-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hello Ian,
I dare say that the goal is to get phases which match as good as possible with what is inside the crystal. If this coincides with maximising the likelihood, why don't we run refinement until the LL stabilises? @Garib: I have seen runs where Refmac actually does stop "prematurely", i.e. before the number of cycles set in the input script. It seems that it stops when LL does not drop between two cycles, but according to Ian this would be the point to reach. My question: does this indeed provide the best interpretable map (be it cheating or not)? Cheers, Tim On 08/24/2011 05:36 PM, Ian Tickle wrote: > Hi Tim > > The answer is a definite NO, the goal of refinement is to maximise the > likelihood from the working set and the restraints. It is definitely not to > optimise Rfree or LLfree. The correct value of the latter is whatever you > get at convergence of refinement, i.e. at maximum of the likelihood, > anything else is 'cheating'. > > Cheers > > -- Ian > > On Wed, Aug 24, 2011 at 4:24 PM, Tim Gruene <t...@shelx.uni-ac.gwdg.de> wrote: > > Dear all, > > especially at the beginning of model building and/or at low resolution > both Rfree and "-LL free" as reported in the refmac logfile show a > minimum at a some cycle before rising again. > > I am certainly not the only one tempted to first run refmac with a large > number of refinement cycles, determine that minimum and rerun refmac > with ncyc set to that minimum. > > Of course I want the resulting model and phases/map to be as close to > the what's in the crystal as possible in order to facilitate model > building. > > Is it therefore good practice to interrupt refmac wherever it finds a > minimum (if so, the minimum w.r.t. which number reported in the log-file)? > > Thanks for everyone's opinion and experience, > > Tim > >> - -- - -- Dr Tim Gruene Institut fuer anorganische Chemie Tammannstr. 4 D-37077 Goettingen GPG Key ID = A46BEE1A -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iD8DBQFOVgiBUxlJ7aRr7hoRAq+dAKDj2B6iUMD7C4uu8UMznTlKoclYzACdF8nP Q6DmIFGPcfoP6xbJRwooWWI= =7r5T -----END PGP SIGNATURE-----
