Burcin Erocal wrote:
> On Sun, 19 Apr 2009 10:34:21 -0700
> Carl Witty <carl.wi...@gmail.com> wrote:
>
>> On Sun, Apr 19, 2009 at 7:44 AM, Maurizio
>> <maurizio.gran...@gmail.com> wrote:
>>> Carl, I took advantage of your suggestion, even though I assume I
>>> can't still go through the whole process with the current gcd
>>> capabilities in Pynac. But before than that, I'd like to point out
>>> something strange I did notice, and maybe also Burcin can help with
>>> that:
>>>
>>> reset()
>>> P.<x,z> = QQ[]
>>>
>>> B = x^3 + x
>>>
>>> var('x, zs', ns = 1)
>>> from sage.symbolic.ring import NSR
>>> Bs = NSR(B)
>>> Bs
>>> x^3 + x
>>> Bs.diff(x)
>>> 0
>>>
>>> So, the derivative is not working. Which is the cause? It seems that
>>> the "x" in Bs is not the "x" I declared, so the derivative gets 0
>>> as a result. Which is the reason?
>> Looks like a bug to me.
>>
>> Burcin, any comments?
>
> I agree that it's confusing, but it's not a bug.
>
> The command
>
> sage: Bs = NSR(B)
>
> converts the polynomial B = x^3 + x in QQ[x] to a symbolic expression,
> with one numeric coefficient, namely B.
So is this what happens anytime you do NSR(sage_object)? It converts it
to a constant (as far as symbolics is concerned) with a coefficient of
sage_object? Or are there any exceptions?
Jason
--
Jason Grout
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