.. include:: /defs.txt

LISO input file parsing
=======================

Known incompatibilities
-----------------------

Duplicate component and node names
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In LISO, nodes and components may share the same name, and the user is warned that this may lead to
confusion. In |Zero|, nodes and components cannot share the same name.

Outputs
~~~~~~~

|Zero| does not support the ``deg+`` or ``deg-`` output coordinates. Please use ``deg`` instead. It
also throws an error when a LISO script's ``ioutput`` or ``uoutput`` commands contain only a phase
coordinate, e.g.:

.. code-block:: text

    uoutput nout:deg

Such outputs could in principle be handled by |Zero|, but it would add complexity to the
:class:`Solution` and :class:`Series` classes that is not worth the effort given how rare this type
of output is. In order to use such scripts with |Zero|, simply add a magnitude unit, e.g.

.. code-block:: text

    uoutput nout:db:deg

Root mode
~~~~~~~~~

|Zero| does not support LISO's root mode, meaning that the fitting tools provided in LISO for
responses and noise spectra are not replicated. It is suggested to instead use |Zero| with a Python
optimisation library such as `scipy.optimize
<https://docs.scipy.org/doc/scipy/reference/optimize.html>`_. Note that it is very important for
circuit responses and noise fitting to use a well-suited optimiser, particularly one that can fit in
log space. LISO's fitting library performs very well for this purpose.

Commands
~~~~~~~~

The following commands are not yet supported:

- :code:`factor` (input multiplicative factor)
- :code:`zin` (input impedance)
- :code:`opdiff` (plot op-amp input differential voltage)
- :code:`margin` (compute op-amp phase margin; replaced :code:`opstab` in LISO v1.78)
- :code:`sens` (print table of component sensitivities)

Here are some commands which will probably not be supported:

- other `max` or `min` based commands, e.g. :code:`maxinput`
- :code:`eagle` (produce EAGLE file)
- :code:`gnuterm`
- component :code:`C0805` (0805 capacitor with parasitic properties; not implemented in
  favour of grouping components together with macros)

Op-amp library
~~~~~~~~~~~~~~

LISO's op-amp library format is not supported, but the full LISO library is bundled in |Zero|'s
native format. Among other features, |Zero|'s library improves on that of LISO's by allowing an
``alias`` setting where you can specify other op-amps with the same properties.

The parameters ``un``, ``uc`` ``in`` and ``ic`` have been renamed ``vnoise``, ``vcorner``,
``inoise`` and ``icorner``, respectively.

Submissions of op-amp parameters to |Zero|'s library are strongly encouraged
(see :ref:`contributing/index:Op-amp library additions`).

LISO Perl commands
~~~~~~~~~~~~~~~~~~

Commands used for running LISO in a loop with :code:`pfil` are not supported. Instead you can use
|Zero| as part of a Python script to run either LISO or native |Zero| simulations in a loop.

Differences in behaviour
------------------------

Command order
~~~~~~~~~~~~~

In LISO, the output must be specified *after* the components. In |Zero|, order is irrelevant.

`Noisy` command
~~~~~~~~~~~~~~~

.. code-block:: text

    noisy all|allr|allop|noise-source [all|allr|allop|noise-source] ...

The LISO manual states in section 7.3 regarding the noise sources used to calculate the :code:`sum`
output:

    Note also that all noise sources that are included in the `noise` instruction, i.e. those that
    are plotted individually, are automatically considered "noisy", i.e. they are always included in
    the sum.

In LISO, if the :code:`sum` output is present but there is no :code:`noisy` command, the following
error is displayed:

.. code-block:: text

    *** Error: No noisy components! (Try 'noisy all')

In |Zero|, the :code:`noisy` command does not need to be present as by default, even in LISO, the
noise sources that contribute to the :code:`sum` output always includes those specified in the
output itself. The :code:`noisy` command is available merely to add additional noise sources to the
:code:`sum` that are not explicitly plotted.

As the lack of presence of a :code:`noisy` command in this case does not yield *different* results
to LISO, only an error in one case and a reasonable output in the other, this behaviour is not
considered a bug.

String lengths
~~~~~~~~~~~~~~

LISO has a limit of 16 for most strings (component names, op-amp types, node names, etc.). In |Zero|
the limit is effectively arbitrary.

.. hint::
    In the case of *mutual inductance* commands, the name is entirely ignored. This is used in LISO
    only for fitting routines, which are not part of |Zero|.