There may be a problem with sparsediag (my previous coding error notwithstanding).
Here is the parameter file used for both sparsediag and fulldiag
LATTICE_LIBRARY = "/usr/local/ALPS/lib/xml/lattices.xml"; LATTICE = "inhomogeneous simple cubic lattice"; MODEL_LIBRARY= "/usr/local/ALPS/lib/xml/models.xml"; MODEL = "alternative fermion Hubbard"; CONSERVED_QUANTUMNUMBERS="N,Sz"; MEASURE_LOCAL[Local charge density]=n; t = 1.0; L = 2; U = 9.0; N_total = 4; Sz_total = 0; TRANSLATION_SYMMETRY = false; {DISORDERSEED = 11138; mu = -6.0*(random()-0.5);}
Here is the relevant portion of the task1.out file generated by sparsediag - the densities are all zero, but the ground state energy is correct (see below).
<EIGENVALUES number="1"> -11.43877071841712 </EIGENVALUES> <EIGENSTATES number="1"> <EIGENSTATE number="0"> <SCALAR_AVERAGE name="Energy"><MEAN>-11.43877071841712</MEAN></SCALAR_AVERAGE> <VECTOR_AVERAGE name="Local charge density"> <SCALAR_AVERAGE indexvalue="( 0,0,0 )"><MEAN>0</MEAN></SCALAR_AVERAGE> <SCALAR_AVERAGE indexvalue="( 0,0,1 )"><MEAN>0</MEAN></SCALAR_AVERAGE> <SCALAR_AVERAGE indexvalue="( 0,1,0 )"><MEAN>0</MEAN></SCALAR_AVERAGE> <SCALAR_AVERAGE indexvalue="( 0,1,1 )"><MEAN>0</MEAN></SCALAR_AVERAGE> <SCALAR_AVERAGE indexvalue="( 1,0,0 )"><MEAN>0</MEAN></SCALAR_AVERAGE> <SCALAR_AVERAGE indexvalue="( 1,0,1 )"><MEAN>0</MEAN></SCALAR_AVERAGE> <SCALAR_AVERAGE indexvalue="( 1,1,0 )"><MEAN>0</MEAN></SCALAR_AVERAGE> <SCALAR_AVERAGE indexvalue="( 1,1,1 )"><MEAN>0</MEAN></SCALAR_AVERAGE> </VECTOR_AVERAGE>
Here is a portion of the output from fulldiag - same energy as sparsediag, but now the local charge densities are non zero.
<EIGENVALUES number="784"> -11.43877071841714 </EIGENVALUES> ... <EIGENSTATE number="0"> <SCALAR_AVERAGE name="Energy"><MEAN>-11.43877071841714</MEAN></SCALAR_AVERAGE> <VECTOR_AVERAGE name="Local charge density"> <SCALAR_AVERAGE indexvalue="( 0,0,0 )"><MEAN>0.3727847497057824</MEAN></SCALAR_AVERAGE> <SCALAR_AVERAGE indexvalue="( 0,0,1 )"><MEAN>0.8699453754269064</MEAN></SCALAR_AVERAGE> <SCALAR_AVERAGE indexvalue="( 0,1,0 )"><MEAN>0.4528964351309576</MEAN></SCALAR_AVERAGE> <SCALAR_AVERAGE indexvalue="( 0,1,1 )"><MEAN>0.7330138222807983</MEAN></SCALAR_AVERAGE> <SCALAR_AVERAGE indexvalue="( 1,0,0 )"><MEAN>0.6288755119873222</MEAN></SCALAR_AVERAGE> <SCALAR_AVERAGE indexvalue="( 1,0,1 )"><MEAN>0.1885341339328754</MEAN></SCALAR_AVERAGE> <SCALAR_AVERAGE indexvalue="( 1,1,0 )"><MEAN>0.3029849265253151</MEAN></SCALAR_AVERAGE> <SCALAR_AVERAGE indexvalue="( 1,1,1 )"><MEAN>0.4509650450100266</MEAN></SCALAR_AVERAGE> </VECTOR_AVERAGE>