nset|<r0> r0|<r1> r1\n*",
+              style     = filled,
+              fillcolor = gray96,
+           ];

 
 

-   }
-   \subfigure[TODO]{
+           subgraph marked {
+              node [ style = filled, fillcolor = gray25, fontcolor = white ];
+              h1; h2; h5; h6;
+           };

 
 

-.. digraph:: g2_6
+           root:r0 -> h1 [ color = gray10 ];
+           h1 -> h2 [ color = gray10 ];
+           h2 -> h5 [ color = gray10 ];
+           h5 -> h1 [ color = gray10 ];
+           root:r1 -> h6 [ style = bold, color = black ];
+           h6 -> h2;
+           h4 -> h3;
+           h3 -> h5;

 
 

-   margin = 0;
-   ratio  = fill;
-   size   = "2.0,2.6";
-   node [ shape = record, width = 0, height = 0 ];
-   edge [ color = gray40 ];
+         }

 
 

-   subgraph cluster_all {
+   .. subfig::

 
 

-      root [
-         label     = "root\nset|<r0> r0|<r1> r1\n*",
-         style     = filled,
-         fillcolor = gray96,
-      ];
+      El nodo h6 tiene una arista al h2, pero éste ya fue marcado por lo
+      que no se vuelve a visitar. No hay más raíces, se finaliza el marcado
+      del grafo.

 
 

-      subgraph marked {
-         node [ style = filled, fillcolor = gray25, fontcolor = white ];
-         h1; h2; h5; h6;
-      };
+      .. digraph:: g2_6

 
 

-      root:r0 -> h1 [ color = gray10 ];
-      h1 -> h2 [ color = gray10 ];
-      h2 -> h5 [ color = gray10 ];
-      h5 -> h1 [ color = gray10 ];
-      root:r1 -> h6 [ color = gray10 ];
-      h6 -> h2 [ style = bold, color = black ];
-      h4 -> h3;
-      h3 -> h5;
+         margin = 0;
+         ratio  = fill;
+         size   = "1.9,2.6";
+         node [ shape = record, width = 0, height = 0 ];
+         edge [ color = gray40 ];

 
 

-   }
+         subgraph cluster_all {

 
 

-.. raw:: latex
+            root [
+               label     = "root\nset|<r0> r0|<r1> r1\n*",
+               style     = filled,
+               fillcolor = gray96,
+            ];

 
 

-   }
-   \caption{TODO, parte 2}
-   \end{figure}
+            subgraph marked {
+               node [ style = filled, fillcolor = gray25, fontcolor = white ];
+               h1; h2; h5; h6;
+            };
+
+            root:r0 -> h1 [ color = gray10 ];
+            h1 -> h2 [ color = gray10 ];
+            h2 -> h5 [ color = gray10 ];
+            h5 -> h1 [ color = gray10 ];
+            root:r1 -> h6 [ color = gray10 ];
+            h6 -> h2 [ style = bold, color = black ];
+            h4 -> h3;
+            h3 -> h5;
+
+         }

 
 
 .. [#gccycle] Un ciclo es un camino donde el *vértice inicial* es el mismo
 
 
 .. [#gccycle] Un ciclo es un camino donde el *vértice inicial* es el mismo


@@ -810,552 +804,569 @@ Ejemplo
 ^^^^^^^
 
 A continuación se presenta un ejemplo gráfico para facilitar la comprensión
 ^^^^^^^
 
