[ALPS-users] The problem of measuring stiffness in QMC with defining lattice using graph

Dear All, For the lattice in alps, we can use <LATTICES> <GRAPH>, in which can define an arbitrary lattice. However I find when I use this way, the stiffness measured in QMC is always zero. I wonder how to fix it. Thank you very much. Sincerely, Huaiming Guo