gap> polytope:=CoxeterComplex_alt(D,5);;
gap> R:=FreeGResolution(polytope,5);
Resolution of length 5 in characteristic 0 for &lt;matrix group with 
8 generators> . 
No contracting homotopy available. 

gap> C:=TensorWithIntegers(R);
Chain complex of length 5 in characteristic 0 . 

gap> Homology(C,4);
[ 2, 2, 2, 2 ]
