GAP 4.8.9 installation with standard packages -- copy to your CoCalc project to get it
#############################################################################
##
## HomalgExternalRing.gi HomalgToCAS package Mohamed Barakat
##
## Copyright 2007-2008 Lehrstuhl B für Mathematik, RWTH Aachen
##
## Implementation stuff for external rings.
##
#############################################################################
##
DeclareRepresentation( "IshomalgExternalRingObjectRep",
IshomalgExternalObjectRep,
[ ] );
## <#GAPDoc Label="IsHomalgExternalRingRep">
## <ManSection>
## <Filt Type="Representation" Arg="R" Name="IsHomalgExternalRingRep"/>
## <Returns><C>true</C> or <C>false</C></Returns>
## <Description>
## The internal representation of &homalg; rings. <P/>
## (It is a representation of the &GAP; category <C>IsHomalgRing</C>.)
## </Description>
## </ManSection>
## <#/GAPDoc>
##
DeclareRepresentation( "IsHomalgExternalRingRep",
IsHomalgRing and IsHomalgRingOrFinitelyPresentedModuleRep,
[ "ring", "homalgTable" ] );
## <#GAPDoc Label="IsHomalgExternalRingElementRep">
## <ManSection>
## <Filt Type="Representation" Arg="r" Name="IsHomalgExternalRingElementRep"/>
## <Returns><C>true</C> or <C>false</C></Returns>
## <Description>
## The representation of elements of external &homalg; rings. <P/>
## (It is a representation of the &GAP; category <Ref Filt="IsHomalgRingElement"/>.)
## </Description>
## </ManSection>
## <#/GAPDoc>
##
DeclareRepresentation( "IsHomalgExternalRingElementRep",
IsHomalgRingElement,
[ ] );
# a new subrepresentation of the representation IsContainerForWeakPointersRep:
DeclareRepresentation( "IsContainerForWeakPointersOnHomalgExternalRingsRep",
IsContainerForWeakPointersRep,
[ "weak_pointers", "streams", "counter", "deleted" ] );
## <#GAPDoc Label="IsHomalgExternalMatrixRep">
## <ManSection>
## <Filt Type="Representation" Arg="A" Name="IsHomalgExternalMatrixRep"/>
## <Returns><C>true</C> or <C>false</C></Returns>
## <Description>
## The external representation of &homalg; matrices. <P/>
## (It is a representation of the &GAP; category <Ref Filt="IsHomalgMatrix"/>.)
## </Description>
## </ManSection>
## <#/GAPDoc>
##
DeclareRepresentation( "IsHomalgExternalMatrixRep",
IsHomalgMatrix,
[ ] );
####################################
#
# families and types:
#
####################################
# a new type:
BindGlobal( "TheTypeHomalgExternalRing",
NewType( TheFamilyOfHomalgRings,
IsHomalgExternalRingRep ) );
# three new types:
BindGlobal( "TheTypeHomalgExternalRingElement",
NewType( TheFamilyOfHomalgRingElements,
IsHomalgExternalRingElementRep ) );
BindGlobal( "TheTypeHomalgExternalMatrix",
NewType( TheFamilyOfHomalgMatrices,
IsHomalgExternalMatrixRep ) );
# a new family:
BindGlobal( "TheFamilyOfContainersForWeakPointersOnHomalgExternalRings",
NewFamily( "TheFamilyOfContainersForWeakPointersOnHomalgExternalRings" ) );
# a new type:
BindGlobal( "TheTypeContainerForWeakPointersOnHomalgExternalRings",
NewType( TheFamilyOfContainersForWeakPointersOnHomalgExternalRings,
IsContainerForWeakPointersOnHomalgExternalRingsRep ) );
####################################
#
# methods for operations:
#
####################################
##
InstallMethod( homalgPointer,
"for homalg external rings",
[ IsHomalgExternalRingRep ],
function( R )
return homalgPointer( R!.ring );
end );
##
InstallMethod( homalgExternalCASystem,
"for homalg external rings",
[ IsHomalgExternalRingRep ],
