[phenixbb] phenix and weak data

[Ed Pozharski]

On Fri, 2012-12-07 at 13:57 -0800, Pavel Afonine wrote:
> > I had always assumed that experimental sigmas were somehow lumped
> into the alpha and beta parameters (esp. given your discussion in
> section 2.3).  In principle they could be, right?
> 
> Yes, they could be. 

I would like clarification on this.  I was under impression (some of it
formed by reading the papers) that it is not that experimental errors
are "lumped" into beta, it is simply assumed that they are much smaller
than "model error" and are therefore simply ignored because they are
negligible.

Alpha/beta are calculated in individual resolution shells.  How can you
"lump" experimental variance that varies by two orders of magnitude for
individual reflections into a single parameter?

I also wonder if introducing experimental uncertainty into Lunin's ML
target is even possible without fundamentally altering it.  It would
remove ability to obtain analytical expressions for alpha/beta (also
known as D/sigma_wc**2) as far as I can see.  Which is the hallmark of
this version of maximum likelihood target.  

Cheers,

Ed.

-- 
Bullseye!  Excellent shot, Maurice.
                                  Julian, King of Lemurs.