Janko Groups and Livingstone graph #18774

nathanncohen · 2015-06-23T12:45:36Z

This branch exposes the Janko groups from gap, and builds the Livingstone Graph from J1

https://en.wikipedia.org/wiki/Janko_group
https://en.wikipedia.org/wiki/Livingstone_graph

Nathann

CC: @dimpase @videlec

Component: group theory

Author: Nathann Cohen

Branch/Commit: d07e879

Reviewer: Dima Pasechnik

Issue created by migration from https://trac.sagemath.org/ticket/18774

The text was updated successfully, but these errors were encountered:

nathanncohen · 2015-06-23T12:46:12Z

Commit: 42e61b8

nathanncohen · 2015-06-23T12:46:12Z

Branch: public/18774

nathanncohen · 2015-06-23T12:46:12Z

New commits:

`42e61b8`	`trac #18774: Livingstone Graph and Janko Groups`

sagetrac-git · 2015-06-23T12:58:00Z

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

`8b7160a`	`trac #18774: Livingstone Graph and Janko Groups`

sagetrac-git · 2015-06-23T12:58:00Z

Changed commit from 42e61b8 to 8b7160a

dimpase · 2015-06-23T19:39:11Z

comment:3

JankoGroup(4) should throw NotImplementedError; I don't think anyone wants a permutation
group of degree 173067389, and they aren't known by AtlasRep, as far as I know (IMHO
they have the same data as in http://brauer.maths.qmul.ac.uk/Atlas/v3/spor/J4/).

gap> i:=AtlasGroup("J4");
<matrix group of size 86775571046077562880 with 2 generators>

while for the remaining values of k<4 you get

gap> i:=AtlasGroup("Jk");
<permutation group of size ....... with 2 generators>

sagetrac-git · 2015-06-23T21:38:17Z

Changed commit from 8b7160a to 7efe54b

sagetrac-git · 2015-06-23T21:38:17Z

Branch pushed to git repo; I updated commit sha1. New commits:

`7efe54b`	`trac #18774: no J4`

nathanncohen · 2015-06-23T21:39:06Z

comment:5

Hello,

JankoGroup(4) should throw NotImplementedError;

Right, right. I simplified it and requested an integer from 1 to 3 instead.

Nathann

fchapoton · 2015-06-25T07:47:38Z

comment:6

tests do not pass

shouldn't this be tagged optional - gap_something ?

nathanncohen · 2015-06-25T07:49:51Z

comment:7

shouldn't this be tagged optional - gap_something ?

HMmm... Gap isn't optional. And with gap installed on my computer, I did not notice that an optional package was needed ^^;

I don't even know which package is needed O_o

Nathann

dimpase · 2015-06-25T07:51:32Z

comment:8

you need internet access to use AtlasRep in GAP.
I also think that AtlasRep comes in gap_packages, i.e. is optional.

(I'm currently travelling, so please excuse my non-constant attention)

nathanncohen · 2015-06-25T07:53:01Z

comment:9

Hellooooo !

you need internet access to use AtlasRep in GAP.

Whaaaaaaaaat ? I'll check this immediately.

I also think that AtlasRep comes in gap_packages, i.e. is optional.

Yep. It is inside.

Nathann

sagetrac-git · 2015-06-25T07:58:03Z

Branch pushed to git repo; I updated commit sha1. New commits:

`93801c8`	`trac #18774: optional gap packages`

sagetrac-git · 2015-06-25T07:58:03Z

Changed commit from 7efe54b to 93801c8

nathanncohen · 2015-06-25T07:58:27Z

comment:11

It works offline, but gap_packages must be installed.

dimpase · 2015-06-25T08:17:57Z

comment:12

Replying to @nathanncohen:

It works offline,

Really? http://www.math.rwth-aachen.de/~Thomas.Breuer/atlasrep/ (the official www-pages of the package) says

 Note that the package archives do NOT contain the database part of the package; the GAP interface accesses the data on demand via the internet.

nathanncohen · 2015-06-25T08:20:19Z

comment:13

Really?

