Hi, I am wondering if authors of refinement programs would like to consider putting on their users wish list the ability of refinement programs to automatically terminate once the refinement has reached convergence. Various refinement metrics such as R factors, CC or RMS values typically will reach a plateau once the refinement of a macromolecular structure with X-ray or EM-data has converged and further macro-cycles of refinement will no longer improve the structure. The default number of macro-cycles in programs such as Phenix-refine and Refmac are probably sensible for most cases but in some cases it would be nice if the programs automatically extended the number of macro-cycles as needed (or decreased the number).
The user can of course examine log files from refinement themselves and decide whether to continue refinement. But since starting a new session of refinement appears to always create an initial fluctuation in the refinement metrics before they align with the values of the last macro-cycles in the previous refinement session, the user is compelled to do at least, say 3 or more macrocycles in addition to whatever may be needed for reaching convergence. I guess it would therefore be more efficient if this was implemented directly in the refinement programs and presented as an option for the user to choose. There could be cases where alternate conformations of a structure will repeatedly be oscillating in and out of density thus causing the refinement metrics also to oscillate. Hopefully such cases could be covered by gauging the level of fluctuations of the refinement metrics and terminate the refinement accordingly. Many thanks, Robert ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 This message was issued to members of www.jiscmail.ac.uk/CCP4BB, a mailing list hosted by www.jiscmail.ac.uk, terms & conditions are available at https://www.jiscmail.ac.uk/policyandsecurity/
