> < ^ From:

> < ^ Subject:

GAP forum:

On Sat, Jun 16, 2001 at 05:06:39PM +0200, Pamb wrote:

> I had asked GAP Forum the follwoing question

>

> > Here is my question:

> >

> > I have a set S with 30 elements, together with a symmetric binary relation R, which

> > holds between some of the elements of S. I would like to find out all the

> > permutations of S which preserve the relation R, in the following precise sense

> > f: S to S, f bijection satisfying "a R b if and only if f(a) R f(b)".

> >

> > Is there any program in GAP that would allow me to do that?

> >

>

> and have received the answer that grape would do it. I went to a computer with gap

> installed on it, read the book containing the documentation on it, ...

But you have missed the bit, that said, do:

gap> RequirePackage("grape");

Loading GRAPE 4.1 (GRaph Algorithms using PErmutation groups),

by L.H.Soicher@qmw.ac.uk.

true

In the Reference Manual that is covered in Section 73.3 "Loading a Share

Package" (in a general way).

If the `RequirePackage' command does not reply as above, you will need to

install GRAPE first. If this is the case, you can download the share package

from one of the GAP mirrors e.g. http://www.math.rwth-aachen.de/~GAP/

(which should be your closest).

Look for the `Share Packages' link under `Get GAP' on that page. Follow

that link and you should find `GRAPE' the first package listed. To

install the package in your own directory see the Reference Manual

Setion 73.2 "Installing a Share Package in your home directory" and

follow GRAPE's README.

The documentation for GRAPE is in its doc/ (.dvi, .ps formats) or htm/

(HTML format) directory. If you didn't have to install it yourself but

have no idea of the path of the gap4r2/pkg/grape directory on your system,

GRAPE's HTML documentation is also on the web (found by following the trail

of links already mentioned - look for the link `GRAPE manual'). You can

also read GRAPE's documentation from within GAP once GRAPE is installed.

Try:

gap> ?EdgeOrbitsGraph

and for more info. on how to read documentation from within GAP, try:

gap> ?help

(Of course, `gap> ' is the GAP prompt, in all the examples above ... you

don't type that.)

Finally, queries such as the one currently being answered are more properly

dealt with by `gap-trouble' (i.e. just replace `gap-forum' by `gap-trouble'

in the address instead) ... though your initial query was correctly directed

to `gap-forum'.

Regards, Greg Gamble ___________________________________________________________________ Greg Gamble __________________ mailto:gregg@math.rwth-aachen.de Lehrstuhl D fuer Mathematik Tel: +49 241 804545 Templergraben 64 52062 Aachen, Germany http://www.math.rwth-aachen.de/~Greg.Gamble ___________________________________________________________________

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