On Nov 9, 2012, at 7:57 PM, Volker Braun wrote: > If you use the > > class MyParent(Parent) > Element = MyElement > > syntax then you have to import MyElement. So you shouldn't import MyParent in > your element code or you will create a cyclic import (=bad). > > Are you sure that you need to create new parents from the element? Your > element should only work with the parent that it is an element of. New > Parents are generally constructed by coercion, but the coercion code lives in > MyParent.
It's a bit more complicated than that… The setting is that if R is a (multivariate) polynomial ring, and I is an ideal of R, then checking that elements of the quotient R/I are regular requires working with a new polynomial ring R', which is essentially a copy of R with one more variable. So, sage.rings.QuotientRingElement needs to create instances of multivariate polynomial rings. > If all fails you can still do a method-level import. But its likely that you > should not. Sorry for not being very familiar with python, but could you elaborate a little? Thanks, Charles > > > > > On Friday, November 9, 2012 1:13:20 PM UTC-5, Charles Bouillaguet wrote: > Hi, > > Why does adding : > > from sage.rings.polynomial.polynomial_ring_constructor import PolynomialRing > > at the beginning of quotient_ring_element.py create the weird error: > > Traceback (most recent call last): > … > AttributeError: 'module' object has no attribute 'quotient_ring' > > Is there a circular dependency problem? If so, how can I possibly create > polynomial rings inside quotient_ring_element ??? > > Cheers, > ---- > Charles Bouillaguet > http://www.lifl.fr/~bouillaguet/ > > -- > You received this message because you are subscribed to the Google Groups > "sage-devel" group. > To post to this group, send email to sage-devel@googlegroups.com. > To unsubscribe from this group, send email to > sage-devel+unsubscr...@googlegroups.com. > Visit this group at http://groups.google.com/group/sage-devel?hl=en. > > --- Charles Bouillaguet http://www.lifl.fr/~bouillaguet/ -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To post to this group, send email to sage-devel@googlegroups.com. To unsubscribe from this group, send email to sage-devel+unsubscr...@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel?hl=en.