function( R )
return homalgExternalCASystem( R!.ring );
end );
##
InstallMethod( homalgExternalCASystemVersion,
"for homalg external rings",
[ IsHomalgExternalRingRep ],
function( R )
return homalgExternalCASystemVersion( R!.ring );
end );
##
InstallMethod( homalgStream,
"for homalg external rings",
[ IsHomalgExternalRingRep ],
function( R )
return homalgStream( R!.ring );
end );
##
InstallMethod( homalgExternalCASystemPID,
"for homalg external rings",
[ IsHomalgExternalRingRep ],
function( R )
return homalgExternalCASystemPID( R!.ring );
end );
##
InstallMethod( homalgLastWarning,
"for homalg external rings",
[ IsHomalgExternalRingRep ],
function( R )
homalgLastWarning( R!.ring );
end );
##
InstallMethod( homalgNrOfWarnings,
"for homalg external rings",
[ IsHomalgExternalRingRep ],
function( R )
return homalgNrOfWarnings( R!.ring );
end );
##
InstallMethod( homalgPointer,
"for homalg external ring elements",
[ IsHomalgExternalRingElementRep ],
function( r )
local e;
e := EvalRingElement( r ); ## here we must evaluate
if IshomalgExternalObjectRep( e ) then
return homalgPointer( e );
elif IsString( e ) or IsFunction( e ) then
return e;
fi;
Error( "the value of EvalRingElement of an external ring element must be either an external object, a string, or a function\n" );
end );
##
InstallMethod( homalgExternalCASystem,
"for homalg external ring elements",
[ IsHomalgExternalRingElementRep ],
function( r )
local R;
R := HomalgRing( r );
if IsHomalgExternalRingRep( R ) then
return homalgExternalCASystem( R ); ## avoid evaluating the ring element
else
return homalgExternalCASystem( EvalRingElement( r ) );
fi;
end );
##
InstallMethod( homalgExternalCASystemVersion,
"for homalg external ring elements",
[ IsHomalgExternalRingElementRep ],
function( r )
local R;
R := HomalgRing( r );
if IsHomalgExternalRingRep( R ) then
return homalgExternalCASystemVersion( R ); ## avoid evaluating the ring element
else
return homalgExternalCASystemVersion( EvalRingElement( r ) );
fi;
end );
##
InstallMethod( homalgStream,
"for homalg external ring elements",
[ IsHomalgExternalRingElementRep ],
function( r )
local R;
R := HomalgRing( r );
if IsHomalgExternalRingRep( R ) then
return homalgStream( R ); ## avoid evaluating the ring element
else
return homalgStream( EvalRingElement( r ) );
fi;
end );
##
InstallMethod( homalgExternalCASystemPID,
"for homalg external ring elements",
[ IsHomalgExternalRingElementRep ],
function( r )
local R;
R := HomalgRing( r );
if IsHomalgExternalRingRep( R ) then
return homalgExternalCASystemPID( R ); ## avoid evaluating the ring element
else
return homalgExternalCASystemPID( EvalRingElement( r ) );
fi;
end );
##
InstallMethod( String,
"for homalg external ring elements",
[ IsHomalgExternalRingElementRep ],
Name );
##
InstallMethod( homalgSetName,
"for homalg external ring elements",
[ IsHomalgExternalRingElementRep, IsString, IsHomalgExternalRingRep ],
function( r, name, R )
SetName( r, homalgSendBlocking( [ r ], "need_output", HOMALG_IO.Pictograms.homalgSetName ) );
end );
##
InstallMethod( homalgSetName,
"for homalg external ring elements",
[ IsHomalgExternalRingElementRep, IsString ],
function( r, name )
homalgSetName( r, name, HomalgRing( r ) );
end );
##
InstallMethod( \=,
"for homalg external ring elements",
[ IsHomalgExternalRingElementRep, IsHomalgExternalRingElementRep ],
function( r1, r2 )
if not IsIdenticalObj( homalgStream( r1 ), homalgStream( r2 ) ) then