 A continuación se presenta un ejemplo gráfico para facilitar la comprensión

-del algoritmo.
-
-Por simplicidad se asumen celdas de tamaño fijo con dos punteros, ``left``
-y ``right`` (estructura clásica para representar un árbol binario) y se
-muestra el contador de referencias abajo del nombre de cada celda. Se parte
-con una pequeña estructura ya construída y se muestra primero lo que ocurre
-al eliminar la referencia :math:`r0 \to h1`:
-
-.. TODO: figure
-
-.. raw:: latex
-
-   \begin{figure}[htp]
-   \centering
-   \subfigure[TODO]{
-
-.. digraph:: g3_1
-
-   margin = 0;
-   ratio  = fill;
-   size   = "3.0,3.8";
-   edge [ color = gray40 ];
-   node [
-      shape     = record,
-      width     = 0,
-      height    = 0,
-      style     = filled,
-      fillcolor = gray25,
-      fontcolor = white
-   ];
-
-   subgraph cluster_all {
-
-      root [
-         label     = "root\nset|<r0> r0\n*|<r1> r1",
-         style     = filled,
-         fillcolor = gray96,
-         fontcolor = black,
-      ];
-
-      h1 [ label = "h1\n1|<l> left|<r> right" ];
-      h2 [ label = "h2\n2|<l> left|<r> right" ];
-      h3 [ label = "h3\n2|<l> left|<r> right" ];
-      h4 [ label = "h4\n1|<l> left|<r> right" ];
-      h5 [ label = "h5\n1|<l> left|<r> right" ];
-      h6 [ label = "h6\n1|<l> left|<r> right" ];
-
-      root:r0 -> h1 [ style = bold, color = black ];
-      root:r1 -> h3;
-      h1:l -> h2;
-      h1:r -> h3;
-      h2:l -> h4;
-      h2:r -> h5;
-      h3:l -> h2;
-      h3:r -> h6;
-
-   }
-
-.. raw:: latex
-
-   }
-   \subfigure[TODO]{
-
-.. digraph:: g3_2
-
-   margin = 0;
-   ratio  = fill;
-   size   = "3.0,3.8";
-   edge [ color = gray40 ];
-   node [
-      shape     = record,
-      width     = 0,
-      height    = 0,
-      style     = filled,
-      fillcolor = gray25,
-      fontcolor = white
-   ];
-
-   subgraph cluster_all {
-
-      root [
-         label     = "root\nset|<r0> r0\n*|<r1> r1",
-         style     = filled,
-         fillcolor = gray96,
-         fontcolor = black,
-      ];
-
-      subgraph marked {
-         node [ fillcolor = white, fontcolor = black ];
-         h1;
-      };
-
-      h1 [ label = "h1\n0|<l> left|<r> right" ];
-      h2 [ label = "h2\n2|<l> left|<r> right" ];
-      h3 [ label = "h3\n2|<l> left|<r> right" ];
-      h4 [ label = "h4\n1|<l> left|<r> right" ];
-      h5 [ label = "h5\n1|<l> left|<r> right" ];
-      h6 [ label = "h6\n1|<l> left|<r> right" ];
-
-      root:r0 -> h1 [ style = invis ];
-      root:r1 -> h3;
-      h1:l -> h2 [ style = bold, color = black ];
-      h1:r -> h3;
-      h2:l -> h4;
-      h2:r -> h5;
-      h3:l -> h2;
-      h3:r -> h6;
-
-   }
-
-.. raw:: latex
-
-   }
-   \caption{TODO, part 1}
-   \end{figure}
-
-   \begin{figure}[htp]
-   \centering
-   \subfigure[TODO]{
-
-.. digraph:: g3_3
-
-   margin = 0;
-   ratio  = fill;
-   size   = "3.0,3.8";
-   edge [ color = gray40 ];
-   node [
-      shape     = record,
-      width     = 0,
-      height    = 0,
-      style     = filled,
-      fillcolor = gray25,
-      fontcolor = white
-   ];
-
-   subgraph cluster_all {
-
-      root [
-         label     = "root\nset|<r0> r0\n*|<r1> r1",
-         style     = filled,
-         fillcolor = gray96,
-         fontcolor = black,
-      ];
-
-      subgraph marked {
-         node [ fillcolor = white, fontcolor = black ];
-         h1;
-      };
-
-      h1 [ label = "h1\n0|<l> left|<r> right" ];
-      h2 [ label = "h2\n1|<l> left|<r> right" ];
-      h3 [ label = "h3\n2|<l> left|<r> right" ];
-      h4 [ label = "h4\n1|<l> left|<r> right" ];
-      h5 [ label = "h5\n1|<l> left|<r> right" ];
-      h6 [ label = "h6\n1|<l> left|<r> right" ];
-
-      root:r0 -> h1 [ style = invis ];
-      root:r1 -> h3;
-      h1:l -> h2 [ style = invis ];
-      h1:r -> h3 [ style = bold, color = black ];
-      h2:l -> h4;
-      h2:r -> h5;
-      h3:l -> h2;
-      h3:r -> h6;
-
-   }
-
-.. raw:: latex
-
-   }
-   \subfigure[TODO]{
-
-.. digraph:: g3_4
-
-   margin = 0;
-   ratio  = fill;
-   size   = "3.0,3.8";
-   edge [ color = gray40 ];
-   node [
-      shape     = record,
-      width     = 0,
-      height    = 0,
