📝 add back note about graphviz

docs/source/library/Visualization.rst

@@ -15,6 +15,13 @@ The recommended way to visualize search graphs of a mapping process is via a :cl
 .. note::
     :meth:`SearchVisualizer.visualize_search_graph` returns an IPython display object and therefore requires to be executed in a jupyter notebook or jupyter lab environment.
 
+.. note::
+    Automatic layouting of architecture or search nodes requires `Graphviz <https://graphviz.org/>`_ to be installed (except for the layouting method :code:`walker`). If Graphviz is called without it being installed, it will ensue in an error such as:
+
+    :code:`FileNotFoundError: [Errno 2] "sfdp" not found in path.`
+
+    Consequently, the only way to use :meth:`SearchVisualizer.visualize_search_graph` without Graphviz is by passing explicit architecture node positions or hiding the architecture graph by passing :code:`show_layout=None`.
+
 .. autoclass:: SearchVisualizer
     :special-members: __init__
     :members: