View source for NS CPMG 2-site expanded

The relaxation dispersion model for the numeric solution (NS) to the Bloch-McConnell equations for [[SQ CPMG-type data]].  This uses the Maple expanded and fast equations from Nikolai Skrynnikov.  The model is labelled as '''NS CPMG 2-site expanded''' in [[Relaxation dispersion citation for relax|relax]].

This type of model can be called '''silico''' derived, as it is a computer-assisted derivation for the equivalent computations, of the much more expensive numerical matrix-form.

This function is exact, just as the explicit Bloch-McConnell numerical treatments.  It comes from a Maple derivation based on the Bloch-McConnell equations.  It is much faster than the numerical Bloch-McConnell solution.  It was derived by Nikolai Skrynnikov and is provided with his permission.

== Parameters ==

The NS CPMG 2-site expanded model has the parameters {{{:R2zero}}, ..., {{:pA}}, {{:Deltaomega}}, {{:kex}}}.

== Code ==

The library code:  {{relax url|path=lib/dispersion/ns_cpmg_2site_expanded.py}}

== Reference ==

The reference for the NS CPMG 2-site expanded model is:

* {{#lst:Citations|Tollinger01}}

== Code origin ==

The code originates as optimization function number 5 from the fitting_main_kex.py script from Mathilde Lescanne, Paul Schanda, and Dominique Marion (see the [http://thread.gmane.org/gmane.science.nmr.relax.devel/4138 mailing list discussion], the {{gna task link|7712|comment=2|text=relax task with attached code}} and the [https://gna.org/support/download.php?file_id=18262 file]).

Links to the copyright licensing agreements from all authors are:

* [http://article.gmane.org/gmane.science.nmr.relax.devel/4279 Nikolai Skrynnikov],
* [http://article.gmane.org/gmane.science.nmr.relax.devel/4276 Martin Tollinger],
* [http://article.gmane.org/gmane.science.nmr.relax.devel/4271 Paul Schanda],
* [http://article.gmane.org/gmane.science.nmr.relax.devel/4138 Mathilde Lescanne],
* [http://article.gmane.org/gmane.science.nmr.relax.devel/4157 Dominique Marion].

== Links ==

The [[Relaxation dispersion citation for relax|implementation of the NS CPMG 2-site expanded model in relax]] can be seen in the:
* [http://www.nmr-relax.com/manual/The_NS_2_site_expanded_CPMG_model.html relax manual], 
* [http://www.nmr-relax.com/api/3.1/lib.dispersion.ns_cpmg_2site_expanded-module.html API documentation],
* [http://www.nmr-relax.com/analyses/relaxation_dispersion.html#NS_CPMG_2-site_expanded relaxation dispersion page of the relax website].

== See also ==
[[Category:Models]]
[[Category:Dispersion models]]
[[Category:Relaxation dispersion analysis]]