I built if offline. You think that they have a caching mechanism for that, between sessions?...

Nathann

dimpase · 2015-06-25T08:25:48Z

comment:14

Replying to @nathanncohen:

Really?

I built if offline. You think that they have a caching mechanism for that, between sessions?...

of course you can build it offline, but not use offline
(although perhaps some of its data is in other GAP databases).

perhaps one has to read its code...

Nathann

dimpase · 2015-06-25T08:30:07Z

comment:15

TFM says:

4.3 User Parameters for the AtlasRep Package

This section lists global parameters for which it might make sense to change their defaults by assignments to global variables, either just for the current GAP session or as user preferences in the user's gaprc file (see Reference: The gap.ini and gaprc files). For an overview of these parameters, see AtlasOfGroupRepresentationsUserParameters (4.3-8).

4.3-1 Local or Remote Access

There are two possibilities to use the AtlasRep package.

Local access only (offline)

    You can restrict the access to the data that are actually stored in the local installation of GAP.
Remote access (online)

    If your computer is connected to a network that provides access to the ATLAS data (for example the internet) then the functions of the package may fetch the requested data automatically from remote servers when they are required for the first time; these data are then by default stored in the local copy, so later access to them needs no network transfer.

The latter possibility is presently not used by other GAP packages, so it may be regarded as an important feature of the AtlasRep package. Anyhow it requires a few words of explanation.
...

nathanncohen · 2015-06-25T08:30:43Z

comment:16

I just did the following:

Went offline
'sage -f gap_packages'
'rm -rf ~/.sage/gap/'
'make'
'sage -br'

sage: graphs.LivingstoneGraph()
Livingstone Graph: Graph on 266 vertices

So for the moment, I will keep on believing that this works offline. Unless you know where it could be cached?

Nathann

dimpase · 2015-06-25T08:37:44Z

comment:17

Replying to @nathanncohen:

So for the moment, I will keep on believing that this works offline. Unless you know where it could be cached?

RTFM?

Then, there is stuff in $SAGE_LOCAL/gap

nathanncohen · 2015-06-25T08:43:02Z

comment:18

RTFM?

Always a pleasure to work with you dima.

Then, there is stuff in $SAGE_LOCAL/gap

Yeah, I just figured this out offline. The thing is that you are not supposed to have writing access to SAGE_LOCAL/gap, so no information should be cached there. It should be done in ~/.sage/gap

Anyway, this requires internet indeed.

Nathann

sagetrac-git · 2015-06-25T08:45:28Z

Branch pushed to git repo; I updated commit sha1. New commits:

`2548e0e`	`trac #18774: internet`

sagetrac-git · 2015-06-25T08:45:28Z

Changed commit from 93801c8 to 2548e0e

sagetrac-git · 2015-06-25T10:47:57Z

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

`e977c17`	`trac #18774: internet`

sagetrac-git · 2015-06-25T10:47:57Z

Changed commit from 2548e0e to e977c17

dimpase · 2015-06-25T19:25:15Z

comment:21

Replying to @nathanncohen:

RTFM?

Always a pleasure to work with you dima

as we know, it's just an abbreviation of "Highly respected colleague, allow me most humbly
point to availability of material that might alleviate doubts you have hinted at
in your most valuable comments above"

:-)

nathanncohen · 2015-06-25T19:28:58Z

comment:22

as we know, it's just an abbreviation of [...]

I see. My life so far has been a lie.

