== References ==
NThe function uses an explicit matrix that contains relaxation, exchange and chemical shift terms. It does the 180deg pulses in the CPMG train. The approach of Bloch-McConnell can be found in chapter 3.1 of Palmer, A. G. Chem Rev 2004, 104, 3623-3640. This function was written, initially in MATLAB, in 2010. This is the model of the numerical solution for the 2-site Bloch-McConnell equations. It originates as optimization function number 1 from the fitting_main_kex.py script from Mathilde Lescanne, Paul Schanda, and Dominique Marion (see U{http://thread.gmane.org/Agmane.science.nmr.relax.devel/4138}, U{https://gna.org/task/?7712#comment2} and U{https://gna.org/support/download.php?file_id=18262}).
== Related models ==