[GAP Forum] Forum Digest, Vol 151, Issue 3
Fawad Hayat
fawadhayat05 at gmail.com
Fri Jun 24 22:04:31 BST 2016
Dear Forum please I need your response..
thanks
FAWAD ALI
On Fri, Jun 24, 2016 at 2:05 PM, <forum-request at gap-system.org> wrote:
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> Today's Topics:
>
> 1. PartitionsSet (fatemeh moftakhar)
> 2. Re: PartitionsSet (Thomas Breuer)
> 3. ReadLine (fatemeh moftakhar)
> 4. Re: saving variables to a file (Stefan Kohl)
> 5. Announcing the SLA package (Leonard Soicher)
> 6. Announcing the AutomGrp package (Leonard Soicher)
> 7. FAWAD ALI M.Phil (Pure Mathematics) 3rd semester scholar From
> Pakistan, (Fawad Hayat)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 15 Jun 2016 22:21:52 -0700
> From: fatemeh moftakhar <f.k.moftakhar at gmail.com>
> To: forum at gap-system.org
> Subject: [GAP Forum] PartitionsSet
> Message-ID:
> <
> CAOEkHNL7a2wFTZVgiFvu+4fcGPm-bGBeuy1uRbtP_auaQEe3qw at mail.gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> Dear GAP forum
>
> I need all partitions of {2,..,21}. I mean, I want to run
> PartitionsSet([2..21]). I have servers with 512 gigabyte ram and my
> computer stopped after two days, because it needs more ram. I don't have
> better computer. Is there a faster algorithm? I need these partitions for
> computing supercharacter theories of Janko group J2.
>
>
>
> Best regards
> Fatemeh Moftakhar
>
>
>
> --
> Regards;
> Miss Fatemeh Moftakhar
> PhD Candidate,
> Department of Pure Mathematics,
> Faculty of Mathematical Sciences,
> University of Kashan, Kashan, Iran
>
>
> ------------------------------
>
> Message: 2
> Date: Thu, 16 Jun 2016 09:19:01 +0200
> From: Thomas Breuer <sam at Math.RWTH-Aachen.De>
> To: fatemeh moftakhar <f.k.moftakhar at gmail.com>, forum at gap-system.org
> Subject: Re: [GAP Forum] PartitionsSet
> Message-ID: <20160616071900.GA15203 at gemma.math.rwth-aachen.de>
> Content-Type: text/plain; charset=us-ascii
>
> Dear GAP Forum,
>
> Fatemeh Moftakhar wrote
>
> > I need all partitions of {2,..,21}. I mean, I want to run
> > PartitionsSet([2..21]). I have servers with 512 gigabyte ram and my
> > computer stopped after two days, because it needs more ram. I don't have
> > better computer. Is there a faster algorithm? I need these partitions for
> > computing supercharacter theories of Janko group J2.
>
> If you really have to run over all these partitions then
> this will take a lot of time.
> Let us assume that you can process a million of them in a second,
> which would be quite fast.
> In one year (356 days with 24 hours) you can then process
> the following number of partitions.
>
> gap> 10^6 * 3600 * 24 * 356;
> 30758400000000
> gap> NrPartitionsSet( [ 2 .. 21 ] );
> 51724158235372
>
> I would suggest to find criteria that allow you to exclude most of the
> candidates without looking at them.
>
> All the best,
> Thomas
>
> P.S.:
> Even if you really have to look at each element from a large set
> then keeping all of them in memory at the same time is probably
> not necessary.
> For such purposes, one can think about developing a so-called iterator
> for the set.
> This is essentially a function that knows which was the last element
> you have looked at, and can can be called in order to give you the
> next element.
> Such functionality exists already in GAP for several kinds of sets,
> for example for the set of partitions of a given number.
> I am not aware of iterator functionality for the set of partitions
> of a set,
> but the above numbers show that this approach would not be suitable
> in your situation.
