Re: Python plugin for Gnucap

henrik johansson wrote:
> Hi all,
>
> My name is Henrik Johansson and I have been lurking on this list for
> quite a long time. I am an analog/RF IC designer by trade
> and I normally work with commercial simulators like Spectre and Eldo.
>
> I think Gnucap is really the best open-source simulator out there but
> unfortunately the open-source EDA world lacks a post-processing
> framework like the Ocean library in Cadence and a nice
> waveform-viewer. According to me this should be written in Python.
>
> I have seen that there have been some fruitless attempts to write a
> python module for gnucap but I don't know how far they came.  Anyway,
> I gave it a shot myself and wrote a plugin for gnucap which registers
> a new "python" command that starts a Python interpreter and
> runs a python script where the filename is given as an argument. I
> have already talked to Al about it and he urged me to write to the
> list instead so here it comes!
>
> In order to do something interesting in the embedded Python
> interpreter I also wrote a Swig wrapper for some of the gnucap
> classes. Currently this allows you to extend the CMD class in python
> and register new commands written in Python. As an example I wrote a
> new plot function that plots a stored waveform using matplotlib.
>
> I also tried a different approach, to compile gnucap as a shared
> library and write a gnucap extension for Python that calls that
> basically replaces the gnucap command main function. This way could be
> useful if gnucap is called from a high level simulation environment.
> The modifiaction is only in the autoconf/automake files so no code is
> changed. Along with the shared library, the header files are also
> installed in $PREFIX/include/gnucap which makes it possible to compile
> plugins freely without relying on the gnucap source tree. The gnucap
> command now contains only the main function and is dependent on the
> share library libgnucap.so.
>
> The modified gnucap source tree can be found at
> http://github.com/henjo/gnucap.
>
> The python plugin is here:
> http://github.com/henjo/gnucap-python. You can download tar-balls of
> all github repos directly.
>
> I think this can also be used to implement new analyses like periodic
> steady state which can run as a Python defined command and run
> transients from gnucap. The performance penalty should be minimal.
>
> Best regards,
>
> Henrik Johansson
>
>   
Thanks for this, I am currently using python and gnucap together by 
running gnucap via a pipe, writing the results to a file and then 
plotting with matplotlib. I will be very interested to try your Python 
interface once I have more time.

Thanks,
Tom