Describing your Simulated Platform
##################################
In SimGrid, platforms are usually described in XML. This formalism has
some drawbacks, but using a specific format ensures that the platform
is not mixed with the tested application. This separation of concern
:ref:`is a must ` for your Modeling and Simulation (M&S)
work. When XML is too limiting, you may describe your platforms using
the :ref:`lua bindings ` (it is not yet possible to do so in
python or directly in C++).
Since we know that writing platform description files is not trivial,
we included :ref:`many examples ` in the archive. This
documentation also contains some :ref:`hints and howtos `, as well
as the full :ref:`XML reference guide `.
Any simulated platform must contain **basic elements**, such as hosts,
links, storages, etc. SimGrid gives you a great liberty when defining
**routing of your platform**, ie the path taken between each pair of
hosts. Finally, you may also describe an **experimental scenario**,
with qualitative changes (e.g., bandwidth changes representing an
external load) and qualitative changes (representing how some elements
fail and restart over time).
Defining Basic Elements
***********************
There is not much to say about the definition of basic elements. Just
use the appropriate tags: :ref:`pf_tag_host`, :ref:`pf_tag_link` and
:ref:`pf_tag_storage`.
Defining a Routing
******************
Performance Profiles and Churn
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.. LocalWords: SimGrid