Hi Jacob

It's not the cosine of the phase error, it's the *expectation* of the cosine of the phase error, obtained from the probability density function of the phase error.  Important words often get omitted in casual conversation!

Cheers

-- Ian


On 26 January 2016 at 16:52, Keller, Jacob <[log in to unmask]> wrote:
Dear Crystallographers,

I've wondered this for a while, but have not tracked down the answer yet: FOM is defined as the cosine of the phase error. To determine the phase error, it would seem necessary to know the model phases and also the true phases. But if we know the true phases, then...? Accordingly, there must be some way to estimate the phase error without knowing the true phases--how is that done?

JPK

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Jacob Pearson Keller, PhD
Looger Lab/HHMI Janelia Research Campus
19700 Helix Dr, Ashburn, VA 20147
email: [log in to unmask]
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