On 2016-10-22 10:37, Ralf Stephan wrote:
|
sage:2*(QQbar(1))
2
sage:2^(QQbar(1))
...
TypeError:nocanonical coercion fromAlgebraicFieldto RationalField
|
Why does the one work, the other not?
Multiplication uses coercion.
Exponentiation does not use coercion, since that's usually not what you
On Saturday, October 22, 2016 at 6:28:58 PM UTC+2, vdelecroix wrote:
>
> ... The behavior of any operation in Sage is that
> the parent of op(a, b) should only depend on the operator op,
> parent(a) and parent(b). Powers are a bit special but not enough to
> use conversion instead of coercion.
On Sat, 22 Oct 2016 13:18:12 -0700 (PDT)
Volker Braun wrote:
> Thats definitely a SageNB bug, though afaik nobody is maintaining
> that. My recommendation would be to use "sage --notebook=jupyter"
> instead.
>
Perhaps I could try to do that. Is there some guide on replacing the
Sage Notebook ser
Thats definitely a SageNB bug, though afaik nobody is maintaining that. My
recommendation would be to use "sage --notebook=jupyter" instead.
On Saturday, October 22, 2016 at 6:12:03 PM UTC+2, v_...@ukr.net wrote:
>
> Hello!
> I use the Sage Notebook on my server with Sage v.7.4. And each ti
On 22 October 2016 at 19:08, John Cremona wrote:
> On 22 October 2016 at 17:28, Vincent Delecroix
> <20100.delecr...@gmail.com> wrote:
>> On 22 October 2016 at 16:10, Ralf Stephan wrote:
>>> On Saturday, October 22, 2016 at 4:04:55 PM UTC+2, John Cremona wrote:
So Ralf, do you want to
On 22 October 2016 at 17:28, Vincent Delecroix
<20100.delecr...@gmail.com> wrote:
> On 22 October 2016 at 16:10, Ralf Stephan wrote:
>> On Saturday, October 22, 2016 at 4:04:55 PM UTC+2, John Cremona wrote:
>>>
>>> So Ralf, do you want to catch the case where the exponent in QQbar is
>>> actually
On 22 October 2016 at 16:10, Ralf Stephan wrote:
> On Saturday, October 22, 2016 at 4:04:55 PM UTC+2, John Cremona wrote:
>>
>> So Ralf, do you want to catch the case where the exponent in QQbar is
>> actually rational and then do what QQbar already knows how to do
>> (raise to a rational power),
Hello!
I use the Sage Notebook on my server with Sage v.7.4. And each time I try to
open some TXT file in the DATA folder I get the error message in the web
interface
500: Internal server error.
And in the terminal where I started the Sage server, I see this error message:
===
On Saturday, October 22, 2016 at 4:04:55 PM UTC+2, John Cremona wrote:
>
> So Ralf, do you want to catch the case where the exponent in QQbar is
> actually rational and then do what QQbar already knows how to do
> (raise to a rational power), returning an element of QQbar; and raise
> an Error
On 22 October 2016 at 14:44, William Stein wrote:
> On Sat, Oct 22, 2016 at 6:11 AM, John Cremona wrote:
>> On 22 October 2016 at 09:37, Ralf Stephan wrote:
>>> sage: 2*(QQbar(1))
>>> 2
>>> sage: 2^(QQbar(1))
>>> ...
>>> TypeError: no canonical coercion from Algebraic Field to Rational Field
>>>
On Sat, Oct 22, 2016 at 6:11 AM, John Cremona wrote:
> On 22 October 2016 at 09:37, Ralf Stephan wrote:
>> sage: 2*(QQbar(1))
>> 2
>> sage: 2^(QQbar(1))
>> ...
>> TypeError: no canonical coercion from Algebraic Field to Rational Field
>>
>> Why does the one work, the other not? Is it a bug?
>
> I
I see, you're thinking algebraically not computationally. The latter view
would try to convert to QQ, and only then try to coerce, in order to catch
the rational case first and not give an error where none is expected.
On Saturday, October 22, 2016 at 3:11:50 PM UTC+2, John Cremona wrote:
>
> On 2
On 22 October 2016 at 09:37, Ralf Stephan wrote:
> sage: 2*(QQbar(1))
> 2
> sage: 2^(QQbar(1))
> ...
> TypeError: no canonical coercion from Algebraic Field to Rational Field
>
> Why does the one work, the other not? Is it a bug?
I don't see that as a bug. Any product of an integer and an elemen
sage: 2*(QQbar(1))
2
sage: 2^(QQbar(1))
...
TypeError: no canonical coercion from Algebraic Field to Rational Field
Why does the one work, the other not? Is it a bug?
Regards,
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