-      style     = filled,
-      fillcolor = gray25,
-      fontcolor = white
-   ];
-
-   subgraph cluster_all {
-
-      root [
-         label     = "root\nset|<r0> r0|<r1> r1",
-         style     = filled,
-         fillcolor = gray96,
-         fontcolor = black,
-      ];
-
-      subgraph marked {
-         node [ fillcolor = white, fontcolor = black ];
-         h1;
-      };
-
-      h1 [ label = "h1\n0|<l> left|<r> right" ];
-      h2 [ label = "h2\n1|<l> left|<r> right" ];
-      h3 [ label = "h3\n1|<l> left|<r> right" ];
-      h4 [ label = "h4\n1|<l> left|<r> right" ];
-      h5 [ label = "h5\n1|<l> left|<r> right" ];
-      h6 [ label = "h6\n1|<l> left|<r> right" ];
-
-      root:r0 -> h1 [ style = invis ];
-      root:r1 -> h3;
-      h1:l -> h2 [ style = invis ];
-      h1:r -> h3 [ style = invis ];
-      h2:l -> h4;
-      h2:r -> h5;
-      h3:l -> h2;
-      h3:r -> h6;
-
-   }
-
-.. raw:: latex
-
-   }
-   \caption{TODO, parte 2}
-   \end{figure}
-
-Como se observa, la celda ``h1`` queda con el contador en 0, por lo tanto
-pasa a ser *basura*. Los contadores de las celdas a las que apuntaban
-``h1.left`` y ``h1.right`` son decrementados, pero no se detecta más basura
-porque sigue existiendo un camino del *root set* a aquellas celdas, y por
-transitividad a todas aquellas celdas apuntadas por éstas. Es por esto que
-no es necesario seguir recorriendo el grafo de conectividad.
-
-A continuación se muestra como opera el algoritmo al cambiar a donde apunta
-``h3.left``, haciéndola apuntar a ``h5``. Es decir, que pasa luego de la
-operación ``update(h3.left, h5)`` (por simplicidad no se muestra más la
-celda ``h1`` que ahora es *basura*):
-
-.. TODO: figure
-
-.. raw:: latex
-
-   \begin{figure}[htp]
-   \centering
-   \subfigure[TODO]{
-
-.. digraph:: g4_1
-
-   margin = 0;
-   ratio  = fill;
-   size   = "3.0,3.8";
-   edge [ color = gray40 ];
-   node [
-      shape     = record,
-      width     = 0,
-      height    = 0,
-      style     = filled,
-      fillcolor = gray25,
-      fontcolor = white
-   ];
-
-   subgraph cluster_all {
-
-      root [
-         label     = "root\nset|<r0> r0|<r1> r1",
-         style     = filled,
-         fillcolor = gray96,
-         fontcolor = black,
-      ];
-
-      subgraph marked {
-         node [ fillcolor = white, fontcolor = black ];
-      };
-
-      h2 [ label = "h2\n1|<l> left|<r> right" ];
-      h3 [ label = "h3\n1|<l> left\n*|<r> right" ];
-      h4 [ label = "h4\n1|<l> left|<r> right" ];
-      h5 [ label = "h5\n1|<l> left|<r> right" ];
-      h6 [ label = "h6\n1|<l> left|<r> right" ];
-
-      root:r1 -> h3;
-      h2:l -> h4;
-      h2:r -> h5;
-      h3:l -> h2 [ style = bold, color = black ];
-      h3:r -> h6;
-
-   }
-
-.. raw:: latex
-
-   }
-   \subfigure[TODO]{
-
-.. digraph:: g4_2
-
-   margin = 0;
-   ratio  = fill;
-   size   = "3.0,3.8";
-   edge [ color = gray40 ];
-   node [
-      shape     = record,
-      width     = 0,
-      height    = 0,
-      style     = filled,
-      fillcolor = gray25,
-      fontcolor = white
-   ];
-
-   subgraph cluster_all {
-
-      root [
-         label     = "root\nset|<r0> r0|<r1> r1",
-         style     = filled,
-         fillcolor = gray96,
-         fontcolor = black,
-      ];
-
-      subgraph marked {
-         node [ fillcolor = white, fontcolor = black ];
-      };
-
-      h2 [ label = "h2\n1|<l> left|<r> right" ];
-      h3 [ label = "h3\n1|<l> left\n*|<r> right" ];
-      h4 [ label = "h4\n1|<l> left|<r> right" ];
-      h5 [ label = "h5\n2|<l> left|<r> right" ];
-      h6 [ label = "h6\n1|<l> left|<r> right" ];
-
-      root:r1 -> h3;
-      h2:l -> h4;
-      h2:r -> h5;
-      h3:l -> h2 [ style = bold, color = black ];
-      h3:l -> h5 [ style = dotted, color = black ];
-      h3:r -> h6;
-
-   }
-
-.. raw:: latex
-
-   }
-   \caption{TODO, part 1}
-   \end{figure}
-
-   \begin{figure}[htp]
-   \centering
-   \subfigure[TODO]{
-
-.. digraph:: g4_3
-
-   margin = 0;
-   ratio  = fill;
-   size   = "3.0,3.8";
-   edge [ color = gray40 ];
-   node [
-      shape     = record,
-      width     = 0,
-      height    = 0,
-      style     = filled,
-      fillcolor = gray25,
