Re: [sage-support] Cannot factor 71281426948143699070565 with ecm.factor()
For me, with SageMath version 9.8.beta7
sage: ecm.factor(71281426948143699070565)
does not return quickly either.
Indeed, running
sage: ecm.interact()
seems to show a strange behaviour for 71281426948143699070565 when
factoring the factors found.
As this is probabilistic and the output changes every time, I do not copy
it here.
Guillermo
On Sun, 29 Jan 2023 at 15:41, Bill Witzke wrote:
> Hi,
>
> I have a hard time factoring the number 71281426948143699070565 using
> ecm.factor(). No result is given after a few minutes runtime. Though,
> plain factor() happily factors the number. Factoring smaller or larger
> numbers work fine with ecm.factor(), too. Just the single given number
> seems to be problematic.
>
> Am I doing something wrong? Can someone confirm?
>
> system:
> Ubuntu 22.04
> sagemath 9.5-4 (via apt)
> Intel Pentium N5000
> (SageMath and Python beginner)
>
> example code factoring numbers in the range [71281426948143699070565 - L,
> 71281426948143699070565 + L]:
>
> # Odd number.
> n = 71281426948143699070565
> # Limit.
> L = 2
> # Iterate over interval [-L, L].
> for i in range(-L, L + 1):
> m = n + i
> print("%d => %s" % (m, ecm.factor(m)))
>
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Re: [sage-support] Cannot factor 71281426948143699070565 with ecm.factor()
Thanks Dima, you taught me something new today.
Guillermo
On Sun, 29 Jan 2023 at 20:50, Dima Pasechnik wrote:
> On Sun, Jan 29, 2023 at 3:04 PM G. M.-S. wrote:
> >
> > For me, with SageMath version 9.8.beta7
> > sage: ecm.factor(71281426948143699070565)
> > does not return quickly either.
> > Indeed, running
> > sage: ecm.interact()
> > seems to show a strange behaviour for 71281426948143699070565 when
> factoring the factors found.
> > As this is probabilistic and the output changes every time, I do not
> copy it here.
>
> Basically, the default B1 value is too large in this case.
>
> sage: ecm.factor(71281426948143699070565,B1=200) # almost instant
> [5, 53, 337, 1873, 2833, 7507, 20037791]
> sage: ecm.factor(71281426948143699070565,B1=2000) # takes looong time
>
> the docs say:
>
>* "B1" -- initial lower bound, defaults to 2000 (15 digit factors).
> Used if "factor_digits" is not specified.
>
> > Guillermo
> >
> > On Sun, 29 Jan 2023 at 15:41, Bill Witzke wrote:
> >>
> >> Hi,
> >>
> >> I have a hard time factoring the number 71281426948143699070565 using
> ecm.factor(). No result is given after a few minutes runtime. Though,
> plain factor() happily factors the number. Factoring smaller or larger
> numbers work fine with ecm.factor(), too. Just the single given number
> seems to be problematic.
> >>
> >> Am I doing something wrong? Can someone confirm?
> >>
> >> system:
> >> Ubuntu 22.04
> >> sagemath 9.5-4 (via apt)
> >> Intel Pentium N5000
> >> (SageMath and Python beginner)
> >>
> >> example code factoring numbers in the range [71281426948143699070565 -
> L, 71281426948143699070565 + L]:
> >>
> >> # Odd number.
> >> n = 71281426948143699070565
> >> # Limit.
> >> L = 2
> >> # Iterate over interval [-L, L].
> >> for i in range(-L, L + 1):
> >> m = n + i
> >> print("%d => %s" % (m, ecm.factor(m)))
>
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[sage-support] Cannot factor 71281426948143699070565 with ecm.factor()
Hi,
I have a hard time factoring the number 71281426948143699070565 using
ecm.factor(). No result is given after a few minutes runtime. Though,
plain factor() happily factors the number. Factoring smaller or larger
numbers work fine with ecm.factor(), too. Just the single given number
seems to be problematic.
