#18600: Fix several methods for sparse polynomials
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Reporter: bruno | Owner:
Type: defect | Status: needs_work
Priority: major | Milestone: sage-6.9
Component: commutative | Resolution:
algebra | Merged in:
Keywords: sparse polynomial | Reviewers: Vincent Delecroix
Authors: Bruno Grenet | Work issues:
Report Upstream: N/A | Commit:
Branch: public/18600 | e75ab73b3b2e0bc3a40105640d0572b1b6af9cea
Dependencies: | Stopgaps:
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Comment (by bruno):
Replying to [comment:11 vdelecroix]:
> - inconsistency between dense and sparse
> {{{
> sage: R.<x> = PolynomialRing(Zmod(4), sparse=False)
> sage: p = x**4 + 1
> sage: p.integral()
> x^5 + x
> sage: R.<x> = PolynomialRing(Zmod(4), sparse=True)
> sage: p = x**4 + 1
> sage: p.integral()
> Traceback (most recent call last):
> ...
> TypeError: self must be an integral domain.
> }}}
Right, I should mimick what you did for the dense case. Before I do this,
I actually have a question on what you wrote:
{{{#!python
cm = sage.structure.element.get_coercion_model()
try:
S = cm.bin_op(R.one(), ZZ.one(), operator.div).parent()
Q = S.base_ring()
except TypeError:
Q = (R.base_ring().one()/ZZ.one()).parent()
S = R.change_ring(Q)
}}}
I don't get what you consider `ZZ.one()` instead of `R.one()` or even
better `R.base_ring.one()`. I have the following behavior:
{{{#!python
sage: R.<x> = Zmod(4)[]
sage: cm.bin_op(R.one(),ZZ.one(),operator.div).parent()
Traceback (most recent call last):
...
TypeError: self must be an integral domain.
sage: cm.bin_op(R.one(),R.one(),operator.div).parent()
Traceback (most recent call last):
...
TypeError: self must be an integral domain.
sage: cm.bin_op(R.one(),R.base_ring().one(),operator.div).parent()
Univariate Polynomial Ring in x over Ring of integers modulo 4
}}}
and
{{{#!python
sage: R.<x> = ZZ[]
sage: cm.bin_op(R.one(),R.base_ring().one(),operator.div).parent()
Univariate Polynomial Ring in x over Rational Field
sage: R.<x> = ZZ['y'][]
sage: cm.bin_op(R.one(),R.base_ring().one(),operator.div).parent()
Univariate Polynomial Ring in x over Fraction Field of Univariate
Polynomial Ring in y over Integer Ring
}}}
If I understand correctly, using `R.base_ring.one()` may fix the issue of
your `TODO`. What do you think of this?
--
Ticket URL: <http://trac.sagemath.org/ticket/18600#comment:12>
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