On Wed, Feb 11, 2015 at 3:15 AM, Marc Mezzarobba <m...@mezzarobba.net> wrote: > Volker Braun wrote: >> My advice would be to implement the parent in Python and benchnmark >> it. If you are doing something in _element_constructor_ that would >> benefit greatly by Cython then you can just move that part to Cython. > > Apparently my question was unclear. Of course, it is good advice as a > general rule decide based on profiling results. But: _assuming_ not only > that parts of what _element_constructor_ does benefit from Cython, but > also that the cost of issuing a Python method call when constructing > elements is significant, what is the best approach to deal with it?
Let MyParent be defined in my_parent.py, and MyElement be defined in my_element.pyx. Say your parent doesn't override __call__ (which it shouldn't), in which case you'll inherit the Cythonized Parent.__call__. When you write MyParent(x, *args, **kwds) this will finds/creates the appropriate morphism parent(x) -> MyParent. By default, this invokes MyParent._element_constructor_(x, *args, **kwds) as fast as possible (it's actually cached, so there's not even a dict lookup there). Now MyParent._element_constructor_ need not be defined in my_parent.py, in fact it's often MyElement's constructor. > Or, to put it differently: why are so many parents Cython classes if > there are no benefits? Some Parent have methods and/or data that is best implemented in Cython. Others are like that for historical reasons and/or incomplete understanding. As Volker said On Wed, Feb 11, 2015 at 7:07 AM, Volker Braun <vbraun.n...@gmail.com> wrote: > Some of the basic parent/elements in Sage are extremely optimized and not a > good model for getting started with your own structure. I would go further and say they're not even all good models for how to make things fast; a lot of early parents pre-date Cython itself, let alone the coercion model, etc. -- 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 sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
