I'm trying to calculate the separability of 22 sets of roi points that were input from ASCII. When I select all of these I get an error saying 'TRIQL: too many iterations in tqli. The result may be invalid' and if I try to select only a few I get an error saying 'Singular value encountered in calculation for ROI' for each region. and the results show zero for divergence.   Has anyone come across these errors or know why they're occuring?