Hi, Dear all, I was using phenix.refine to refine the structure. Once I turned on optimize_wxc w/o optimize_wxu, the job failed with the following message. ----------xray term weight optimization (wxc)---------- Traceback (most recent call last): File "/Application/phenix/phenix-1.3b-rc6/phenix/phenix/command_line/refine.py", line 5, in <module> command_line.run(command_name="phenix.refine", args=sys.argv[1:]) File "/Application/phenix/phenix-1.3b-rc6/phenix/phenix/refinement/command_line.py", line 82, in run call_back_after_monitor_collect=call_back_after_monitor_collect) File "/Application/phenix/phenix-1.3b-rc6/phenix/phenix/refinement/driver.py", line 1143, in run call_back_after_monitor_collect = call_back_after_monitor_collect) File "/Application/phenix/phenix-1.3b-rc6/phenix/phenix/refinement/strategies.py", line 449, in refinement_machine log = log) File "/Application/phenix/phenix-1.3b-rc6/phenix/phenix/refinement/weight_xray_chem.py", line 256, in __init__ self.wxc_optimization() File "/Application/phenix/phenix-1.3b-rc6/phenix/phenix/refinement/weight_xray_chem.py", line 511, in wxc_optimization wxc = self.holder.wxc The phenix I used is the latest version, 1.3b rc6. The platform is intel-linux-2.6 redhat-e4. Python is 2.4.2 Could anyone please tell me what the problem is? Thank you very much! -- Best Regards, Shi Jiahai