Am I doing something wrong? Can someone confirm?
system:
Ubuntu 22.04
sagemath 9.5-4 (via apt)
Intel Pentium N5000
(SageMath and Python beginner)
example code factoring numbers in the range [71281426948143699070565 - L,
71281426948143699070565 + L]:
# Odd number.
n = 71281426948143699070565
# Limit.
L = 2
# Iterate over interval [-L, L].
for i in range(-L, L + 1):
m = n + i
print("%d => %s" % (m, ecm.factor(m)))
--
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Re: [sage-support] Cannot factor 71281426948143699070565 with ecm.factor()
On Sun, Jan 29, 2023 at 3:04 PM G. M.-S. wrote:
>
>
> For me, with SageMath version 9.8.beta7
>
> sage: ecm.factor(71281426948143699070565)
>
> does not return quickly either.
>
> Indeed, running
>
> sage: ecm.interact()
>
> seems to show a strange behaviour for 71281426948143699070565 when factoring
> the factors found.
> As this is probabilistic and the output changes every time, I do not copy it
> here.
Basically, the default B1 value is too large in this case.
sage: ecm.factor(71281426948143699070565,B1=200) # almost instant
[5, 53, 337, 1873, 2833, 7507, 20037791]
sage: ecm.factor(71281426948143699070565,B1=2000) # takes looong time
the docs say:
* "B1" -- initial lower bound, defaults to 2000 (15 digit factors).
Used if "factor_digits" is not specified.
>
> Guillermo
>
> On Sun, 29 Jan 2023 at 15:41, Bill Witzke wrote:
>>
>> Hi,
>>
>> I have a hard time factoring the number 71281426948143699070565 using
>> ecm.factor(). No result is given after a few minutes runtime. Though,
>> plain factor() happily factors the number. Factoring smaller or larger
>> numbers work fine with ecm.factor(), too. Just the single given number
>> seems to be problematic.
>>
>> Am I doing something wrong? Can someone confirm?
>>
>> system:
>> Ubuntu 22.04
>> sagemath 9.5-4 (via apt)
>> Intel Pentium N5000
>> (SageMath and Python beginner)
>>
>> example code factoring numbers in the range [71281426948143699070565 - L,
>> 71281426948143699070565 + L]:
>>
>> # Odd number.
>> n = 71281426948143699070565
>> # Limit.
>> L = 2
>> # Iterate over interval [-L, L].
>> for i in range(-L, L + 1):
>> m = n + i
>> print("%d => %s" % (m, ecm.factor(m)))
>
>
>
> --
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> email to sage-support+unsubscr...@googlegroups.com.
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Re: [sage-support] Cannot factor 71281426948143699070565 with ecm.factor()
dim...@gmail.com schrieb am Sonntag, 29. Januar 2023 um 20:50:29 UTC+1: Basically, the default B1 value is too large in this case. sage: ecm.factor(71281426948143699070565,B1=200) # almost instant [5, 53, 337, 1873, 2833, 7507, 20037791] sage: ecm.factor(71281426948143699070565,B1=2000) # takes looong time the docs say: * "B1" -- initial lower bound, defaults to 2000 (15 digit factors). Used if "factor_digits" is not specified. Thanks, that works! Still, I'm puzzled in what way the default B1 value were too large? I mean, other numbers of the same magnitude are factored fine with B1=2000. -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-support/79866056-a078-41d9-89da-e9029a115ebbn%40googlegroups.com.
[sage-support] Cannot build Sage 9.8 on Ubuntu 22.04.1 LTS
Hello, I've been trying to build Sage 9.8 from source for development; I had previously done so months ago, but I had not been able to do rebuild Sage since pulling from the GitHub repository around late December/early January. I've deleted the previous source/build directory that I had to try building from source all over again to no avail. Attached is a copy of the logs subdirectory. Thank you for your help, Hyun Jong -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-support/a7dd8f03-4ed7-4280-849a-5bc6a26e6aebn%40googlegroups.com. <>
