Positive and negative minos errors are swaped in toys fit results
When fitting toys with toys/fit_toys.py
and then loading the results with load_toy_fits
from toys/tools
all the X_err_plus
errors are negative while the X_err_minus
are positive. From a quick look at toys.tools.load_toy_fits
the problem is not here, so it's probably at the time of writting the fit results to hdf
.