return false;
elif EvalRingElement( r1 ) = EvalRingElement( r2 ) then
return true;
fi;
TryNextMethod( );
end );
##
InstallGlobalFunction( LetWeakPointerListOnExternalObjectsContainRingCreationNumbers,
function( R )
local container;
container := homalgStream( R ).homalgExternalObjectsPointingToVariables;
if not IsBound( container!.ring_creation_numbers ) then
container!.ring_creation_numbers := [ ];
fi;
end );
##
InstallGlobalFunction( AppendTohomalgTablesOfCreatedExternalRings,
function( homalgTableForCAS, filter )
local weak_pointers, i, R;
if not IsBound( HOMALG_MATRICES.ContainerForWeakPointersOnHomalgExternalRings ) then
return;
fi;
weak_pointers := HOMALG_MATRICES.ContainerForWeakPointersOnHomalgExternalRings!.weak_pointers;
for i in [ 1 .. Length( weak_pointers ) ] do
R := ElmWPObj( weak_pointers, i );
if R <> fail then
if filter( R ) then
AppendToAhomalgTable( homalgTable( R ), homalgTableForCAS );
fi;
fi;
od;
end );
##
InstallMethod( \/,
"for a homalg external ring element and a homalg external ring",
[ IsHomalgExternalRingElementRep, IsHomalgExternalRingRep ],
function( r, R )
local RP;
RP := homalgTable( R );
if not IsIdenticalObj( HomalgRing( r ), R ) and
IsHomalgExternalRingRep( HomalgRing( r ) ) and
IsIdenticalObj( homalgStream( HomalgRing( r ) ), homalgStream( R ) ) and
IsBound( RP!.CopyElement ) then ## make a "copy" over a different ring
return HomalgExternalRingElement( RP!.CopyElement( r, R ), R );
fi;
TryNextMethod( );
end );
####################################
#
# constructor functions and methods:
#
####################################
##
InstallGlobalFunction( CreateHomalgExternalRing,
function( arg )
local nargs, r, l, HOMALG_IO_CAS, nar, stream, ring_type, ar, R, container, weak_pointers, deleted, streams;
nargs := Length( arg );
if nargs < 2 then
Error( "expecting a ring object or arguments to pass to homalgSendBlocking as the first argument and a ring type as the second argument\n" );
fi;
r := arg[1];
if IsList( r ) then
l := 4;
HOMALG_IO_CAS := arg[3];
nar := Length( r );
## check whether the last argument already has a stream pointing to a running
## instance of the external CAS
if nargs > 1 then
if IsRecord( r[nar] ) and IsBound( r[nar].lines ) and IsBound( r[nar].pid ) then
stream := r[nar];
elif IshomalgExternalObjectRep( r[nar] ) or IsHomalgExternalRingRep( r[nar] ) then
stream := homalgStream( r[nar] );
fi;
fi;
## if no such stream is found in the last argument, start and initialize
## a new instance of the external CAS
if not IsBound( stream ) then
if IsString( HOMALG_IO_CAS ) and IsBound( ValueGlobal( HOMALG_IO_CAS ).common_stream ) then
HOMALG_IO_CAS := ValueGlobal( HOMALG_IO_CAS );
## use the stream stored in HOMALG_IO_CAS to
## avoid launching a new instance of the external CAS
## (suggested by Oleksandr Motsak)
stream := HOMALG_IO_CAS.common_stream;
elif IsRecord( HOMALG_IO_CAS ) and IsBound( HOMALG_IO_CAS.common_stream ) then
## use the stream stored in HOMALG_IO_CAS to
## avoid launching a new instance of the external CAS
## (suggested by Oleksandr Motsak)
stream := HOMALG_IO_CAS.common_stream;
else
stream := LaunchCAS( HOMALG_IO_CAS );
if IsString( HOMALG_IO_CAS ) then
HOMALG_IO_CAS := ValueGlobal( HOMALG_IO_CAS );
fi;
if IsBound( stream.init_string ) then
## send the init string
homalgSendBlocking( stream.init_string, "need_command", stream, HOMALG_IO.Pictograms.initialize );
fi;
## initialize the macros
if IsBound( stream.InitializeCASMacros ) then
