Incidentally, if you and Burcin think this is worthwhile in general,
please feel free to make a Trac ticket so that it's easier for others
to test these ideas out. Thank you - looking forward to it!
- kcrisman
On Jul 29, 11:43 am, Steven Pollack <stevenlawrencepoll...@gmail.com>
wrote:
> Thanks for the explanation! I haven't had a chance to try installing
> the patch (I got caught up taking care of some other side-projects),
> however I can't thank you enough for the help.
>
> I now have a new question (@Robert): if the Expression class wasn't
> made with subclassing in mind, how did the makers of sage envision
> users to build their own classes (while still utilizing expressions)?
>
> I'm new to OOP, but the impression I'm (now) under is that without
> Burcin's patch, we have to do something like:
>
> class newObject():
> def __init___(self, expression, *variables, **attributes):
> [var('{0}'.format(variable)) for variable in
> variables]
> self.exp = expression
> for options in attributes.items():
> self.attr[option] = attributes(option)
> ?
>
> Thanks,
>
> Steven
>
> On Jul 26, 3:15 pm, Burcin Erocal <bur...@erocal.org> wrote:
>
>
>
> > On Mon, 25 Jul 2011 08:03:04 -0700 (PDT)
>
> > Steven Pollack <stevenlawrencepoll...@gmail.com> wrote:
> > > Is the syntax for this class
>
> > > t = new_exp(SR, symbolic_expression)?
>
> > > So that sage: t returns symbolic_expression?
>
> > t is an instance of new_exp, which inherits from Expression. The value
> > of the internal GiNaC object stored in both is determined by the second
> > argument.
>
> > You could define other member functions or store attributes in your
> > class. Though you need to take care what happens to the attributes
> > when you do any arithmetic.
>
> > sage: class new_exp(Expression):
> > def __init__(self, parent, value, attribute):
> > self.attr = attribute
> > super(self.__class__, self).__init__(parent, value)
> > ....:
> > sage: t = new_exp(SR, x, 2)
> > sage: t
> > x
> > sage: t.attr
> > 2
> > sage: t.new_method(5)
> > x - 5
> > sage: u = t+t
> > sage: u.new_method(5)
> > 2*x - 5
> > sage: u.attr
> > <snip>
> > AttributeError: 'new_exp' object has no attribute 'attr'
> > sage: type(u)
> > <class '__main__.new_exp'>
> > sage: u
> > 2*x
> > sage: v = u/2
> > sage: v.new_method(5)
> > x - 5
> > sage: v.attr
> > <snip>
> > AttributeError: 'new_exp' object has no attribute 'attr'
>
> > > Second, I'm not entirely sure I understand how this patch was made,
> > > let alone how to install it. I skimmed over
> > >http://www.sagemath.org/doc/developer/patching_spkgs.htmland
> > >http://www.sagemath.org/doc/developer/producing_spkgs.html#chapter-spkg
> > > but found the whole thing to be a bit over my head (I'm a newbie,
> > > sorry).
>
> > > Is there a series of instructions you could provide me for the
> > > installation of your patch? I'm sure you're very busy, so I really do
> > > appreciate the effort.
>
> > You need to look at a different section of the guide:
>
> >http://sagemath.org/doc/developer/walk_through.html
>
> > Here is a quick summary:
>
> > - Go to your SAGE_ROOT, the base directory of your sage installation
> > - Go to the directory with the sage library sources
> > cd devel/sage
> > - import the patch into a patch queue
> > hg qimport <URL_of_patch>
> > - apply the patch
> > hg qpush
> > - go back to SAGE_ROOT
> > cd ../..
> > - build the library with changes
> > ./sage -b
> > - start Sage and enjoy
> > ./sage
>
> > Cheers,
> > Burcin
--
To post to this group, send email to sage-support@googlegroups.com
To unsubscribe from this group, send email to
sage-support+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/sage-support
URL: http://www.sagemath.org