Nathann

sagetrac-git · 2015-06-25T19:44:02Z

Branch pushed to git repo; I updated commit sha1. New commits:

`d07e879`	`say why J4 is not there`

sagetrac-git · 2015-06-25T19:44:02Z

Changed commit from e977c17 to d07e879

dimpase · 2015-06-25T20:13:08Z

comment:24

Nathann,
LGTM. Feel free to flip it to positive review if you're happy with my last commit.

dimpase · 2015-06-25T20:14:20Z

comment:25

Replying to @nathanncohen:

Then, there is stuff in $SAGE_LOCAL/gap

Yeah, I just figured this out offline. The thing is that you are not supposed to have writing access to SAGE_LOCAL/gap, so no information should be cached there. It should be done in ~/.sage/gap

so is there (where?) a bug?

nathanncohen · 2015-06-25T20:39:03Z

comment:26

so is there (where?) a bug?

Not sure. They may write to the system-wide repository if they can, and if they cannot then they write to the home gap directory.

nathanncohen · 2015-06-25T20:39:34Z

comment:27

LGTM. Feel free to flip it to positive review if you're happy with my last commit.

Works for me. Thanks!

Nathann

nathanncohen · 2015-06-25T20:39:34Z

Reviewer: Dima Pasechnik

vbraun · 2015-06-26T20:28:23Z

Changed branch from public/18774 to d07e879

nathanncohen mannequin added this to the sage-6.8 milestone Jun 23, 2015

nathanncohen mannequin added c: group theory labels Jun 23, 2015

nathanncohen mannequin added the s: needs review label Jun 23, 2015

dimpase added s: needs work and removed s: needs review labels Jun 23, 2015

nathanncohen mannequin added s: needs review and removed s: needs work labels Jun 23, 2015

fchapoton added s: needs work and removed s: needs review labels Jun 25, 2015

nathanncohen mannequin added s: needs review and removed s: needs work labels Jun 25, 2015

nathanncohen mannequin added s: positive review and removed s: needs review labels Jun 25, 2015

vbraun removed the s: positive review label Jun 26, 2015

vbraun closed this as completed in 347d797 Jun 26, 2015

Janko Groups and Livingstone graph #18774

Janko Groups and Livingstone graph #18774

Comments

nathanncohen mannequin commented Jun 23, 2015

nathanncohen mannequin commented Jun 23, 2015

nathanncohen mannequin commented Jun 23, 2015

nathanncohen mannequin commented Jun 23, 2015

sagetrac-git mannequin commented Jun 23, 2015

sagetrac-git mannequin commented Jun 23, 2015

dimpase commented Jun 23, 2015

sagetrac-git mannequin commented Jun 23, 2015

sagetrac-git mannequin commented Jun 23, 2015

nathanncohen mannequin commented Jun 23, 2015

fchapoton commented Jun 25, 2015

nathanncohen mannequin commented Jun 25, 2015

dimpase commented Jun 25, 2015

nathanncohen mannequin commented Jun 25, 2015

sagetrac-git mannequin commented Jun 25, 2015

sagetrac-git mannequin commented Jun 25, 2015

nathanncohen mannequin commented Jun 25, 2015

dimpase commented Jun 25, 2015

nathanncohen mannequin commented Jun 25, 2015

dimpase commented Jun 25, 2015

dimpase commented Jun 25, 2015

nathanncohen mannequin commented Jun 25, 2015

dimpase commented Jun 25, 2015

nathanncohen mannequin commented Jun 25, 2015

sagetrac-git mannequin commented Jun 25, 2015

sagetrac-git mannequin commented Jun 25, 2015

sagetrac-git mannequin commented Jun 25, 2015

sagetrac-git mannequin commented Jun 25, 2015

dimpase commented Jun 25, 2015

nathanncohen mannequin commented Jun 25, 2015

sagetrac-git mannequin commented Jun 25, 2015

sagetrac-git mannequin commented Jun 25, 2015

dimpase commented Jun 25, 2015

dimpase commented Jun 25, 2015

nathanncohen mannequin commented Jun 25, 2015

nathanncohen mannequin commented Jun 25, 2015

nathanncohen mannequin commented Jun 25, 2015

vbraun commented Jun 26, 2015