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#############################################################################
##
## This file is part of GAP, a system for computational discrete algebra.
## This file's authors include Thomas Breuer, Martin Schönert, Frank Celler.
##
## Copyright of GAP belongs to its developers, whose names are too numerous
## to list here. Please refer to the COPYRIGHT file for details.
##
## SPDX-License-Identifier: GPL-2.0-or-later
##
## This file contains
## 1. the design of families of general mappings
#############################################################################
##
#M FamiliesOfGeneralMappingsAndRanges( <Fam> )
##
InstallMethod( FamiliesOfGeneralMappingsAndRanges,
"for a family (return empty list)",
true,
[ IsFamily ], 0,
function(fam)
return LockAndMigrateObj(WeakPointerObj( [] ), GENERAL_MAPPING_REGION);
end);
#############################################################################
##
#F GeneralMappingsFamily( <famsourceelms>, <famrangeelms> )
##
InstallGlobalFunction( GeneralMappingsFamily, function( FS, FR )
local info, i, len, entry, Fam, freepos;
atomic readwrite GENERAL_MAPPING_REGION do
# Check whether this family was already constructed.
info:= FamiliesOfGeneralMappingsAndRanges( FS );
len:= LengthWPObj( info );
for i in [ 1.. len+1 ] do
entry:=ElmWPObj( info, i );
if entry=fail then
if not IsBound( freepos ) then
freepos:= i;
fi;
elif IsIdenticalObj( FamilyRange(entry), FR ) then
return entry;
fi;
od;
# Construct the family.
if CanEasilyCompareElementsFamily(FR)
and CanEasilyCompareElementsFamily(FS) then
Fam:= NewFamily( "GeneralMappingsFamily", IsGeneralMapping ,
CanEasilyCompareElements,
CanEasilyCompareElements);
else
Fam:= NewFamily( "GeneralMappingsFamily", IsGeneralMapping );
fi;
SetFamilyRange( Fam, FR );
SetFamilySource( Fam, FS );
# Store the family in free spot.
SetElmWPObj( info, freepos, Fam );
# Return the family.
return Fam;
od;
end );
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