Re: [sage-devel] Error concerning the function "is_prime"
The package in question is downgraded to an experimental one.
A robust and efficient replacement, implementing modular decomposition
of graphs (and digraphs), for the corresponding functionality would be
great.
Perhaps this should be made a GSoC project?
On Tuesday, January 31, 2017 at 3:54:12 PM UTC, kcrisman wrote:
>
>
>
> On Monday, January 30, 2017 at 9:48:22 AM UTC-5, Thierry
> (sage-googlesucks@xxx) wrote:
>>
>> Hi,
>>
>> On Mon, Jan 30, 2017 at 03:44:06AM -0800, jamel Dammak wrote:
>> > Dear sir,
>> >
>> > there is an error concerning the function "is_prime" for graphs in
>> > Sagemath, section Graph Theory.
>> >
>> > Here is a conter-example.
>> >
>> > g1=Graph({0:[1,4],1:[0,2,4],2: [1,3,4],3:[2],4:[0,1,2]});g2=G
>> > raph({0:[1],1:[0,2,4],2:[1,3,4 ],3:[2,4],4:[1,2,3]})
>> > #g1.show();g2.show();
>> > #[1,4] is a module of g1 so g1 is not prime
>> > #[2,4] is a module of g2 so g2 is not prime
>> > g2.is_isomorphic(g1), g1.is_prime(),g2.is_prime()
>> >
>> > This is a conter-example with two isomorphic graphs g1 and g2 on 5
>> > vertices giving two different results
>> > with the function "is prime".
>> >
>> > I have an algorithm giving the list of all prime graphs on at most 8
>> > vertices.
>>
>>
>> Great, go ahead, ask for a trac account, and propose your changes.
>>
>
> I've reported this at https://trac.sagemath.org/ticket/22281
> Note it depends on an optional package, so this may be part of the issue.
>
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Re: [sage-devel] Error concerning the function "is_prime"
> > >> > I have an algorithm giving the list of all prime graphs on at most 8 >> > vertices. >> >> >> Great, go ahead, ask for a trac account, and propose your changes. >> > > I've reported this at https://trac.sagemath.org/ticket/22281 > Note it depends on an optional package, so this may be part of the issue. > For reference, this turned out to be https://trac.sagemath.org/ticket/13744 Separately, you are still welcome to submit any "Sage-native" code for review, but you would want to open a separate ticket for that as an enhancement (as opposed to fixing the bug). -- 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 post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
Re: [sage-devel] Error concerning the function "is_prime"
On Monday, January 30, 2017 at 9:48:22 AM UTC-5, Thierry
(sage-googlesucks@xxx) wrote:
>
> Hi,
>
> On Mon, Jan 30, 2017 at 03:44:06AM -0800, jamel Dammak wrote:
> > Dear sir,
> >
> > there is an error concerning the function "is_prime" for graphs in
> > Sagemath, section Graph Theory.
> >
> > Here is a conter-example.
> >
> > g1=Graph({0:[1,4],1:[0,2,4],2: [1,3,4],3:[2],4:[0,1,2]});g2=G
> > raph({0:[1],1:[0,2,4],2:[1,3,4 ],3:[2,4],4:[1,2,3]})
> > #g1.show();g2.show();
> > #[1,4] is a module of g1 so g1 is not prime
> > #[2,4] is a module of g2 so g2 is not prime
> > g2.is_isomorphic(g1), g1.is_prime(),g2.is_prime()
> >
> > This is a conter-example with two isomorphic graphs g1 and g2 on 5
> > vertices giving two different results
> > with the function "is prime".
> >
> > I have an algorithm giving the list of all prime graphs on at most 8
> > vertices.
>
>
> Great, go ahead, ask for a trac account, and propose your changes.
>
I've reported this at https://trac.sagemath.org/ticket/22281
Note it depends on an optional package, so this may be part of the issue.
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Re: [sage-devel] Error concerning the function "is_prime"
Hi,
On Mon, Jan 30, 2017 at 03:44:06AM -0800, jamel Dammak wrote:
> Dear sir,
>
> there is an error concerning the function "is_prime" for graphs in
> Sagemath, section Graph Theory.
>
> Here is a conter-example.
>
> g1=Graph({0:[1,4],1:[0,2,4],2: [1,3,4],3:[2],4:[0,1,2]});g2=G
> raph({0:[1],1:[0,2,4],2:[1,3,4 ],3:[2,4],4:[1,2,3]})
> #g1.show();g2.show();
> #[1,4] is a module of g1 so g1 is not prime
> #[2,4] is a module of g2 so g2 is not prime
> g2.is_isomorphic(g1), g1.is_prime(),g2.is_prime()
>
> This is a conter-example with two isomorphic graphs g1 and g2 on 5
> vertices giving two different results
> with the function "is prime".
>
> I have an algorithm giving the list of all prime graphs on at most 8
> vertices.
Great, go ahead, ask for a trac account, and propose your changes.
http://doc.sagemath.org/html/en/faq/faq-contribute.html
Ciao,
Thierry
>
> Best regards.
>
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[sage-devel] Error concerning the function "is_prime"
Dear sir,
there is an error concerning the function "is_prime" for graphs in
Sagemath, section Graph Theory.
Here is a conter-example.
g1=Graph({0:[1,4],1:[0,2,4],2: [1,3,4],3:[2],4:[0,1,2]});g2=G
raph({0:[1],1:[0,2,4],2:[1,3,4 ],3:[2,4],4:[1,2,3]})
#g1.show();g2.show();
#[1,4] is a module of g1 so g1 is not prime
#[2,4] is a module of g2 so g2 is not prime
g2.is_isomorphic(g1), g1.is_prime(),g2.is_prime()
This is a conter-example with two isomorphic graphs g1 and g2 on 5
vertices giving two different results
with the function "is prime".
I have an algorithm giving the list of all prime graphs on at most 8
vertices.
Best regards.
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