#11847: unexpexted behavior of degree() with matrix ordering
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Reporter: john_perry | Owner: malb
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-4.7.2
Component: commutative algebra | Keywords: degree, polynomial,
singular
Work_issues: | Upstream: Not yet reported
upstream; Will do shortly.
Reviewer: | Author: john_perry
Merged: | Dependencies: sage 4.7.2
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Comment(by john_perry):
Replying to [comment:7 klee]:
> Replying to [comment:6 mderickx]:
> > We could also add a keyword "use_grading" to the degree methods.
> Simon would think the "use_grading" keyword redundant because degree
methods must always use grading. Perhaps keyword "use_default_grading" is
more sensible. Anyway, using a long keyword is an overkill.
Using a keyword is a great idea. What about calling it `standard_grading`
or (if that's too long) `std_grading`? For reasons of compatibility, the
default would be `False`; when `True`, it uses the standard grading to
compute `degree()` and `total_degree()`.
OTOH I could see setting the default to `True` and raising a deprecation
warning, since matrix orderings haven't been in Sage for very long. (Have
they?) But that seems dicier.
> I think degee methods are for polynomials while exponent methods are for
monomials.
There's a strong case to be made for using monomials (efficiency, for
example) but I also think that's a separate discussion, for a separate
ticket. AFAIK Singular doesn't distinguish the two.
> So it should be more convenient to use exponent methods with monomials.
It would even be reasonable to raise an error if f is not a monomial in
f.exponents()...
I would prefer not to deprecate old ways of doing things unless they were
actually wrong or demonstrably dangerous. I don't think that's the case
here, but maybe I'm wrong.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11847#comment:8>
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