>
>
>
>
> ------------------------------
>
> Message: 3
> Date: Thu, 16 Jun 2016 00:33:21 -0700
> From: fatemeh moftakhar <f.k.moftakhar at gmail.com>
> To: forum at gap-system.org
> Subject: [GAP Forum] ReadLine
> Message-ID:
> <CAOEkHN+9kuySFYmOBPDp5GHR+GhGNJ=
> QW2paWJDhS9NUD47D6w at mail.gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> Dear GAP forum
>
> Is there any way to read just a special line of a large file (that has too
> much data). Would you please explain with a sample code?
>
> Best regards
> Fatemeh Moftakhar
>
> --
> Regards;
> Miss Fatemeh Moftakhar
> PhD Candidate,
> Department of Pure Mathematics,
> Faculty of Mathematical Sciences,
> University of Kashan, Kashan, Iran
>
>
> ------------------------------
>
> Message: 4
> Date: Fri, 17 Jun 2016 00:14:07 +0100 (BST)
> From: "Stefan Kohl" <stefan at mcs.st-and.ac.uk>
> To: "R.N. Tsai" <r_n_tsai at yahoo.com>
> Cc: GAP Forum <forum at gap-system.org>
> Subject: Re: [GAP Forum] saving variables to a file
> Message-ID: <submission.1bDgUC-0005L1-0i at mail-gap.mcs.st-and.ac.uk>
> Content-Type: text/plain;charset=iso-8859-1
>
> On Thu, June 16, 2016 12:35 am, R.N. Tsai wrote:
> > This is actually perfect for GF(2) matrices (which is all I need for
> now).Interestingly
> > enough if I convert the GF(2) matrix to 1 and 0's (using "Int") the
> bitmapfile is 24x
> > larger...
>
> Yes -- if you take an integer matrix, you get a 24-bit color picture,
> where the
> entries of the matrix are read as 256^2 * red value + 256 * green value +
> blue value.
>
> Stefan
>
> > From: Stefan Kohl <stefan at mcs.st-and.ac.uk>
> > To: R.N. Tsai <r_n_tsai at yahoo.com>
> > Cc: Max Horn <max at quendi.de>; GAP Forum <forum at gap-system.org>
> > Sent: Wednesday, June 15, 2016 1:51 PM
> > Subject: Re: [GAP Forum] saving variables to a file
> >
> > On Tue, June 14, 2016 5:20 pm, R.N. Tsai wrote:
> >> Thanks for the response Max,The matrices are over GF(2), so hopefully
> they can be
> >> managed more efficiently than generic matrices.R.N
> >
> > One thing you could do specifically for matrices over GF(2) is to save
> them
> > as monochrome bitmap pictures -- this uses just one bit per entry (plus
> a tiny
> > overhead for the description block for the picture):
> >
> > gap> M := NullMat(10000,10000,GF(2));; # just some GF(2) matrix, could
> be any
> > gap> file := Filename(DirectoryTemporary(),"matrix.bmp"); # pick a file
> name
> > "/tmp/tmIthaXA/matrix.bmp"
> > gap> SaveAsBitmapPicture(M,file); # save the matrix to the file, 12.5 MB
> in this case
> > gap> time;
> > 18392
> > gap> N := LoadBitmapPicture(file);; # read it in again
> > gap> time;
> > 8320
> > gap> N = M;
> > true
> >
> > Hope this helps,
> >
> > ?? ?? Stefan
> >
> >
> >
> >
> >
>
>
>
>
> ------------------------------
>
> Message: 5
> Date: Tue, 21 Jun 2016 08:38:55 +0000
> From: Leonard Soicher <l.h.soicher at qmul.ac.uk>
> To: "forum at gap-system.org" <forum at gap-system.org>
> Subject: [GAP Forum] Announcing the SLA package
> Message-ID:
> <
> VI1PR07MB084605159C07DB25A4FAAD388E2B0 at VI1PR07MB0846.eurprd07.prod.outlook.com
> >
>
> Content-Type: text/plain; charset="iso-8859-1"
>
>
> Dear Forum Members,
>
> It is my pleasure to announce formally the official acceptance
> of the SLA package. The officially accepted version 1.1 of SLA has
> been publicly available in GAP starting with GAP version 4.8.2,
> and I apologise for the lateness of this announcement.