stream.InitializeCASMacros( stream );
fi;
## store stream as a common stream for later rings to
## avoid launching a new instance of the external CAS
## (suggested by Oleksandr Motsak)
if ( IsBound( HOMALG_IO_CAS.use_common_stream ) and
HOMALG_IO_CAS.use_common_stream = true ) or
( not ( IsBound( HOMALG_IO_CAS.use_common_stream ) and
HOMALG_IO_CAS.use_common_stream = false ) and
IsBound( HOMALG_IO.use_common_stream ) and
HOMALG_IO.use_common_stream = true ) then
HOMALG_IO_CAS.common_stream := stream;
fi;
fi;
else
r := r{[ 1 .. nar - 1 ]};
fi;
Append( r, [ stream, HOMALG_IO.Pictograms.CreateHomalgRing ] );
r := CallFuncList( homalgSendBlocking, r );
else
l := 3;
fi;
ring_type := arg[2];
ar := [ r, [ ring_type, TheTypeHomalgExternalMatrix ], HomalgExternalRingElement ];
ar := Concatenation( ar, arg{[ l .. nargs ]} );
## create the external ring
R := CallFuncList( CreateHomalgRing, ar );
## for the view methods:
## <A matrix over an external ring>
R!.description := "n external";
if not IsBound( HOMALG_MATRICES.ContainerForWeakPointersOnHomalgExternalRings ) then
HOMALG_MATRICES.ContainerForWeakPointersOnHomalgExternalRings :=
ContainerForWeakPointers( TheTypeContainerForWeakPointersOnHomalgExternalRings, [ "streams", [ ] ] );
fi;
container := HOMALG_MATRICES.ContainerForWeakPointersOnHomalgExternalRings;
weak_pointers := container!.weak_pointers;
l := container!.counter;
deleted := Filtered( [ 1 .. l ], i -> not IsBoundElmWPObj( weak_pointers, i ) );
container!.deleted := deleted;
l := l + 1;
container!.counter := l;
SetElmWPObj( weak_pointers, l, R );
streams := container!.streams;
if not homalgExternalCASystemPID( R ) in List( streams, s -> s.pid ) then
Add( streams, homalgStream( R ) );
fi;
return R;
end );
##
InstallGlobalFunction( HomalgExternalRingElement,
function( arg )
local nargs, el, pointer, ring, cas, ar, properties, r;
nargs := Length( arg );
if nargs = 0 then
Error( "empty input\n" );
fi;
if IsHomalgExternalRingElementRep( arg[1] ) then
el := arg[1];
## rebuild an external ring element
## only if it does not already contain a ring and
## if a ring is provided as a second argument
if not IsBound( el!.ring ) and
nargs > 1 and IsHomalgRing( arg[2] ) then
pointer := homalgPointer( el );
ring := arg[2];
if IsFunction( pointer ) then
pointer := pointer( ring );
fi;
cas := homalgExternalCASystem( ring );
ar := [ pointer, cas, ring ];
properties := KnownTruePropertiesOfObject( el );
Append( ar, List( properties, ValueGlobal ) );
return CallFuncList( HomalgExternalRingElement, ar );
fi;
## otherwise simply return it
return el;
fi;
properties := [ ];
for ar in arg{[ 2 .. nargs ]} do
if not IsBound( cas ) and IsString( ar ) then
cas := ar;
elif not IsBound( ring ) and IsHomalgExternalRingRep( ar ) then
ring := ar;
cas := homalgExternalCASystem( ring );
elif IsFilter( ar ) then
Add( properties, ar );
else
Error( "this argument (now assigned to ar) should be in { IsString, IsHomalgExternalRingRep, IsFilter }\n" );
fi;
od;
if IsString( arg[1] ) then
pointer := function( R )
local RP;
RP := homalgTable( R );
if IsBound( RP!.RingElement ) then
return RP!.RingElement( R )( arg[1] );
else
return arg[1];
fi;
end;
else
pointer := arg[1];
fi;
if IsBound( ring ) then
if IsFunction( pointer ) then
pointer := pointer( ring );
fi;
r := rec( cas := cas, ring := ring );
else
r := rec( cas := cas );
fi;
## Objectify:
ObjectifyWithAttributes(
r, TheTypeHomalgExternalRingElement,
