On 07/24/2016 03:55 AM, Samy Ould-Chikh wrote:
I have some issue to import a file in Athena: just a simple x-y column (.txt 
attached with this email).

Ti K-edge.
Data range in the file  : 4916.30 up to 5436.88 eV.
Issue: only data up to 5260 eV are imported (see screenshot: bug-importation).

Version: Demeter 0.9.24
System: Windows 7 Professional SP1

Well, I hope it's just not me not being able to find a proper way to import the 
file...

I have a hard time imagining the need for an XAFS scan with 12000 data points. That will usually provides a point density that about an order of magnitude below the core-hole lifetime, maybe 2. In your case, it corresponds to about 0.04 eV steps, which seems silly to me. While I'm quite open to being convinced otherwise, I cannot believe that setting up a scan this way is actually necessary.

But, more to the point, I think it is very unprofessional of the beamline staff to send you home with data in a format that is so hard to use.

Athena does a pretty good job of importing data in all the crazy-ass formats that beamlines around the world use. But it's not really fair to expect that she can handle anything you can throw at her. If a beamline presents data in a format that is not easy to interpret, it should provide tools for converting the data to a format that can reasonably be interpreted.

In your case, the beamline should provide you with a way to rebin the data either onto a more coarse grid or onto something like a "conventional" EXAFS grid.

So ... what I recommend, if you want to use Athena (*), is that you find some way to rebin your data onto a grid that fits within the 8192 limit. Athena's rebinning tool uses a simple box car average -- that would suit your data just fine.

If you don't know what a box car average is, a google search for "box car average excel", "box car average matlab", "box car average python", etc... should provide a hint. Once you do that, Athena should behave without surprises.

B

(*) Or use Athena with Larch. Larch does not have the 8192 limit. But you should still process the data onto a sensible grid.

B


--
 Bruce Ravel  ------------------------------------ bra...@bnl.gov

 National Institute of Standards and Technology
 Synchrotron Science Group at NSLS-II
 Building 743, Room 114
 Upton NY, 11973

 Homepage:    http://bruceravel.github.io/home/
 Software:    https://github.com/bruceravel
 Demeter:     http://bruceravel.github.io/demeter/
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