[GAP Forum] Source code of GAP

[Thomas Breuer]

Dear GAP Forum,

probably the question is about the GAP functions that compute
the irreducible characters of a given group,
not about the function 'CharacterTable'.

If yes then one should look for the methods for the function 'Irr',
for example using 'ApplicableMethod'.

Concerning the question about calculations with primitive roots
of unity, I would suggest to look at the chapters ``Cyclotomics''
and ``Abelian Number Fields'' of the GAP Reference Manual.
Also the paper cited as [Bre97] in this manual might be of interest.

All the best,
Thomas


On Sat, Apr 16, 2016 at 04:03:19PM +0430, fatemeh moftakhar wrote:
> Dear Forum
> 
> The command "Print(ff)" in GAP gives the code of the "ff" written in GAP.
> See for example the following command in GAP:
> gap> Print(Combinations);
> function ( arg )
>     local  combs, mset;
>     if Length( arg ) = 1  then
>         mset := ShallowCopy( arg[1] );
>         Sort( mset );
>         combs := CombinationsA( mset, 1, Length( mset ), [  ], 1 );
>     elif Length( arg ) = 2  then
>         mset := ShallowCopy( arg[1] );
>         Sort( mset );
>         combs := CombinationsK( mset, 1, Length( mset ), arg[2], [  ], 1 );
>     else
>         Error( "usage: Combinations( <mset> [, <k>] )" );
>     fi;
>     return combs;
> end
> 
> If I run the command "Print(CharacterTable)", then we can see the following
> GAP message:
> 
> gap> Print(CharacterTable);
> <Operation "CharacterTable">
> 
> Is it possible to find the GAP code for CharacterTable?
> 
> If no, is it possible to find the source of the program for calculating
> with primitive roots of unity in GAP?
> 
> finally where is the library of primitive roots of unity? For example I
> need to source program of GAP for computing E(8)-E(8)^3?
> 
> Best regards
> Fatemeh Moftakhar