-      fontcolor = white
-   ];
-
-   subgraph cluster_all {
-
-      root [
-         label     = "root\nset|<r0> r0|<r1> r1",
-         style     = filled,
-         fillcolor = gray96,
-         fontcolor = black,
-      ];
-
-      subgraph marked {
-         node [ fillcolor = white, fontcolor = black ];
-         h2;
-      };
-
-      h2 [ label = "h2\n0|<l> left|<r> right" ];
-      h3 [ label = "h3\n1|<l> left\n*|<r> right" ];
-      h4 [ label = "h4\n1|<l> left|<r> right" ];
-      h5 [ label = "h5\n2|<l> left|<r> right" ];
-      h6 [ label = "h6\n1|<l> left|<r> right" ];
-
-      root:r1 -> h3;
-      h2:l -> h4 [ style = bold, color = black ];
-      h2:r -> h5;
-      h3:l -> h2 [ style = invis ];
-      h3:l -> h5 [ style = dotted, color = black ];
-      h3:r -> h6;
-
-   }
-
-.. raw:: latex
-
-   }
-   \subfigure[TODO]{
-
-.. digraph:: g4_4
-
-   margin = 0;
-   ratio  = fill;
-   size   = "3.0,3.8";
-   edge [ color = gray40 ];
-   node [
-      shape     = record,
-      width     = 0,
-      height    = 0,
-      style     = filled,
-      fillcolor = gray25,
-      fontcolor = white
-   ];
-
-   subgraph cluster_all {
-
-      root [
-         label     = "root\nset|<r0> r0|<r1> r1",
-         style     = filled,
-         fillcolor = gray96,
-         fontcolor = black,
-      ];
-
-      subgraph marked {
-         node [ fillcolor = white, fontcolor = black ];
-         h2; h4;
-      };
-
-      h2 [ label = "h2\n0|<l> left|<r> right" ];
-      h3 [ label = "h3\n1|<l> left\n*|<r> right" ];
-      h4 [ label = "h4\n0|<l> left|<r> right" ];
-      h5 [ label = "h5\n2|<l> left|<r> right" ];
-      h6 [ label = "h6\n1|<l> left|<r> right" ];
-
-      root:r1 -> h3;
-      h2:l -> h4 [ style = invis ];
-      h2:r -> h5 [ style = bold, color = black ];
-      h3:l -> h2 [ style = invis ];
-      h3:l -> h5 [ style = dotted, color = black ];
-      h3:r -> h6;
-
-   }
-
-.. raw:: latex
-
-   }
-   \caption{TODO, part 2}
-   \end{figure}
-
-   \begin{figure}[htp]
-   \centering
-   \subfigure[TODO]{
-
-.. digraph:: g4_5
-
-   margin = 0;
-   ratio  = fill;
-   size   = "3.0,3.8";
-   edge [ color = gray40 ];
-   node [
-      shape     = record,
-      width     = 0,
-      height    = 0,
-      style     = filled,
-      fillcolor = gray25,
-      fontcolor = white
-   ];
-
-   subgraph cluster_all {
-
-      root [
-         label     = "root\nset|<r0> r0|<r1> r1",
-         style     = filled,
-         fillcolor = gray96,
-         fontcolor = black,
-      ];
-
-      subgraph marked {
-         node [ fillcolor = white, fontcolor = black ];
-         h2; h4;
-      };
-
-      h2 [ label = "h2\n0|<l> left|<r> right" ];
-      h3 [ label = "h3\n1|<l> left\n*|<r> right" ];
-      h4 [ label = "h4\n0|<l> left|<r> right" ];
-      h5 [ label = "h5\n1|<l> left|<r> right" ];
-      h6 [ label = "h6\n1|<l> left|<r> right" ];
-
-      root:r1 -> h3;
-      h2:l -> h4 [ style = invis ];
-      h2:r -> h5 [ style = invis ];
-      h3:l -> h5 [ style = bold, color = black ];
-      h3:l -> h2 [ style = invis ];
-      h3:r -> h6;
-
-   }
-
-.. raw:: latex
-
-   }
-   \subfigure[TODO]{
-
-.. digraph:: g4_6
-
-   margin = 0;
-   ratio  = fill;
-   size   = "3.0,3.8";
-   edge [ color = gray40 ];
-   node [
-      shape     = record,
-      width     = 0,
-      height    = 0,
-      style     = filled,
-      fillcolor = gray25,
-      fontcolor = white
-   ];
-
-   subgraph cluster_all {
-
-      root [
-         label     = "root\nset|<r0> r0|<r1> r1",
-         style     = filled,
-         fillcolor = gray96,
-         fontcolor = black,
-      ];
-
-      subgraph marked {
-         node [ fillcolor = white, fontcolor = black ];
-         h2; h4;
-      };
-
-      h2 [ label = "h2\n0|<l> left|<r> right" ];
-      h3 [ label = "h3\n1|<l> left|<r> right" ];
-      h4 [ label = "h4\n0|<l> left|<r> right" ];
-      h5 [ label = "h5\n1|<l> left|<r> right" ];
-      h6 [ label = "h6\n1|<l> left|<r> right" ];
-
-      root:r1 -> h3;
-      h2:l -> h4 [ style = invis ];
-      h2:r -> h5 [ style = invis ];
-      h3:l -> h5;
-      h3:l -> h2 [ style = invis ];
-      h3:r -> h6;
-
-   }
-