>
> SLA provides functions for computing with various aspects of
> the theory of simple Lie algebras in characteristic zero.
>
> The SLA package is authored by Willem de Graaf (University of Trento),
> and on behalf of the GAP Council, I thank him for this contribution to GAP.
>
> Leonard Soicher
> (Chair of the GAP Council)
>
>
>
> ------------------------------
>
> Message: 6
> Date: Tue, 21 Jun 2016 09:25:56 +0000
> From: Leonard Soicher <l.h.soicher at qmul.ac.uk>
> To: "forum at gap-system.org" <forum at gap-system.org>
> Subject: [GAP Forum] Announcing the AutomGrp package
> Message-ID:
> <
> VI1PR07MB0846F9DF39864EBF0031D7498E2B0 at VI1PR07MB0846.eurprd07.prod.outlook.com
> >
>
> Content-Type: text/plain; charset="iso-8859-1"
>
>
> Dear Forum Members,
>
> It is my pleasure to announce formally the official acceptance
> of the AutomGrp package. The officially accepted version 1.3 of AutomGrp
> is now available in the newly released GAP version 4.8.4.
>
> AutomGrp provides methods for computations with groups and semigroups
> generated by finite automata or given by wreath recursion, as well as with
> their
> finitely generated subgroups and elements.
>
> The AutomGroup package is authored by Yevgen Muntyan (Tableau Software)
> and Dmytro Savchuk (University of South Florida), and on behalf of the GAP
> Council,
> I thank them for this contribution to GAP.
>
> Leonard Soicher
> (Chair of the GAP Council)
>
>
>
>
> ------------------------------
>
> Message: 7
> Date: Fri, 24 Jun 2016 05:05:38 -0400
> From: Fawad Hayat <fawadhayat05 at gmail.com>
> To: forum at gap-system.org
> Subject: [GAP Forum] FAWAD ALI M.Phil (Pure Mathematics) 3rd semester
> scholar From Pakistan,
> Message-ID:
> <CAPf56+XPam8ZVUyXwNdsvDbLQgqWhYuL=
> 2LyD21qwKmVSYWWzg at mail.gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> Hello sir,
> sir I have a problem that how to write a command in GAP the automorphism
> group of finite abelian group and their fixed points.
> Let Z_pXZ_q be cyclic group where p & q are distinct primes,
> Let suppose p=2 & q=3
> => G:=Z_2XZ_3= {(0,0),(0,1),(0,2),(1,0),(1,1),(1,2)}
> be a cyclic group, and 'd' is the divisor of the order of a group G i.e (
> d/IGI =>d=1,2,3,6)
> how to list all the automorphisms of a group Aut(G), and how to find
> explicitly all those automorphisms fixing 'd' elements, where fix means
> f(x)=x ; for some x belongs to G & for f belongs to Aut(G).
> f(e)=e : by homomorphism property,
>
> i.e For d=1,
> A={set of all those automorphisms of Aut(G) fixing d=1 element only (
> Identity element)}
> For d=2,
> B={set of all those automorphisms of Aut(G) fixing d=2 element}
> For d=3
> C={set of all those automorphisms of Aut(G) fixing d=3 element}
> For d=6
> D={ I : because identity is the only auto fixing all the elements of a
> group G }
>
> Sir, I need The command which gives me the complete calculation from GAP
> Thanks Sir,
> Regards FAWAD ALI From pakistan
>
>
> ------------------------------
>
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> End of Forum Digest, Vol 151, Issue 3
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