The k_BA and k_AB rates are used to simplify the Psi calculation, dropping from 3 to 2
multiplications and removing a squaring operation. The Dpos and Dneg value calculations have been
simplified to drop one multiplication operation. And the calculation of eta_scale / cpmg_frqs now
only occurs once rather than twice.
Using the disp_profile_all.py script, the speed ups for these two models are:
100 single spins analysis:
CR72: 1.608+/-0.025 -> 1.552+/-0.028, 1.036x faster.
CR72 full: 1.795+/-0.043 -> 1.705+/-0.024, 1.053x faster.
Cluster of 100 spins analysis:
CR72: 0.109+/-0.001 -> 0.107+/-0.001, 1.026x faster.
CR72 full: 0.114+/-0.004 -> 0.110+/-0.001, 1.034x faster.
