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Rewrite IsAspherical #158

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Merged
grahamknockillaree merged 1 commit into from
Aug 18, 2026
Merged

Rewrite IsAspherical #158

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77 changes: 26 additions & 51 deletions lib/Polymake/aspherical.gi
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Original file line number Diff line number Diff line change
Expand Up @@ -18,20 +18,10 @@ local
EqualitiesVec,
InEqualities,
InEqSizes,
Polymake,
tmpdir, tmpin, tmpodir, tmpout,
TestFeasible,
L,r,
AppendTo, PrintTo,
R,Redges,V,ii,bol, sm, i,x,row,n,m,M;

AppendTo:=HAP_AppendTo;
PrintTo:=HAP_PrintTo;

tmpdir := DirectoryTemporary();;
tmpin:=Filename( tmpdir , "tmpIn.log" );
tmpodir := DirectoryTemporary();;
tmpout:=Filename( tmpdir , "tmpOut.log" );

if Length(arg)=2 then F:=arg[1]; Frels:=arg[2]; fi;
if Length(arg)=1 then
G:=arg[1];
Expand Down Expand Up @@ -155,51 +145,36 @@ fi;
od;

#####################################################################
Polymake:=function()
local V, i, x, input;

AppendTo(tmpin,"EQUATIONS","\n");

for i in [1..Length(EqualitiesMat)] do
AppendTo(tmpin,-EqualitiesVec[i]," ");
for x in [1..Length(EqualitiesMat[1])] do
AppendTo(tmpin,EqualitiesMat[i][x]," ");
od;
AppendTo(tmpin,"\n");
od;

AppendTo(tmpin,"\n","INEQUALITIES","\n");

for i in [1..Length(InEqualities)] do
AppendTo(tmpin,-2," ");
for x in [1..Length(InEqualities[1])] do
AppendTo(tmpin,InEqualities[i][x]," ");
od;
AppendTo(tmpin,"\n");
od;

for i in [1..Length(InEqualities[1])] do
AppendTo(tmpin,0," ");
for x in [1..Length(InEqualities[1])] do
if i=x then AppendTo(tmpin,1," ");
else AppendTo(tmpin,0," "); fi;
od;
AppendTo(tmpin,"\n");
od;

Exec(Concatenation(POLYMAKE_COMMAND, " ", "'my $c=load(\"",tmpin,"\"); print $c-> FEASIBLE;' > ",tmpout));
Exec(Concatenation("rm ",tmpin));
input := InputTextFile(tmpout);
x:=ReadLine(input);
Exec(Concatenation("rm ",tmpout));
TestFeasible:=function()
local poly, n, equations, inequalities;

n:=Length(InEqualities[1]);

equations:=List([1..Length(EqualitiesMat)],
i->Concatenation([-EqualitiesVec[i]],EqualitiesMat[i]));

# every generator is asked for at least 2, and for at least 0 individually
inequalities:=Concatenation(
List(InEqualities,row->Concatenation([-2],row)),
List(IdentityMat(n),row->Concatenation([0],row)));

poly:=CreatePolymakeObject();
if Length(equations)>0 then
# polymaking 0.8 has no method taking a matrix for a section it does not
# know by name, so EQUATIONS has to go through a string; the rest of this
# uses the higher level methods, which both versions provide
AppendToPolymakeObject(poly,
ConvertMatrixToPolymakeString("EQUATIONS",equations));
fi;
AppendInequalitiesToPolymakeObject(poly,inequalities);

return x;
return Polymake(poly,"FEASIBLE");
end;
#####################################################################

x:= Polymake();
x:= TestFeasible();

if x="true" then
if x=true then
Print("Presentation is aspherical.\n\n"); return true;
else
Print("Test inconclusive.\n\n");
Expand Down
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