On Mon, Mar 17, 2014 at 06:36:47PM -0400, Mark Shimozono wrote:
> I have been needing to define lots of morphisms using pure functions.
>
> Here's a simple example: try to give every free module an identity morphism
> in a way that passes pickling.
>
> {{{
>
> class ModulesWithBasis(Category_over_base_ring):
> ...
> class ParentMethods:
> ...
> def _identity_map(self):
> def the_id(x):
> return x
> import __main__; __main__.the_id = the_id
> return SetMorphism(Hom(self,self,self.category()),the_id)
>
> }}}
>
> This isn't going to work if the method is called multiple times
> because the global reference will get overwritten.
Oh, sorry for the confusion. If the function is already defined in
some Python module (but not within a function another), it's right
away picklable, so there is nothing to do. The example above would
become:
{{{
def id(x): return x
class ...
def _identity_map(self):
return SetMorphism(Hom(self,self,self.category()),id)
}}}
This __main__ trick is only for when you define python
functions "interactively" (e.g. in doctests), and you want to fake
them being picklable for TestSuite's pickling tests.
Cheers,
Nicolas
--
Nicolas M. Thiéry "Isil" <[email protected]>
http://Nicolas.Thiery.name/
--
You received this message because you are subscribed to the Google Groups
"sage-devel" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/sage-devel.
For more options, visit https://groups.google.com/d/optout.
