[SciPy-user] about using python class in weave

[Jing (George) Cao]

I am now want to make SWIG and python work together, so I guess I met the
same problem.

Dave told me weave works fine with previous version of SWIG, and I also
found a directory named swig in WEAVE. Is there any document about what
you've done to make weave and previous SWIG works together and where can
I find it?

Thank you.

Jing

On Mon, 23 Sep 2002, eric jones wrote:

> Instance conversion isn't supported in the released version, but the CVS
> version handles it.  CVS also has limited support for working with
> attributes.  I'm in the process of augmenting SCXX for this sort of
> thing.  Support for calling methods (what you want) hasn't been added
> yet, but probably will appear within the next week or so.
>
> It's worth noting that, unless your Python class is a wrapper around a
> C++ class (using SWIG or boost or whatever), the performance is going to
> be lousy for this because it has to call back into Python.  It's
> actually worse than Python because of the overhead in the C++ classes
> used to represent Pyhon objects (perhaps this can be reduced).
>
> So, if your app needs to access the python class information within a
> computational loop, weave isn't going to help much.  However, if you can
> do something like:
>
> 	a = s.blah()
>       weave.inline("<do something time consuming with a>", ['a'])
>
> then you could get big wins.
>
> To get back to the same speed as Python (possibly even 10-100% faster
> actually), you can manipulate py_s instead of s.  py_s is a raw
> PyObject* and you can use the Python C API on this guy until your hearts
> content.
>
> The other option is to tackle the problem of writing type converters
> that are based on the boost library.  This library is a lot more complex
> than SCXX (which we use now), but it is also more powerful.  Something
> along the lines of what you want is probably likely using it.
>
> Regards,
> Eric
>
> > -----Original Message-----
> > From: scipy-user-admin at scipy.net [mailto:scipy-user-admin at scipy.net]
> On
> > Behalf Of Yijue Hou
> > Sent: Monday, September 23, 2002 1:51 PM
> > To: scipy-user at scipy.net
> > Subject: [SciPy-user] about using python class in weave
> >
> > weave.inline call use python integers directly,
> > but while I tried to use python classes, it doesn't work.
> >
> > suppose s is a python class,
> > my code:
> > weave.inline("s.blah();",['s'])
> >
> > it said it unable to convert to c++ types, so how to call python
> > classes in c function using  weave?
> >
> > Thanks
> >
> >
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