Hi, I forgot to mention how I validated that the numeric model code in relax is functional and finding the correct result. I would have liked to compare the results with Flemming Hansen's CATIA program (http://www.biochem.ucl.ac.uk/hansen/catia/), but this relax export function is not implemented yet (unlike those for CMPGFit, ShereKhan, and NESSY). I therefore compared the results to those of the Carver and Richards (CR72) analytic model using Flemming Hansen's data from his 2008 J. Phys. Chem. B paper (http://dx.doi.org/10.1021/jp074793o). For residues 70 and 71, the analytic CR72 model results from the various programs and the numeric relax results are:
The CR72 model ============== Residue :70 ----------- Param relax NESSY CPMGFit ShereKhan R2 (500) 7.011 7.236 6.263 7.011 R2 (800) 9.465 10.027 6.263 9.465 pA 0.990 0.989 0.978 0.990 dw 5.577 5.373 0.937 5.577 kex 1765.993 1522.059 1.774 1765.988 chi2 18.450 7.701 65.237 18.450 Residue :71 ----------- Param relax NESSY CPMGFit ShereKhan R2 (500) 4.978 - 4.983 4.978 pA 0.997 - 0.994 0.997 dw 4.460 - 0.757 4.461 kex 1879.584 - 0.896 1879.618 chi2 1.379 - 1.382 1.379 The numeric models in relax =========================== Residue :70 ----------- Param NS 2-site 3D NS 2-site expanded NS 2-site star R2 (500) 6.996 6.996 6.996 R2 (800) 9.453 9.453 9.453 pA 0.990 0.990 0.990 dw 5.645 5.645 5.645 kex 1723.443 1723.443 1723.078 chi2 18.098 18.098 18.098 Residue :71 ----------- Param NS 2-site 3D NS 2-site expanded NS 2-site star R2 (500) 4.980 4.980 4.980 pA 0.997 0.997 0.997 dw 4.629 4.629 4.629 kex 1805.665 1805.676 1805.110 chi2 1.371 1.371 1.371 This comes from the test_suite/shared_data/dispersion/Hansen/software_comparison file. For these residues, you can see that the CR72 and numeric results are very similar. It could be hard to argue that they are statistically different. But this shows that the code is functioning perfectly. Regards, Edward On 23 July 2013 09:28, Edward d'Auvergne <[email protected]> wrote: > Hi, > > The 2-site numeric dispersion models for CPMG data are now fully functional > within relax! The following describes how these are implemented in relax > (to be permanently archived at > http://dir.gmane.org/gmane.science.nmr.relax.devel). I hope that you will > check all of this by running relax and seeing for yourself. I also have a > few questions below. Note that the code is in the relax_disp branch of the > source code repository and that there is no official release at > http://www.nmr-relax.com/download.html yet. > > I have documented the numeric models now present in relax in Chapter 10 of > the user manual. I have compiled the current manual for the branch and > uploaded it to http://download.gna.org/relax/manual/relax_disp_manual.pdf. > Please have a look and see what you think. The text is extremely minimal > and needs to be expanded. If you have any suggestions or additional > material (equations, figures, etc., and in LaTeX preferably), it would be > happily accepted. For example equations for the matrices and the > propagation used. The aim is to be a complete stand-alone relaxation > dispersion reference for the users, pointing them to all the relevant > literature at all possible points. Cheers! > > As a summary, from the relax_disp.select_model user function description, > the numeric models are: > > 'NS 2-site 3D': The reduced numerical solution for the 2-site > Bloch-McConnell equations using 3D magnetisation vectors whereby the > simplification R20A = R20B is assumed. Its parameters are {R20, ..., pA, > dw, kex}. > > 'NS 2-site 3D full': The full numerical solution for the 2-site > Bloch-McConnell equations using 3D magnetisation vectors. Its parameters > are {R20A, R20B, ..., pA, dw, kex}. > > 'NS 2-site star': The reduced numerical solution for the 2-site > Bloch-McConnell equations using complex conjugate matrices whereby the > simplification R20A = R20B is assumed. It has the parameters {R20, ..., pA, > dw, kex}. > > 'NS 2-site star full': The full numerical solution for the 2-site > Bloch-McConnell equations using complex conjugate matrices with parameters > {R20A, R20B, ..., pA, dw, kex}. > > 'NS 2-site expanded': The numerical solution for the 2-site > Bloch-McConnell equations expanded using Maple by Nikolai Skrynnikov. It > has the parameters {R20, ..., pA, dw, kex}. > > I would be interested to hear if you have suggestions for saner model names. > > In the auto-analysis in relax - the blackbox analysis script to make the > lives of users extremely easy - the *full models are not turned on by > default. If curious, you can see auto-analysis script in the file > auto_analyses/relax_disp.py. The auto-analysis script is normally hidden > from the user. Also, please run the relax GUI with: > > $ relax --gui > > and start the relaxation dispersion analysis to see how it is implemented. > Note that the auto-analyses are used for the operation of all GUI analyses. > Using scripts, the relax user is free to do anything they wish and implement > any protocol they can imagine (if useful for other users, these can then be > converted into an auto-analysis). > > Part of the auto-analysis that I have implemented is the concept of using > optimised parameters from a simpler or equivalent model to speed up > optimisation by avoiding an expensive grid search. For the 'full' models > above, I use the parameters of the simpler model and start with R20A = R20B > = R20. Then, during optimisation, R20A and R20B diverge. > > For the model equivalence, this is a bit different. I use the optimised > parameter values from the analytic Carver and Richards model (CR72) as the > starting parameters for the 'NS 2-site 3D', 'NS 2-site star' and 'NS 2-site > expanded' models. This avoids the grid search and really speeds up the > optimisation by orders of magnitude. It can be done because the CR72 > results are often very similar to the numeric results. And even a failed > CR72 solution is close enough to the minima to be used as a starting point > for the numeric models. > > I have a few other implementation questions, but I'll send these in a > different message for saner threads in the mailing list archives. > > Cheers, > > Edward > > > P. S. Actually, I might take some of this text into the relax manual :) _______________________________________________ relax (http://www.nmr-relax.com) This is the relax-devel 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-devel
