[GAP Forum] Re: [GAP Support] Question

[David Joyner]

A. Sadrodini:

Maybe this is what you meant:

F:=function(d,q)
local sl,gsl,i,g,gens;
 sl:=SL(d,q);
 gsl:=GeneratorsOfGroup(sl);
 gens:=[];
 for g in gsl do
   Add(gens,BlockMatrix([[1,1,g],[2,2,TransposedMat(g^-1)]],2,2));
 od;
 i:=IdentityMat(d,GF(q));
 Add (gens,BlockMatrix([[1,2,i],[2,1,i]],2,2));
 return Subgroup(GL(2*d,q),gens);
end;

Alexander Konovalov already mentioned some of the errors in the program you
had. Here is an example of the above program:

gap> gens:=GeneratorsOfGroup(F(2,2));;
gap> Display(gens[1]);
 1 1 . .
 . 1 . .
 . . 1 .
 . . 1 1
gap> Size(F(2,2));
12
gap> StructureDescription(F(2,2));
"D12"

Hope this helps.

- David

+++++++++++++++++++++++++++++++++++++++++

ASADR wrote:

>-----Original Message-----
>From: "ASADR" <ASADR at modares.ac.ir>
>To: support at gap-system.org
>Date: Sat, 05 Aug 2006 11:47:03 +0330
>Subject: Question
>
>
>Dear Sir\Madam, 
>I hope you are fine.
> 
>I am a Ph.D. student in pure mathematics at TMU, Tehran-Iran.
>I am interested in finite groups and I do my computations with GAP.
>when I use the following code:
> 
>  
>
>>F:=function(d,q)
>> sl:=SL(d,q);
>> gsl:=GeneratorsOfGroup(sl);
>> gens:=[];
>> for g in gsl do
>> Add(gens,MatrixByBlockMatrix(BlockMatrix([1,1,g],[2,2,TransposedMat(g^ 
>>    
>>
>-1))]],2,2)
>  
>
>> od;
>>i:=IdentityMat(d,GF(q));
>>Add (gens,MatrixByBlockMatix(BlockMatrix([1,2,i],[2,1,i))]],2,2)
>>return Subgroup(GL(2*d,q),gens);
>>end;
>>    
>>
> 
>I get the error(in 2-line) "syntax error: warning:unbounded global variable"
> 
>I would appreciate  to resolve this problem.
>I would be gratefull to receive any other information on that topic, too. 
>
>Yours Sincerely,
>A. Sadrodini
>_______________________________________________
>Support mailing list
>Support at gap-system.org
>http://mail.gap-system.org/mailman/listinfo/support
>
>  
>