I opened issue #35696 <https://github.com/sagemath/sage/issues/35696> for
this, and put a diagnosis there.
On Monday, May 29, 2023 at 10:00:05 PM UTC-6 dmo...@deductivepress.ca wrote:
> I'm surprised that this hasn't been reported previously, because we can
> get a crash even without atan or any division:
>
> sin( x*(x+1) - x^2 - x ) # this crashes sage
>
> This also crashes with sinh or cos or tan in the place of sin, but not
> with exp or log.
>
> PS I verified on CoCalc that this is not a new bug: this crashes version
> 9.1.
>
> On Monday, May 29, 2023 at 5:51:28 PM UTC-6 Nils Bruin wrote:
>
>> Localized a bit further:
>>
>> var("q A")
>> p = A*(1+1/A)-A-1
>> V=(q^p)._maxima_().rectform()
>>
>> after this, V._sage_() crashes, and I think it's the same crash as above.
>>
>> Transcribing what V is in maxima, we get:
>>
>>
>> I*sin(atan2(0,q)*((1/A+1)*A-A-1))*abs(q)^((1/A+1)*A-A-1)+cos(atan2(0,q)*((1/A+1)*A-A-1))*abs(q)^((1/A+1)*A-A-1)
>>
>> which indeed causes a crash when input directly into sage. More simply:
>>
>> var("q A")
>> U=atan2(0,q)*((1/A+1)*A-A-1)
>> sin(U) #this crashes
>>
>> It looks like an infinite recursion, so probably the constructor (of
>> sin?) tries to do some simplification, which ends up trying to construct
>> the same expression again. The traceback implicates Pynac.
>>
>>
>> On Monday, 29 May 2023 at 13:07:50 UTC-7 dwb...@gmail.com wrote:
>>
>>> I was shown the following way of getting a segmentation fault in Sage.
>>>
>>> sage: var("q A")
>>> sage: p = A*(1+1/A)-A-1
>>> sage: (q^p).full_simplify()
>>>
>>> This consistently causes a crash. The person who found it was doing some
>>> actual work, got a crash, and boiled it down to a minimal example.
>>>
>>> Daniel Bump
>>>
>>
--
You received this message because you are subscribed to the Google Groups
"sage-devel" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sage-devel+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/sage-devel/018e0d18-5810-4a37-9ddf-ef583ce6649bn%40googlegroups.com.
