Go-Smart Simulation Architecture XML Format (GSSA-XML)
======================================================

**Note**: this is distinct from
`GSSF-XML <https://go-smart.github.io/goosefoot/xml/>`__.

GSSA-XML is documented as an XML Schema in the ``schema`` directory of
the source tree. However, to provide a human-readable resource, it is
described also here:

.. code-block:: xml

    <simulationDefinition>
        <transferrer class="(http|tmp)">
            <!-- See Transferrers documentation -->
        </transferrer>
        <algorithms>
            <!-- See Algorithms documentation -->
        </algorithms>
        <parameters>
            <!-- See Parameters#concrete-parameters documentation -->
        </parameters>
        <numericalModel>
            <needles>
                <needle index="NIX" class="NCL" file="NFILE">
                    <parameters>
                        <!-- See Parameters#concrete-parameters documentation -->
                    </parameters>
                </needle>
                ...
            </needles>
            <regions>
                <region id="RID" name="RNAME" format="RFORMAT:(zone|surface|both)"
                    input="RINPUT" groups="RGROUPS" />
                ...
            </regions>
            <definition name="DFAMILY" file="[ DFILE ]">
                <!-- Family-specific content (see documentation for each family) -->
            </definition>
        </numericalModel>
    </simulationDefinition>


The needle index, ``NIX``, indicates the name by which this needle
should be referred to. They should be integers, ordering the needles
contiguously. The class, ``NCL``, identifies how a needle should be
incorporated into the simulation and should either be ``solid-boundary``
or ``boundary``. The exact needle definition is supplied by ``NFILE``,
which should be of the form ``library:LIBRARYTYPE`` or
``file:INPUTFILENAME.stl``. Within each needle node is another list of
needle-specific parameters.

Each region should have an ``RID`` that uniquely refers to them within
the simulation. The ``RNAME`` is a context-providing name that may be
used, such as ``organ`` or ``tumour``. A simple way to generate IDs is
to add an ordinal index to the name, e.g., ``tumour-1``. The ``RFORMAT``
indicates how the region should be treated, as a zone, surface or both
(volumetric subdomain, boundary, or embedded boundary). The ``RINPUT``
is the filename of the STL or VTP input file defining the surface. The
collection of region groups of which this region is a member should be
specified in the ``RGROUPS`` field, joined by "``;``\ ".

The definition ``DFAMILY`` selects the family that should handle the
definition. Note that it may be provided as a TAR.GZ (allowing, for
instance, Python modules) using the ``DFILE`` attribute, but is
otherwise the body of the ``definition`` tag itself.