Hi all, Emanuele, I use to save the eigenvalues of the reduced density matrix too. The way I do it is to pipe the standard output to a grep command, then to a file. I'm using a GNU/Linux and there the grep command can "include" or "exclude" patterns it reads from a file. You know, the standard output for VERBOSE=1 includes too much information then I select what patterns I want to keep: SWEEP, ITERATION, RHO and I save that patterns in a file "patterns_file" (one per line) in the same directory where I put the python file with the definitions then, I run alpspython defs.py | grep -f patterns > rdm.log Then, the file rdm.log keeps the information about what SWEEP and what ITERATION has that list of RHO EIGENVALUES. Maybe it is not the best way to do it, I would like to know if someone else find another way to do it. Ciao Giovanni