relax SVN archive

Docstring fix for the lib.dispersion.ns_matrices.rcpmg_2d() function.

Created the lib.dispersion.ns_matrices module.

This module contains a collection of functions for generating the relaxation matrices for the
numerical solutions to the Bloch-McConnell equations for relaxation dispersion.

The code comes from the 'fitting_main_kex.py' file attached to https://gna.org/task/?7712#comment3
(https://gna.org/support/download.php?file_id=18263).

Added a module docstring to lib.linear_algebra.matrix_power.

Added the missing mpower() function as lib.linear_algebra.matrix_power.square_matrix_power().

This is needed by the lib.dispersion.ns_2site_star module.

The function comes from the 'fitting_main_kex.py' file attached to comment 3 of task #7712
(https://gna.org/task/?7712#comment3, https://gna.org/support/download.php?file_id=18263).
The mpower() function was copied and modified to suite relax's coding conventions.

Added parameter conversions to go from pA and kex to kge and keg.

This is for the 'NS 2-site star' numerical model. The conversions have been added to the start of
the target function to minimise mathematical operations to speed up the code.

Better support for the R2A and R2B relaxation rate parameters in the relaxation dispersion analysis.

This includes a number of fixes to allow these two parameters to be handled correctly.

Fix for a fatal import bug introduced at r20280.

Added support for the 'NS 2-site star' model to the relax_disp.select_model user function back end.

This is the model of the numerical solution for the 2-site Bloch-McConnell equations using complex
conjugate matrices.

This commit follows step 6 of the relaxation dispersion model addition tutorial
(http://thread.gmane.org/gmane.science.nmr.relax.devel/3907).

Added support for the R2B parameter as required by the 'NS 2-site star' model.

This is the model of the numerical solution for the 2-site Bloch-McConnell equations using complex
conjugate matrices.

This commit follows step 5 of the relaxation dispersion model addition tutorial
(http://thread.gmane.org/gmane.science.nmr.relax.devel/3907).

Created the 'NS 2-site star' model target function.

This is the model of the numerical solution for the 2-site Bloch-McConnell equations using complex
conjugate matrices.

This commit follows step 4 of the relaxation dispersion model addition tutorial
(http://thread.gmane.org/gmane.science.nmr.relax.devel/3907).