Warning about ufloat objects with std_dev==0 as of uncertainties release 3.2.3

[thehrh]

With the most recent uncertainties release, this warning regularly appears and needs investigation.

See lmfit/uncertainties#300 (further discussion referred to therein) and https://github.com/lmfit/uncertainties/releases/tag/3.2.3.

[thehrh]

It seems a ufloat with zero uncertainty is only created by our config parser, namely when a string does not contain "+/-":

pisa/pisa/utils/config_parser.py

Line 344 in ec3affe

value = ufloat(float(value), 0)

.

Follow-up questions: Do we rely on these being ufloats down the line? Can we just create a regular float object instead? Do we try to suppress the warnings?