Dear alps team I am using fulldiag program for a system of 2 by 2 plaquette on fermion hubbard. Now I want it to solve for 3 particles and Sz = 0.5. When I display the values for Sz, it comes out to be 1.5. By hit and trial I come to know that alps only calculating Sz=0.5 for one particle only, when there are three particles Sz comes out to be 1.5. I definitely making some mistake in input file. I need a program that calculate 2 by 2 plaquette with fermion hubbard model with 3 particle and total spin 0.5 My program statements are as under but they are calculating 3 particles and total spin Sz= 1.5 which I even not mentioned. LATTICE_LIBRARY="/temp/ALPS/xml/lattices.xml"; MODEL_LIBRARY="/temp/ALPS/xml/models.xml"; MODEL="fermion Hubbard"; LATTICE="anisotropic square lattice"; MEASURE_AVERAGE[Density]="n" MEASURE_AVERAGE[Magnetization]="Sz" L=2; W=2; U=10.0; CONSERVED_QUANTUMNUMBERS="Sz,N"; Sz_total=0.5; N_Total=3; { t=1.0;} I am student and therefore something I make comments in hurry. Best Regards Khalid Loane