Dear Chris, Thanks for the helpful suggestion. I have tried as you suggested to repeat steps 2-4 from estimated tm and then from best-fit tm. Since estimated tm I used is from modelfree (which is very good) I actually got converged results immediately. However, I noticed that a subtle difference in tm caused Chi-square significantly different. Of cause, other parameters are also different. The question is how to judge which set of data is more accurate (based on Chi-square??).
Best wishes, Hongyan Quoting Chris MacRaild <[EMAIL PROTECTED]>: > Hi Hongyan, > > relax is designed to be completely flexible in the way you perform your > analysis, allowing for the procedure to be tailored to the system at > hand, or for new proceedures to be developed. One procedure that I can > recomend which is somewhat similar to the one you outline is as follows: > > 1. estimate tm > 2. fit each residue to dynamic models > 3. select best model > 4. fit tm and dynamic parameters simultaneously > 5. repeat steps 2-4 starting from best-fit tm value. Continue until > results converge > 6. repeat steps 2-5 for each diffusion model (isotropic, axially > symetric and anisotropic) > 7. select best diffusion model > 8. Monte Carlo simulations (error analysis) > > As you note, Monte Carlo simulations over all parameters will be very > slow. This is why I recommend only performing the error analysis at the > end of the whole proceedure. I some cases it may be necessary to perform > the Monte Carlo simulations over only the dynamic parameters (ie. with > diffusion tensor fixed) in order to improve efficiency. > > There has been some discussion of this and other analysis proceedures on > this list before. The thread that starts here: > > https://mail.gna.org/public/relax-users/2006-10/msg00007.html > > is worth a look. > > Chris Dr. Hongyan Li Department of Chemistry The University of Hong Kong Pokfulam Road Hong Kong _______________________________________________ relax (http://nmr-relax.com) This is the relax-users mailing list [email protected] To unsubscribe from this list, get a password reminder, or change your subscription options, visit the list information page at https://mail.gna.org/listinfo/relax-users
