Hello Saad, Is the sum of squares output the cumulative SSE for each of the matrix elements? I need to know specifically what this SSE output is calculated from. I am trying to come up with errors on my eigenvalue estimates etc. Is there any way that I can see the source code for this? I'm assuming that this sum of square errors is only relevant for those who use multiple b-values or have multiple samples with the same b-value (otherwise we would get zero as SSE). I just need to know more clearly how this parameter is calculated from the tensor elements and output as a single SSE, otherwise I'll need to code my own software, and I really don't want to re-invent the wheel, if you know what I mean! Thanks, Megan