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Implement DFS #47

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8 changes: 0 additions & 8 deletions gap/LINS.gd
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Original file line number Diff line number Diff line change
Expand Up @@ -264,11 +264,3 @@ DeclareGlobalFunction( "LINS_FindPModules" );
DeclareGlobalFunction( "LINS_MustCheckP" );

DeclareGlobalFunction( "LINS_FindIntersections" );


#############################################################################
## helper function
#############################################################################

DeclareGlobalFunction( "LINS_IsSubgroupFp" );
DeclareGlobalFunction( "LINS_SetParent" );
1 change: 1 addition & 0 deletions gap/LINS.gi
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Expand Up @@ -184,6 +184,7 @@ function(gr)
fi;
end);


#############################################################################
####=====================================================================####
##
Expand Down
11 changes: 8 additions & 3 deletions gap/addGroup.gi
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Expand Up @@ -23,7 +23,7 @@
## We need coset tables of both `H` and `G` in the parent `P`.
#############################################################################

InstallGlobalFunction(LINS_IsSubgroupFp, function(G, H)
BindGlobal("LINS_IsSubgroupFp", function(G, H)
local word;

for word in AugmentedCosetTableInWholeGroup(H).primaryGeneratorWords do
Expand All @@ -44,7 +44,7 @@ end);
## Sets parent and attributes for normal subgroup `H` of `G`.
#############################################################################

InstallGlobalFunction(LINS_SetParent,
BindGlobal("LINS_SetParent",
function(H, G)
SetParent(H, G);
SetIsNormalInParent(H, true);
Expand Down Expand Up @@ -135,8 +135,8 @@ InstallGlobalFunction(LINS_AddGroup, function(gr, H, Supers, test, opts)
local
G, # group: located in the root node
# of LINS graph `gr`.
rH, # LINS node: containing `H`
n, # pos-int: index bound of LINS graph `gr`.
rH, # LINS node: containing `H`
allSupergroups, # [LINS node]: supergroups of `rH`
allSubgroups, # [LINS node]: subgroups of `rH`
pos, # pos-int: position of level at index $[G : H]$
Expand All @@ -146,6 +146,11 @@ InstallGlobalFunction(LINS_AddGroup, function(gr, H, Supers, test, opts)
K; # group: located in node `rK`

G := Grp(LinsRoot(gr));

if opts.DoSetParent then
LINS_SetParent(H, G);
fi;

rH := LinsNode(H, Index(G, H));

# Search for correct level
Expand Down
82 changes: 28 additions & 54 deletions gap/findTQuotients.gi
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Expand Up @@ -13,50 +13,6 @@
#############################################################################


BindGlobal("Terminate", MakeImmutable("Terminate"));

# Terminate, if we found sufficient enough groups
# true, if K is a new group
# false, if K was already found beforehand
BindGlobal("LINS_AddGroup_Caller",
function(gr, rH, K, opts, infoText)
local
G, # group: located in the root node of the LINS graph `gr`.
n, # pos-int: index bound of LINS graph `gr`.
data, # tuple: [`rK`, `isNew`]
rK, # LINS node: containing group `K`
isNew; # boolean: whether the group `K` is new in `gr`

G := Grp(LinsRoot(gr));
n := IndexBound(gr);

if opts.DoSetParent then
LINS_SetParent(K, G);
fi;

if Index(G, K) <= n then
data := LINS_AddGroup(gr, K, [rH], true, opts);
rK := data[1];
isNew := data[2];

if isNew then
Info(InfoLINS, 3, LINS_tab3, infoText,
"Found new normal subgroup ", LINS_red, "K = ", K, LINS_reset,
" of index ", LINS_red, Index(G, K), LINS_reset, ".");

if opts.DoTerminate(gr, rH, rK) then
gr!.TerminatedUnder := rH;
gr!.TerminatedAt := rK;
return Terminate;
else
return true;
fi;
fi;
fi;

return false;
end);

#############################################################################
## LINS_FindTQuotients
#############################################################################
Expand Down Expand Up @@ -149,8 +105,10 @@ InstallGlobalFunction( LINS_FindTQuotients, function(gr, opts)
homs, # [hom]: list of homomorphisms into `Q`
hom, # hom: loop var, homomorphism in `L` from `H` into `Q`
K, # group: normal subgroup of `G` (with Q-quotient)
data, # state: bool or Terminate
nrFound; # pos-int: number of newly found normal subgroups
rK, # LINS node: containing `K`
isNew, # boolean: whether the group `K` is new in `gr`
nrFound, # pos-int: number of newly found normal subgroups
data; # tuple: [`rK`, `isNew`]

# Initialize data from input.
rG := LinsRoot(gr);
Expand Down Expand Up @@ -189,11 +147,19 @@ InstallGlobalFunction( LINS_FindTQuotients, function(gr, opts)
for L in LL do
if Position(I, Index(G, L)) <> fail then
K := Core(G, L);
data := LINS_AddGroup_Caller(gr, rG, K, opts, "");
if data = true then
data := LINS_AddGroup(gr, K, [rG], true, opts);
rK := data[1];
isNew := data[2];
if isNew then
nrFound := nrFound + 1;
elif data = Terminate then
return [true, nrFound + 1];
Info(InfoLINS, 3, LINS_tab3,
"Found new normal subgroup ", LINS_red, "K = ", K, LINS_reset,
" of index ", LINS_red, Index(G, K), LINS_reset, ".");
fi;
if isNew and opts.DoTerminate(gr, rG, rK) then
gr!.TerminatedUnder := rG;
gr!.TerminatedAt := rK;
return [true, nrFound];
fi;
fi;
od;
Expand All @@ -203,11 +169,19 @@ InstallGlobalFunction( LINS_FindTQuotients, function(gr, opts)
homs := GQuotients(H, Q);
for hom in homs do
K := Image(iso, Kernel(hom));
data := LINS_AddGroup_Caller(gr, rG, K, opts, "");
if data = true then
data := LINS_AddGroup(gr, K, [rG], true, opts);
rK := data[1];
isNew := data[2];
if isNew then
nrFound := nrFound + 1;
elif data = Terminate then
return [true, nrFound + 1];
Info(InfoLINS, 3, LINS_tab3,
"Found new normal subgroup ", LINS_red, "K = ", K, LINS_reset,
" of index ", LINS_red, Index(G, K), LINS_reset, ".");
fi;
if isNew and opts.DoTerminate(gr, rG, rK) then
gr!.TerminatedUnder := rG;
gr!.TerminatedAt := rK;
return [true, nrFound];
fi;
od;
od;
Expand Down