Problem

This was reported by arya sukumaran on the diffpy-users, so please refer there for the full thread, but Simon reproduced a bug somewhat similar when working with a student, so this may actually be a bug: "There may be a bug.  I was working with a student and we found that to get the the errors to show up you had to do some kind of dance of switching parameters on then off, but not all off.  Strange.  I will post an issue and we can maybe try and figure it out."

Proposed solution

• reproduce the bug and fix it so that uncertainties appear as a matter of course in the results file.
• Make sure that the same one is downloaded for consistency (there is no reason to believe this is not the case, but.....)

One upgrade could be to rerun the fit on the Nyquist grid to get the uncertainties, or to have a button that can be selected to compute uncertainties. Note that uncertainties computed on grids other than the Nyquist are generally wrong.