2009/9/2 Martin Albrecht <[email protected]>:
>
>> > doc/en/constructions/rings.rst +58
>> >    sage: R = singular.ring(97, '(a,b,c,d)', 'lp')
>> >    sage: I = singular.ideal(['a+b+c+d', 'ab+ad+bc+cd',
>> > 'abc+abd+acd+bcd', 'abcd-1'])
>> >    sage: R
>> > Expected:
>> >    //   characteristic : 97
>> >    //   number of vars : 4
>> >    //        block   1 : ordering lp
>> >    //                  : names    a b c d
>> >    //        block   2 : ordering C
>> > Got:
>> >    //   characteristic : 97
>> >    //   number of vars : 4
>> >    //        block   1 : ordering lp
>> >    //                  : names    abcd
>> >    //        block   2 : ordering C
>> > * The sage spkg don't have a patch to separate the names, so I am
>> > assuming it is a minor change in singular
>>
>> looks safe
>
> Yes, this was fixed in Singular recently, I assume Mandriva only needs to
> update to the newest upstream release.

  I tried again a newer singular, but singular-3-1-0-4, which is the latest one
api/abi compatible with sage. I am preferring to package upstream, and
then apply sage patches as appropriate. I will check if I can make a simple
patch make singular provide the result expected by sage.

>> > rings/polynomial/toy_d_basis.py +171
>> >        sage: from sage.rings.polynomial.toy_d_basis import gpol
>> >        sage: P.<x, y, z> = PolynomialRing(IntegerRing(), 3, order='lex')
>> >        sage: f = x^2 - 1
>> >        sage: g = 2*x*y - z
>> >        sage: gpol(f,g)
>> > Expected:
>> >    x^2*y - y
>> > Got:
>> >    x^2*y - x*z + y
>> > * Not sure what is the cause, neither if this is an alternate correct
>> > result...]
>>
>> Martin -- any thoughts?
>
> Here is what gpol does
>
>  a1,a2 = g1.lc(),g2.lc()# a1 = 1, a2 = 2
>  a, c1, c2 = xgcd(a1,a2) # (1,0,1) -> this is not unique
>  t1,t2 = g1.lm(), g2.lm() # x^2, x*y
>  t = t1.parent().monomial_lcm(t1,t2) # x^2*y
>  s1,s2 = t//t1, t//t2 # y, x
>  return c1*s1*g1 + c2*s2*g2 # 0*y*g1 + 1*x*g2
>
> I guess xgcd changed (e.g. (1,-1,1)) and thus the result is different. So it
> seems also correct.

  Many thanks for the review. About quaddouble, since only sagemath requires
it, I packaged the sage spkg in Mandriva. But the package is kind problematic,
as it has only a static library, and the sage spkg fails to build the fortran
bindings in x86_64. Anyway, if sage stops using it, then it can be dropped
from Mandriva later.

  Since there is still some time before Mandriva 2010.0, I am also updating the
package to ship sage 4.1.1.

> Cheers,
> Martin

Paulo

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