@arokem, @ecaruyer, @mdesco I am not familiar with this function but I can see that it has been used in dipy/bin/fit_tensor by @MrBago. Because this is the first example that people will read we absolutely need to make sure that the example reads smoothly. For example this reordering thing in line 183 is a bit puzzling and I don't know why it was not used in fit_tensor.