with(coxeter):
read maxset;
read chrome;

# Find colorings for the F4 graph.
# Select good inner products (assuming r1<>r2);

gip:=proc(i,j,pr) local c;
  c:=iprod(pr[i],pr[j]);
  if c>0 then NULL elif c<0 then {i,j}
    elif iprod(pr[i],pr[i])<>iprod(pr[j],pr[j]) then {i,j} fi
end:

interface(quiet=true);
pr:=pos_roots(F4): X:={$1..nops(pr)};
G:={seq(seq(gip(j,i,pr),j=1..i-1),i=1..nops(pr))}: nops(G);
mis:=maxset(G,X): nops(mis);
st:=time(): chrome(mis,X,4,'c'), c, .733*(time()-st);
st:=time(): chrome(mis,X,5,'c'), c, .733*(time()-st);
interface(quiet=false);
quit;