EvalRingElement, pointer );
if properties <> [ ] then
for ar in properties do
Setter( ar )( r, true );
od;
fi;
return r;
end );
##
InstallMethod( \in,
"for a finite field element and an external ring",
[ IsRingElement, IsHomalgExternalRingRep ],
function( r, R )
if not IsHomalgExternalRingElementRep( r ) then
return false;
elif not IsIdenticalObj( HomalgRing( r ), R ) then
return false;
fi;
return true;
end );
##
InstallMethod( \/,
"for a finite field element and an external ring",
[ IsFFE, IsHomalgExternalRingRep ],
function( r, R )
local k, c, d, z;
if HasCoefficientsRing( R ) then
k := CoefficientsRing( R );
else
k := R;
fi;
if not ( HasCharacteristic( k ) and HasDegreeOverPrimeField( k ) ) then
TryNextMethod( );
fi;
c := Characteristic( k );
d := DegreeOverPrimeField( k );
if d = 1 then
return HomalgRingElement( String( Int( r ) ), R );
fi;
if not IsBound( k!.NameOfPrimitiveElement ) then
Error( "no NameOfPrimitiveElement bound\n" );
fi;
z := k!.NameOfPrimitiveElement;
return HomalgRingElement( FFEToString( r, c, d, z ), R );
end );
####################################
#
# View, Print, and Display methods:
#
####################################
##
InstallMethod( ViewObj,
"for homalg external ring objects",
[ IshomalgExternalRingObjectRep ],
function( o )
Print( "<A homalg external ring object residing in the CAS " );
Print( homalgExternalCASystem( o ), ">" );
end );
##
InstallMethod( ViewObj,
"for homalg external rings",
[ IsHomalgExternalRingRep ],
function( o )
local ring, stream, display_color, esc;
ring := RingName( o );
stream := homalgStream( o );
if IsBound( stream.color_display ) then
display_color := stream.color_display;
esc := "\033[0m";
else
display_color := "";
## esc must be empty, otherwise GAPDoc's TestManualExamples will complain
esc := "";
fi;
Print( display_color, ring, esc );
end );
##
InstallMethod( Display,
"for homalg external rings",
[ IsHomalgExternalRingRep ],
function( o )
Print( "<An external " );
if IsPreHomalgRing( o ) then
Print( "pre-homalg " );
fi;
Print( "ring" );
if not ( IsBound( HOMALG_IO.suppress_CAS ) and HOMALG_IO.suppress_CAS = true ) then
Print( " residing in the CAS " );
if IsBound( homalgStream( o ).color_display ) then
Print( "\033[1m" );
fi;
Print( homalgExternalCASystem( o ) );
if not ( IsBound( HOMALG_IO.suppress_PID ) and HOMALG_IO.suppress_PID = true ) then
Print( "\033[0m running with pid ", homalgExternalCASystemPID( o ) );
fi;
fi;
Print( ">", "\n" );
end );
##
InstallMethod( Name,
"for homalg external ring elements",
[ IsHomalgExternalRingElementRep ],
function( o )
local pointer;
pointer := homalgPointer( o );
if not IsFunction( pointer ) then
homalgSetName( o, pointer );
return Name( o );
fi;
TryNextMethod( );
end );
##
InstallMethod( ViewObj,
"for containers of weak pointers on homalg external rings",
[ IsContainerForWeakPointersOnHomalgExternalRingsRep ],
function( o )
local del;
del := Length( o!.deleted );
Print( "<A container of weak pointers on homalg external rings: active = ", o!.counter - del, ", deleted = ", del, ">" );
end );
##
InstallMethod( Display,
"for containers of weak pointers on homalg external rings",
[ IsContainerForWeakPointersOnHomalgExternalRingsRep ],
function( o )
local weak_pointers;
weak_pointers := o!.weak_pointers;
Print( List( [ 1 .. LengthWPObj( weak_pointers ) ], function( i ) if IsBoundElmWPObj( weak_pointers, i ) then return i; else return 0; fi; end ), "\n" );
end );