-.. raw:: latex
-
-   }
-   \caption{TODO, parte 3}
-   \end{figure}
+del algoritmo. Por simplicidad se asumen celdas de tamaño fijo con dos
+punteros, ``left`` y ``right`` y se muestra el contador de referencias
+abajo del nombre de cada celda. Se parte con una pequeña estructura ya
+construída y se muestra como opera el algoritmo al eliminar o cambiar una
+referencia (cambios en la conectividad del grafo).
+
+Se comienza por eliminar la referencia de ``r0`` a ``h1``, que determina
+que ``h1`` se convirtió en *basura* (figura :vref:`fig:gc-rc-rm-1`). Esto
+conduce al decremento del contador de ``h2`` y ``h3`` que permanecen en el
+*live set* ya que sus contadores siguen siendo mayores a 0 (figura
+:vref:`fig:gc-rc-rm-2`).
+
+
+.. fig:: fig:gc-rc-rm-1
+
+   Eliminación de la referencia ``r0`` :math:`\to` ``h1`` (parte 1).
+
+   .. subfig::
+
+      Se ejecuta ``update(r0, null)``.
+
+      .. digraph:: g3_1
+
+         margin = 0;
+         ratio  = fill;
+         size   = "3.0,3.8";
+         edge [ color = gray40 ];
+         node [
+            shape     = record,
+            width     = 0,
+            height    = 0,
+            style     = filled,
+            fillcolor = gray25,
+            fontcolor = white
+         ];
+
+         subgraph cluster_all {
+
+            root [
+               label     = "root\nset|<r0> r0\n*|<r1> r1",
+               style     = filled,
+               fillcolor = gray96,
+               fontcolor = black,
+            ];
+
+            h1 [ label = "h1\n1|<l> left|<r> right" ];
+            h2 [ label = "h2\n2|<l> left|<r> right" ];
+            h3 [ label = "h3\n2|<l> left|<r> right" ];
+            h4 [ label = "h4\n1|<l> left|<r> right" ];
+            h5 [ label = "h5\n1|<l> left|<r> right" ];
+            h6 [ label = "h6\n1|<l> left|<r> right" ];
+
+            root:r0 -> h1 [ style = bold, color = black ];
+            root:r1 -> h3;
+            h1:l -> h2;
+            h1:r -> h3;
+            h2:l -> h4;
+            h2:r -> h5;
+            h3:l -> h2;
+            h3:r -> h6;
+
+         }
+
+   .. subfig::
+
+      Se decrementa el contador de ``h1`` y éste queda en 0 (indicando
+      que es basura). Esto desencadena la eliminación de las referencias
+      ``h1.left`` y ``h1.right``.
+
+      .. digraph:: g3_2
+
+         margin = 0;
+         ratio  = fill;
+         size   = "3.0,3.8";
+         edge [ color = gray40 ];
+         node [
+            shape     = record,
+            width     = 0,
+            height    = 0,
+            style     = filled,
+            fillcolor = gray25,
+            fontcolor = white
+         ];
+
+         subgraph cluster_all {
+
+            root [
+               label     = "root\nset|<r0> r0\n*|<r1> r1",
+               style     = filled,
+               fillcolor = gray96,
+               fontcolor = black,
+            ];
+
+            subgraph marked {
+               node [ fillcolor = white, fontcolor = black ];
+               h1;
+            };
+
+            h1 [ label = "h1\n0|<l> left|<r> right" ];
+            h2 [ label = "h2\n2|<l> left|<r> right" ];
+            h3 [ label = "h3\n2|<l> left|<r> right" ];
+            h4 [ label = "h4\n1|<l> left|<r> right" ];
+            h5 [ label = "h5\n1|<l> left|<r> right" ];
+            h6 [ label = "h6\n1|<l> left|<r> right" ];
+
+            root:r0 -> h1 [ style = invis ];
+            root:r1 -> h3;
+            h1:l -> h2 [ style = bold, color = black ];
+            h1:r -> h3;
+            h2:l -> h4;
+            h2:r -> h5;
+            h3:l -> h2;
+            h3:r -> h6;
+
+         }
+
+.. fig:: fig:gc-rc-rm-2
+
+   Eliminación de la referencia ``r0`` :math:`\to` ``h1`` (parte 2).
+
+   .. subfig::
+
+      Se decrementa el contador de ``h2`` pero no queda en 0, por lo
+      tanto no es necesario descender a sus hijas; se continúa con
+      ``h3``.
+
+      .. digraph:: g3_3
+
+         margin = 0;
+         ratio  = fill;
+         size   = "3.0,3.8";
+         edge [ color = gray40 ];
+         node [
+            shape     = record,
+            width     = 0,
+            height    = 0,
+            style     = filled,
