[Numpy-discussion] ufuncs on user-defined types in numarray

Todd Miller jmiller at stsci.edu
Mon Dec 20 11:34:07 CST 2004


Hi Gary and Konrad,

I filed a Numarray Enhancement Request on Source Forge for this feature.
It's not clear if, when, or how it will be implemented but it won't be
completely forgotten either.

Regards,
Todd

On Sun, 2004-12-19 at 16:37 +1000, Gary Ruben wrote:
> Thanks Konrad,
> I didn't realise this was possible. I should use it on my ErrorVal module <http://users.bigpond.net.au/gazzar/python.html>. Last time I tried (quite a while ago), numarray's object array support wasn't up to allowing me to port ErrorVal from Numeric. I don't think it matters since I don't know of anyone, besides me, who has tried using my module :-( but I thought I'd mention it for Todd's benefit since I'm one who could benefit from implementing it in numarray.
> Gary R.
> 
> ----- Original Message -----
> From: "Todd Miller" <jmiller at stsci.edu>
> To: konrad.hinsen at laposte.net
> Subject: Re: [Numpy-discussion] ufuncs on user-defined types in numarray
> Date: 17 Dec 2004 10:09:51 -0500
> 
> > 
> > On Fri, 2004-12-17 at 08:31, konrad.hinsen at laposte.net wrote:
> > > I am working on making ScientificPython 
> > > (http://dirac.cnrs-orleans.fr/ScientificPython/) compatible with 
> > > numarray. One problem I stumbled across is that one feature of 
> > > Numeric seems to be absent from numarray: the possibility to call 
> > > ufuncs with arguments of non-numeric types, leading to a 
> > > corresponding method call.
> > >
> > > As an illustration, the following example works fine with 
> > > Numeric, but crashes with numarray:
> > >
> > > from Numeric import sqrt
> > > #from numarray import sqrt
> > >
> > > class DummyValue:
> > >
> > >      def __init__(self, string):
> > >          self.string = string
> > >
> > >      def __str__(self):
> > >          return self.string
> > >
> > >      def sqrt(self):
> > >          return DummyValue('sqrt(%s)' % self.string)
> > >
> > > x = DummyValue('x')
> > > print sqrt(x)
> > >
> > >
> > > Is this a bug or a feature?
> > 
> > It's a missing feature.
> > 
> > > Is there another way to make ufuncs work with user-defined classes and types?
> > 
> > Not that I know of.  How critical a feature is it?  Do you have a work around?
> > 
> > numarray ufunc handling is in flux as I'm adding numarray support to
> > scipy.  At some point,  there's going to be a major ufunc consolidation,
> > and perhaps I can add this additional feature then.
> > 
> > Regards,
> > Todd
> > 
> > 
> > 
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