Made the function use the new multidimensional R_mat matrix.
Systemtest: test_tp02_data_to_ns_r1rho_2site still passes.
Task #7807 (https://gna.org/task/index.php?7807): Speed-up of dispersion models for Clustered analysis.
Authored by: tlinnet 2014-06-19
Parent: [r24168]
Child: [r24170]