+            fillcolor = gray25,
+            fontcolor = white
+         ];
+
+         subgraph cluster_all {
+
+            root [
+               label     = "root\nset|<r0> r0\n*|<r1> r1",
+               style     = filled,
+               fillcolor = gray96,
+               fontcolor = black,
+            ];
+
+            subgraph marked {
+               node [ fillcolor = white, fontcolor = black ];
+               h1;
+            };
+
+            h1 [ label = "h1\n0|<l> left|<r> right" ];
+            h2 [ label = "h2\n1|<l> left|<r> right" ];
+            h3 [ label = "h3\n2|<l> left|<r> right" ];
+            h4 [ label = "h4\n1|<l> left|<r> right" ];
+            h5 [ label = "h5\n1|<l> left|<r> right" ];
+            h6 [ label = "h6\n1|<l> left|<r> right" ];
+
+            root:r0 -> h1 [ style = invis ];
+            root:r1 -> h3;
+            h1:l -> h2 [ style = invis ];
+            h1:r -> h3 [ style = bold, color = black ];
+            h2:l -> h4;
+            h2:r -> h5;
+            h3:l -> h2;
+            h3:r -> h6;
+
+         }
+
+   .. subfig::
+
+      El contador de ``h3`` tampoco queda en 0; no hay necesidad de
+      descender a sus hijas y finaliza el proceso.
+
+      .. digraph:: g3_4
+
+         margin = 0;
+         ratio  = fill;
+         size   = "3.0,3.8";
+         edge [ color = gray40 ];
+         node [
+            shape     = record,
+            width     = 0,
+            height    = 0,
+            style     = filled,
+            fillcolor = gray25,
+            fontcolor = white
+         ];
+
+         subgraph cluster_all {
+
+            root [
+               label     = "root\nset|<r0> r0|<r1> r1",
+               style     = filled,
+               fillcolor = gray96,
+               fontcolor = black,
+            ];
+
+            subgraph marked {
+               node [ fillcolor = white, fontcolor = black ];
+               h1;
+            };
+
+            h1 [ label = "h1\n0|<l> left|<r> right" ];
+            h2 [ label = "h2\n1|<l> left|<r> right" ];
+            h3 [ label = "h3\n1|<l> left|<r> right" ];
+            h4 [ label = "h4\n1|<l> left|<r> right" ];
+            h5 [ label = "h5\n1|<l> left|<r> right" ];
+            h6 [ label = "h6\n1|<l> left|<r> right" ];
+
+            root:r0 -> h1 [ style = invis ];
+            root:r1 -> h3;
+            h1:l -> h2 [ style = invis ];
+            h1:r -> h3 [ style = invis ];
+            h2:l -> h4;
+            h2:r -> h5;
+            h3:l -> h2;
+            h3:r -> h6;
+
+         }
+
+
+Luego se cambia una referencia (en vez de eliminarse) realizándose la
+operación ``update(h3.left, h5)``. Para esto primero se incrementa el
+contador de referencias de ``h5`` para evitar confundirlo accidentalmente
+con *basura* (figura :vref:`fig:gc-rc-up-1`). Luego se procede
+a decrementar el contador de ``h2`` que queda en 0 (transformándose en
+*basura*) y lo mismo pasa cuando se desciende a ``h4`` (figura
+:vref:`fig:gc-rc-up-2`). Finalmente se decrementa el contador de ``h5``
+pero como esta celda va a ser apuntada por ``h3`` (por la operación que
+está ejecutándose) sobrevive y permanece en el *live set*.  Finalmente se
+termina de actualizar la referencia ``h3.left`` para que apunte a ``h5``
+(figura :vref:`fig:gc-rc-up-3`).
+
+
+.. fig:: fig:gc-rc-up-1
+
+   TODO Eliminación de la referencia ``r0`` :math:`\to` ``h1`` (parte 1).
+
+   .. subfig::
+
+      TODO
+
+      .. digraph:: g4_1
+
+         margin = 0;
+         ratio  = fill;
+         size   = "3.0,3.8";
+         edge [ color = gray40 ];
+         node [
+            shape     = record,
+            width     = 0,
+            height    = 0,
+            style     = filled,
+            fillcolor = gray25,
+            fontcolor = white
+         ];
+
+         subgraph cluster_all {
+
+            root [
+               label     = "root\nset|<r0> r0|<r1> r1",
+               style     = filled,
+               fillcolor = gray96,
+               fontcolor = black,
+            ];
+
+            subgraph marked {
+               node [ fillcolor = white, fontcolor = black ];
+               h1;
+            };
+
