#11316: Weighted degree term orders added
----------------------------------------------------------------+-----------
Reporter: klee |
Owner: AlexGhitza
Type: enhancement |
Status: needs_work
Priority: major |
Milestone: sage-4.7.1
Component: basic arithmetic |
Keywords:
Work_issues: Singular conversion with negative degree weights |
Upstream: N/A
Reviewer: |
Author: Kwankyu Lee
Merged: |
Dependencies:
----------------------------------------------------------------+-----------
Changes (by SimonKing):
* status: needs_review => needs_work
* work_issues: => Singular conversion with negative degree weights
Comment:
I am checking the documentation, and tried to add some more examples that
expose the use of degree weights, and I found one problem.
In the documentation, there is no statement on what values are allowed as
degree weights. So, I assume that any real number is allowed (but this
should be stated in the docs as well). In particular, negative degree
weights should be allowed (this is something that I use in my current
project).
So, I tested
{{{
sage: N.<a,b,c> = PolynomialRing(QQ, 3,
order=TermOrder('wdeglex',[-1,2,-3]))
sage: c<a^2<1
True
}}}
which is correct.
But the conversion to Singular fails:
{{{
sage: T = N.term_order()
sage: T.singular_str() # this is correct as well
'Wp(-1,2,-3)'
sage: singular(N)
---------------------------------------------------------------------------
RuntimeError Traceback (most recent call
last)
/mnt/local/king/SAGE/sage-4.7.rc2/devel/sage-main/<ipython console> in
<module>()
/mnt/local/king/SAGE/sage-4.7.rc2/local/lib/python2.6/site-
packages/sage/interfaces/singular.pyc in __call__(self, x, type)
653 return self(x.sage())
654 elif not isinstance(x, ExpectElement) and hasattr(x,
'_singular_'):
--> 655 return x._singular_(self)
656
657 # some convenient conversions
/mnt/local/king/SAGE/sage-4.7.rc2/local/lib/python2.6/site-
packages/sage/rings/polynomial/multi_polynomial_libsingular.so in
sage.rings.polynomial.multi_polynomial_libsingular.MPolynomialRing_libsingular._singular_
(sage/rings/polynomial/multi_polynomial_libsingular.cpp:9291)()
/mnt/local/king/SAGE/sage-4.7.rc2/local/lib/python2.6/site-
packages/sage/rings/polynomial/multi_polynomial_libsingular.so in
sage.rings.polynomial.multi_polynomial_libsingular.MPolynomialRing_libsingular._singular_init_
(sage/rings/polynomial/multi_polynomial_libsingular.cpp:9851)()
/mnt/local/king/SAGE/sage-4.7.rc2/local/lib/python2.6/site-
packages/sage/interfaces/singular.pyc in ring(self, char, vars, order,
check)
903 s = '; '.join(['if(defined(%s)>0){kill %s;};'%(x,x)
904 for x in vars[1:-1].split(',')])
--> 905 self.eval(s)
906
907 if check and isinstance(char, (int, long,
sage.rings.integer.Integer)):
/mnt/local/king/SAGE/sage-4.7.rc2/local/lib/python2.6/site-
packages/sage/interfaces/singular.pyc in eval(self, x, allow_semicolon,
strip, **kwds)
548
549 if s.find("error") != -1 or s.find("Segment fault") != -1:
--> 550 raise RuntimeError, 'Singular error:\n%s'%s
551
552 if get_verbose() > 0:
RuntimeError: Singular error:
? `a` is not defined
? error occurred in or before STDIN line 25: `ill 0*a;};; if(defined(
0*b)>0){kill 0*b;};; if(defined( 0*c)>0){kill 0*c;};`
? `b` is not defined
? error occurred in or before STDIN line 25: `ill 0*a;};; if(defined(
0*b)>0){kill 0*b;};; if(defined( 0*c)>0){kill 0*c;};`
? `c` is not defined
? error occurred in or before STDIN line 25: `ill 0*a;};; if(defined(
0*b)>0){kill 0*b;};; if(defined( 0*c)>0){kill 0*c;};`
}}}
I assume that the example ''should'' work. And in Singular, it ''does''
work:
{{{
SINGULAR / Development
A Computer Algebra System for Polynomial Computations / version 3-1-1
0<
by: G.-M. Greuel, G. Pfister, H. Schoenemann \ Feb 2010
FB Mathematik der Universitaet, D-67653 Kaiserslautern \
> ring r = 0,(a,b,c),Wp(-1,2,-3);
> r;
// characteristic : 0
// number of vars : 3
// block 1 : ordering Wp
// : names a b c
// : weights -1 2 -3
// block 2 : ordering C
}}}
So, I'm putting it as "needs work".
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11316#comment:25>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/sage-trac?hl=en.
