Global environment
==================

The global environment category contains mainly the context of a
simulation.

Global environments are HDF5 named groups children of ``/globalEnvironment``.

Example : ::

    data.h5
    `-- globalEnvironment
        |-- $ge1
        `-- $ge2

``data.h5:/globalEnvironment/$ge1`` and ``data.h5:/globalEnvironment/$ge1`` are
two global environment instances.


Time and frequency domains
--------------------------

If the simulation is in the frequency domain :
  ``/globalEnvironment/$globalEnvironment/frequency``
  contains the frequencies the computation will be performed at.

If the simulation is in the time domain :
  ``/globalEnvironment/$globalEnvironment/time`` is the
  definition of the simulation time.


``/globalEnvironment/$globalEnvironment/frequency``'s characteristics are :

* is a ``floatingType``
* ``physicalNature`` is ``frequency``
* ``unit`` is ``hertz``
  
``/globalEnvronment/$globalEnvironment/time``'s characteristics are :

* is a ``floatingType``
* ``physicalNature`` is ``time``
* ``unit`` is ``second``

.. note::

  If ``floatingType`` equals ``vector``, it is a float vector.


Examples ::

    data.h5
    `-- globalEnvironment
        `-- $ge1
            `-- time[floatingType=vector]

    data.h5
    `-- globalEnvironment
        `-- $ge1
            `-- frequency[@floatingType=logarithmListOfReal1
                          @first=10e3
                          @last=1e9
                          @numberOfValues=100]

.. note::

    For some temporal methods only the maximum time (tmax) is relevant, in fact, 
    the simulation is performed for time in the interval [0, tmax], 
    use an :ref:`interval` for this case :

::

    data.h5
    `-- globalEnvironment
        `-- $ge1
            `-- time[@floatingType=linearListOfReal2
                     @first=0
                     @last=1e-6]

Limit conditions
----------------

To gain a lot computation time, it is often necessary to model a system
with symmetries. The computation domain is then terminated with 
particular limit conditions.

Limit conditions can be :

* ``electricWall``. An electric wall is positioned as if a perfect
  electrical conductor was in the mesh.
* ``magneticWall``. A magnetic wall is positioned, the mirror effect is
  relative to the magnetic component.
  

Limit conditions are given by a ``/globalEnvironment/$ge/limitConditions`` HDF5
group.

For a cartesian coordinate system, the computation limits are located by six
string HDF5 attributes :

* ``xinf`` locates the inferior-x limit, the first plan orthogonal to the axis-x 
* ``xsup`` locates the superior-x limit 
* ``xinf`` locates the inferior-y limit 
* ``ysup`` locates the superior-y limit 
* ``zinf`` locates the inferior-z limit 
* ``zsup`` locates the superior-z limit 


example :

::

    data.h5
    `-- globalEnvironment
        `-- $ge1
            `-- limitConditons[@xinf=electricWall
                               @xsup=electricWall
                               @yinf=magneticWall] 

The example defined two electric symmetries and one magnetic symmetry as
in the sketch below :

.. image:: images/symmetry.png
  :width: 40%