+            h1 [ label = "h1\n0|<l> left|<r> right" ];
+            h2 [ label = "h2\n1|<l> left|<r> right" ];
+            h3 [ label = "h3\n1|<l> left\n*|<r> right" ];
+            h4 [ label = "h4\n1|<l> left|<r> right" ];
+            h5 [ label = "h5\n1|<l> left|<r> right" ];
+            h6 [ label = "h6\n1|<l> left|<r> right" ];
+
+            root:r0 -> h1 [ style = invis ];
+            h1:l -> h2 [ style = invis ];
+            h1:r -> h3 [ style = invis ];
+            root:r1 -> h3;
+            h2:l -> h4;
+            h2:r -> h5;
+            h3:l -> h2 [ style = bold, color = black ];
+            h3:r -> h6;
+
+         }
+
+   .. subfig::
+
+      TODO
+
+      .. digraph:: g4_2
+
+         margin = 0;
+         ratio  = fill;
+         size   = "3.0,3.8";
+         edge [ color = gray40 ];
+         node [
+            shape     = record,
+            width     = 0,
+            height    = 0,
+            style     = filled,
+            fillcolor = gray25,
+            fontcolor = white
+         ];
+
+         subgraph cluster_all {
+
+            root [
+               label     = "root\nset|<r0> r0|<r1> r1",
+               style     = filled,
+               fillcolor = gray96,
+               fontcolor = black,
+            ];
+
+            subgraph marked {
+               node [ fillcolor = white, fontcolor = black ];
+               h1;
+            };
+
+            h1 [ label = "h1\n0|<l> left|<r> right" ];
+            h2 [ label = "h2\n1|<l> left|<r> right" ];
+            h3 [ label = "h3\n1|<l> left\n*|<r> right" ];
+            h4 [ label = "h4\n1|<l> left|<r> right" ];
+            h5 [ label = "h5\n2|<l> left|<r> right" ];
+            h6 [ label = "h6\n1|<l> left|<r> right" ];
+
+            root:r0 -> h1 [ style = invis ];
+            h1:l -> h2 [ style = invis ];
+            h1:r -> h3 [ style = invis ];
+            root:r1 -> h3;
+            h2:l -> h4;
+            h2:r -> h5;
+            h3:l -> h2 [ style = bold, color = black ];
+            h3:l -> h5 [ style = dotted, color = black ];
+            h3:r -> h6;
+
+         }
+
+.. fig:: fig:gc-rc-up-2
+
+   TODO Eliminación de la referencia ``r0`` :math:`\to` ``h1`` (parte 2).
+
+   .. subfig::
+
+      TODO
+
+      .. digraph:: g4_3
+
+         margin = 0;
+         ratio  = fill;
+         size   = "3.0,3.8";
+         edge [ color = gray40 ];
+         node [
+            shape     = record,
+            width     = 0,
+            height    = 0,
+            style     = filled,
+            fillcolor = gray25,
+            fontcolor = white
+         ];
+
+         subgraph cluster_all {
+
+            root [
+               label     = "root\nset|<r0> r0|<r1> r1",
+               style     = filled,
+               fillcolor = gray96,
+               fontcolor = black,
+            ];
+
+            subgraph marked {
+               node [ fillcolor = white, fontcolor = black ];
+               h1; h2;
+            };
+
+            h1 [ label = "h1\n0|<l> left|<r> right" ];
+            h2 [ label = "h2\n0|<l> left|<r> right" ];
+            h3 [ label = "h3\n1|<l> left\n*|<r> right" ];
+            h4 [ label = "h4\n1|<l> left|<r> right" ];
+            h5 [ label = "h5\n2|<l> left|<r> right" ];
+            h6 [ label = "h6\n1|<l> left|<r> right" ];
+
+            root:r0 -> h1 [ style = invis ];
+            h1:l -> h2 [ style = invis ];
+            h1:r -> h3 [ style = invis ];
+            root:r1 -> h3;
+            h2:l -> h4 [ style = bold, color = black ];
+            h2:r -> h5;
+            h3:l -> h2 [ style = invis ];
+            h3:l -> h5 [ style = dotted, color = black ];
+            h3:r -> h6;
+
+         }
+
+   .. subfig::
+
+      TODO
+
+      .. digraph:: g4_4
+
+         margin = 0;
+         ratio  = fill;
+         size   = "3.0,3.8";
+         edge [ color = gray40 ];
+         node [
+            shape     = record,
+            width     = 0,
+            height    = 0,
+            style     = filled,
+            fillcolor = gray25,
+            fontcolor = white
+         ];
+
+         subgraph cluster_all {
+
+            root [
+               label     = "root\nset|<r0> r0|<r1> r1",
