On Fri, Nov 23, 2012 at 06:53:56PM -0800, Travis Scrimshaw wrote:
> Hey everyone,
> I just had an idea, and maybe this is more wishful thinking, but I feel
> like we should be able to pass a poset/lambda function(s)/class which
> contains comparison methods into a parent and have that be able to
> override the default ordering (similar to what C++ does in the STL).
> Something like this:
> sage: g = DiGraph([(0,1),(0,2)])
> sage: p = Poset(g)
> sage: G = IntegerRingMod(3, ordering=p)
> sage: G(0) < G(1)
> True
> sage: G(0) < G(2)
> True
> sage: G(1) < G(2)
> False
Well, maybe not that much of a wishful thinking actually!
Define this category:
class Blahs(Category):
def super_categories(self): return [Rings()]
class ParentMethods:
def blah(self): print "blah"
class ElementMethods:
def blih(self): print "blih"
def __lt__(self, other):
print "comparing!"
And create the ring in this category:
sage: G = IntegerModRing(3, category=Blahs())
sage: g = G.an_element()
Now you can do:
sage: G.blah()
blah
sage: g.blih()
blih
So in principle one could use that to provide comparison methods. Alas
this does not work completely, because there already is a comparison
method implemented in G which override that of the category:
sage: g < g
False
This also fails for partitions because they do not yet accept a
category parameter.
Cheers,
Nicolas
--
Nicolas M. Thiéry "Isil" <[email protected]>
http://Nicolas.Thiery.name/
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