[Ifeffit] polarization in Artemis
bravel at bnl.gov
Sun May 24 13:50:39 CDT 2015
Everything in the discussion between Eugenio and Matt is stuff I agree
with, except ...
When I rewrote Artemis, one of the motivations was that I wanted to
write my own pathfinder rather than to continue using the one in Feff.
My main motivation was fuzzy degeneracy
(http://bruceravel.github.io/demeter/artug/extended/fuzzy.html) plus I
wanted to correct a few other things I saw as shortcomings.
When I was writing it years ago, I didn't immediately see an easy way to
consider polarization correctly while also doing fuzzy degeneracy
correctly. I have since figured that out, but years went by and only
one person ever asked me about polarized feff calculations in Artemis.
So I never implemented it.
It's a funny thing, when you wait for a bus, none comes, then two show
up at once. A month ago, I was asked about polarization in Artemis, and
now Eugenio brings it up!
Polarization works (although it needs testing) in the very latest code
in github. But I did that work since the last time I built a Windows
installer. Ellipticity does not yet work (in Artemis -- it works just
fine in Feff, but Artemis does not deliver the ellipticity-dependent
calculation to the user).
Anyway, I will try to find a few hours this week to build a new Windows
installer, which will included the ability to consider linear polarization.
> Artemis used to make this very easy (sum paths without fitting), but
> I don't recall how to do this in the latest version.
Still is easy. Well, I think it is. YMMV :)
Bruce Ravel ------------------------------------ bravel at bnl.gov
National Institute of Standards and Technology
Synchrotron Science Group at NSLS-II
Upton NY, 11973
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