+               style     = filled,
+               fillcolor = gray96,
+               fontcolor = black,
+            ];
+
+            subgraph marked {
+               node [ fillcolor = white, fontcolor = black ];
+               h1; h2; h4;
+            };
+
+            h1 [ label = "h1\n0|<l> left|<r> right" ];
+            h2 [ label = "h2\n0|<l> left|<r> right" ];
+            h3 [ label = "h3\n1|<l> left\n*|<r> right" ];
+            h4 [ label = "h4\n0|<l> left|<r> right" ];
+            h5 [ label = "h5\n2|<l> left|<r> right" ];
+            h6 [ label = "h6\n1|<l> left|<r> right" ];
+
+            root:r0 -> h1 [ style = invis ];
+            h1:l -> h2 [ style = invis ];
+            h1:r -> h3 [ style = invis ];
+            root:r1 -> h3;
+            h2:l -> h4 [ style = invis ];
+            h2:r -> h5 [ style = bold, color = black ];
+            h3:l -> h2 [ style = invis ];
+            h3:l -> h5 [ style = dotted, color = black ];
+            h3:r -> h6;
+
+         }
+
+.. fig:: fig:gc-rc-up-3
+
+   TODO Eliminación de la referencia ``r0`` :math:`\to` ``h1`` (parte 3).
+
+   .. subfig::
+
+      TODO
+
+      .. digraph:: g4_5
+
+         margin = 0;
+         ratio  = fill;
+         size   = "3.0,3.8";
+         edge [ color = gray40 ];
+         node [
+            shape     = record,
+            width     = 0,
+            height    = 0,
+            style     = filled,
+            fillcolor = gray25,
+            fontcolor = white
+         ];
+
+         subgraph cluster_all {
+
+            root [
+               label     = "root\nset|<r0> r0|<r1> r1",
+               style     = filled,
+               fillcolor = gray96,
+               fontcolor = black,
+            ];
+
+            subgraph marked {
+               node [ fillcolor = white, fontcolor = black ];
+               h1; h2; h4;
+            };
+
+            h1 [ label = "h1\n0|<l> left|<r> right" ];
+            h2 [ label = "h2\n0|<l> left|<r> right" ];
+            h3 [ label = "h3\n1|<l> left\n*|<r> right" ];
+            h4 [ label = "h4\n0|<l> left|<r> right" ];
+            h5 [ label = "h5\n1|<l> left|<r> right" ];
+            h6 [ label = "h6\n1|<l> left|<r> right" ];
+
+            root:r0 -> h1 [ style = invis ];
+            h1:l -> h2 [ style = invis ];
+            h1:r -> h3 [ style = invis ];
+            root:r1 -> h3;
+            h2:l -> h4 [ style = invis ];
+            h2:r -> h5 [ style = invis ];
+            h3:l -> h5 [ style = bold, color = black ];
+            h3:l -> h2 [ style = invis ];
+            h3:r -> h6;
+
+         }
+
+   .. subfig::
+
+      TODO
+
+      .. digraph:: g4_6
+
+         margin = 0;
+         ratio  = fill;
+         size   = "3.0,3.8";
+         edge [ color = gray40 ];
+         node [
+            shape     = record,
+            width     = 0,
+            height    = 0,
+            style     = filled,
+            fillcolor = gray25,
+            fontcolor = white
+         ];
+
+         subgraph cluster_all {
+
+            root [
+               label     = "root\nset|<r0> r0|<r1> r1",
+               style     = filled,
+               fillcolor = gray96,
+               fontcolor = black,
+            ];
+
+            subgraph marked {
+               node [ fillcolor = white, fontcolor = black ];
+               h1; h2; h4;
+            };
+
+            h1 [ label = "h1\n0|<l> left|<r> right" ];
+            h1 [ label = "h1\n0|<l> left|<r> right" ];
+            h2 [ label = "h2\n0|<l> left|<r> right" ];
+            h3 [ label = "h3\n1|<l> left|<r> right" ];
+            h4 [ label = "h4\n0|<l> left|<r> right" ];
+            h5 [ label = "h5\n1|<l> left|<r> right" ];
+            h6 [ label = "h6\n1|<l> left|<r> right" ];
+
+            root:r0 -> h1 [ style = invis ];
+            h1:l -> h2 [ style = invis ];
+            h1:r -> h3 [ style = invis ];
+            root:r1 -> h3;
+            h2:l -> h4 [ style = invis ];
+            h2:r -> h5 [ style = invis ];
+            h3:l -> h5;
+            h3:l -> h2 [ style = invis ];
+            h3:r -> h6;
+
+         }
+

 
 .. _ref_gc_cycles:
 
 
 .. _ref_gc_cycles: