On Apr 7, 2008, at 10:07 AM, Jason Grout wrote: > > In trying to unify the linear algebra syntax, I came across the > following behavior: > > > sage: a=matrix(2,range(4)) > sage: a.nrows() > 2 > sage: a._nrows > ---------------------------------------------------------------------- > ----- > <type 'exceptions.AttributeError'> Traceback (most recent > call last) > > /home/grout/sage/devel/sage-main/sage/misc/<ipython console> in > <module>() > > <type 'exceptions.AttributeError'>: > 'sage.matrix.matrix_integer_dense.Matrix_integer_de' object has no > attribute '_nrows' > sage: a.__dict__ > ---------------------------------------------------------------------- > ----- > <type 'exceptions.AttributeError'> Traceback (most recent > call last) > > /home/grout/sage/devel/sage-main/sage/misc/<ipython console> in > <module>() > > <type 'exceptions.AttributeError'>: > 'sage.matrix.matrix_integer_dense.Matrix_integer_de' object has no > attribute '__dict__' > > > I noted that the nrows() function just returned self._nrows. So how > come I can't access _nrows? Does it have to do with Cython and > inheritance?
Yes, this is a Cython vs. Python issue. a._nrows is literally a c int in the object structure, not a member of a dictionary. In fact, Cython classes don't even have dictionaries. From Cython a._nrows is probably on the order of two or three magnitudes faster than a.nrows() We could declare _nrows and _ncols to be readonly, in which case a __getattr__ (or more technically a property accessor method) method would be created for them. - Robert --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
