Hi,
I have encountered a problem with using ROOT histograms for automatic
error propogation. The problem is that it does not take in to account
covariances, (which are normally 0 anyways). However, if a variable is
used twice in the same calculation, then it will have a covariance with
itself, which will not be taken into account.
ex. d(a+a)^2 = da^2 + da^2 + 2*Cov(a,a) = 4 da^2 = d(2a)^2
If you add these as two independent variables, then you will get the
wrong answer d(a+a)^2=2 da^2.
For example, there are repeated quantities in "show_dee{p,n}_asym.C"
Get{V,T}Asym().
For hydrogen, it looks like "show_ep_asym.C" is ok because it does the
errors by hand. Adrian, I remember you saying you used ROOT for error
propagation, so you may want to double-check your code too.
--chris
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