Dear all, I am refining a protein structure using phenix.refine, when i tried to use optimize_wxc, optimize_wxu It always crashes and gives following error. May anybody can explain what is the problem?? Traceback (most recent call last): File "/public/xtal/phenix/phenix-1.3b/phenix-1.3b/phenix/phenix/command_line/refine.py", line 5, in <module> command_line.run(command_name="phenix.refine", args=sys.argv[1:]) File "/public/xtal/phenix/phenix-1.3b/phenix-1.3b/phenix/phenix/refinement/command_line.py", line 78, in run call_back_after_monitor_collect=call_back_after_monitor_collect) File "/public/xtal/phenix/phenix-1.3b/phenix-1.3b/phenix/phenix/refinement/driver.py", line 1308, in run log = log) File "/public/xtal/phenix/phenix-1.3b/phenix-1.3b/phenix/phenix/refinement/strategies.py", line 642, in refinement_machine log = log) File "/public/xtal/phenix/phenix-1.3b/phenix-1.3b/phenix/phenix/refinement/weight_xray_chem.py", line 327, in __init__ self.wxc_optimization() File "/public/xtal/phenix/phenix-1.3b/phenix-1.3b/phenix/phenix/refinement/weight_xray_chem.py", line 450, in wxc_optimization rw, rf, b, a, a_xc = self.wx_opt_helper(w = wxc_scale_0 * wxc, sites=True) File "/public/xtal/phenix/phenix-1.3b/phenix-1.3b/phenix/phenix/refinement/weight_xray_chem.py", line 387, in wx_opt_helper verbose = 0) TypeError: __init__() takes at least 5 non-keyword arguments (3 given) Thanks in advance. Yusuf