<!-- ------------------------------------------------------------------- -->
<!-- -->
<!-- others.xml Utils documentation Stefan Kohl -->
<!-- Sebastian Gutsche -->
<!-- Max Horn -->
<!-- Copyright (C) 2015-2025, The GAP Group -->
<!-- -->
<!-- ------------------------------------------------------------------- -->
<?
xml version=
"1.0" encoding=
"UTF-8"?>
<Chapter Label=
"chap-others">
<Heading>Various other functions</Heading>
<Section Label=
"sec-log2html">
<Heading>File operations</Heading>
<ManSection>
<Func Name=
"Log2HTML"
Arg=
"filename"/>
<Description>
This function has been transferred from package &RCWA;.
<P/>
This function converts the &GAP; logfile <File>filename</File> to
HTML.
It appears that the logfile should be in your current directory.
The extension of the input file must be <File>*.log</File>.
The name of the output file is the same as the one of the input file
except that the extension <File>*.log</File> is replaced by <File>*.
html</File>.
There is a sample CSS file in <File>utils/doc/gaplog.css</File>,
which you can adjust to your taste.
<P/>
</Description>
</ManSection>
<P/>
<Example>
<![
CDATA[
gap> LogTo(
"triv.log" );
gap> a := 33^5;
39135393
gap> LogTo();
gap> Log2HTML(
"triv.log" );
]]>
</Example>
</Section>
<Section Label=
"sec-latex">
<Heading>&LaTeX; strings</Heading>
<ManSection>
<Func Name=
"IntOrOnfinityToLaTeX"
Arg=
"n"/>
<Description>
This function has been transferred from package &ResClasses;.
<P/>
<C>IntOrInfinityToLaTeX(n)</C> returns the &LaTeX; string for <A>n</A>.
<P/>
</Description>
</ManSection>
<P/>
<Example>
<![
CDATA[
gap> IntOrInfinityToLaTeX( 10^3 );
"1000"
gap> IntOrInfinityToLaTeX( infinity );
"\\infty"
]]>
</Example>
<ManSection>
<Func Name=
"LaTeXStringFactorsInt"
Arg=
"n"/>
<Description>
This function has been transferred from package &RCWA;.
<P/>
It returns the prime factorization of the integer <M>n</M> as a string in
&LaTeX; format.
<P/>
</Description>
</ManSection>
<P/>
<Example>
<![
CDATA[
gap> LaTeXStringFactorsInt( Factorial(12) );
"2^{10} \\cdot 3^5 \\cdot 5^2 \\cdot 7 \\cdot 11"
]]>
</Example>
</Section>
<Section Label=
"sec-magma">
<Heading>Conversion to &Magma; strings</Heading>
<ManSection>
<Func Name=
"ConvertToMagmaInputString"
Arg=
"arg"/>
<Description>
The function <C>ConvertToMagmaInputString( obj [, str] )</C>
attempts to output a string <C>s</C> which can be read into
&Magma; <Cite Key=
"MAGMA" />
so as to produce the same group in that computer algebra system.
In the second form the user specifies the name of the resulting object,
so that the output string has the form <C>
"str := ..."</C>.
<P/>
When <C>obj</C> is a permutation group, the operation
<C>PermGroupToMagmaFormat(obj)</C> is called.
<Index>PermGroupToMagmaFormat</Index>
This function has been taken from <File>other.gi</File> in the main library
where it was called <C>MagmaInputString</C>.
<P/>
When <C>obj</C> is a pc-group, the operation
<C>PcGroupToMagmaFormat(obj)</C> is called.
<Index>PcGroupToMagmaFormat</Index>
This function was private code of Max Horn.
<P/>
When <C>obj</C> is a matrix group over a finite field,
the operation <C>MatrixGroupToMagmaFormat(obj)</C> is called.
<Index>MatrixGroupToMagmaFormat</Index>
This function is a modification of private code of Frank Lübeck.
<P/>
Hopefully code for other types of group will be added in due course.
<P/>
These functions should be considered <E>experimental</E>,
and more testing is desirable.
<P/>
</Description>
</ManSection>
<P/>
<Example>
<![
CDATA[
gap> ## permutation groups
gap> ConvertToMagmaInputString( Group( (1,2,3,4,5), (3,4,5) ) );
"PermutationGroup<5|(1,2,3,4,5),\n(3,4,5)>;\n"
gap> ConvertToMagmaInputString( Group( (1,2,3,4,5) ),
"c5" );
"c5 := PermutationGroup<5|(1,2,3,4,5)>;\n"
gap> ## pc-group
gap> ConvertToMagmaInputString( DihedralGroup( IsPcGroup, 10 ) );
"PolycyclicGroup< f1,f2 |\nf1^2,\nf2^5,\nf2^f1 = f2^4\n>;\n"
gap> ## fp-group
gap> F2 := FreeGroup( 2 );;
gap> f := F2.1;; g := F2.2;;
gap> relq8 := [ f^4, g^4, f*g*f*g^-1, f^2*g^2 ];;
gap> q8 := F2/relq8;;
gap> ConvertToMagmaInputString( q8 );
no conversion function yet available for fp-groups
fail
gap> ## matrix group
gap> M := GL(2,5);; Size(M);
480
gap> s1 := ConvertToMagmaInputString( M );
"F := GF(5);\nP := GL(2,F);\ngens := [\nP![2,0,0,1],\nP![4,1,4,0]\n];\nsub
gens>;\n"
gap> Print( s1 );
F := GF(5);
P := GL(2,F);
gens := [
P![2,0,0,1],
P![4,1,4,0]
];
sub<P | gens>;
gap> n1 := [ [ Z(9)^0, Z(9)^0 ], [ Z(9)^0, Z(9) ] ];;
gap> n2 := [ [ Z(9)^0, Z(9)^3 ], [ Z(9)^4, Z(9)^2 ] ];;
gap> N := Group( n1, n2 );; Size( N );
5760
gap> s2 := ConvertToMagmaInputString( N, "gpN" );;
gap> Print( s2 );
F := GF(3^2);
P := GL(2,F);
w := PrimitiveElement(F);
gens := [
P![ 1, 1, 1,w^1],
P![ 1,w^3, 2,w^2]
];
gpN := sub<P | gens>;
]]>
</Example>
</Section>
</Chapter>
