-----Original Message----- From: ifeffit-bounces@millenia.cars.aps.anl.gov [mailto:ifeffit- bounces@millenia.cars.aps.anl.gov] On Behalf Of Christopher Allen Sent: Wednesday, August 26, 2009 12:33 PM To: XAFS Analysis using Ifeffit Cc: ifeffit@millenia.cars.aps.anl.gov Subject: [Ifeffit] Athena error reading file

Hi everyone,

I have two scans taken at x19a of the NSLS (attached) recently that won't open in Athena. Scans before and after these two had no

I believe the problem is a comment line that contains a single number. If you remove that line, they read in just fine. Shelly problem,

but these give the error reading file message. This was true using whatever version of Athena is on their beamline computer and also version 0.8.056.

Thank you in advance,

Chris

---------------------------- Chris Allen Northeastern University for Renewable Energy Technology 317 Egan Research Center 360 Huntington Avenue Boston, Ma 02115 617-373-5630

On Wednesday 26 August 2009 01:33:16 pm Christopher Allen wrote:

Hi everyone,

I have two scans taken at x19a of the NSLS (attached) recently that won't open in Athena. Scans before and after these two had no problem, but these give the error reading file message. This was true using whatever version of Athena is on their beamline computer and also version 0.8.056.

Chris, Shelly and Carlo both gave good advice. I'll offer a bit more, this more specific to the situation of collecting data at NSLS. Most (but not all) of the XAS beamlines at NSLS use the XDAC program for data collection. XDAC allows you to enter a few lines of comments describing a scan or set of scans. These comment lines are written to the data file just above the line of dashes. Athena uses Ifeffit to import data from column data files. Ifeffit uses some heuristics to try to figure out what part of the file is the header and what part is the columns of data. Matt did a fairly amazing job -- Ifeffit gets that question right surprisingly often. However, one situation that will always fool Ifeffit is when a line among the headers looks like data. In the context of Ifeffit, "looking like data" means a line that has only numbers with no non-numeric characters. The upshot of this is that giving XDAC a comment like "3.71", while probably meaningful to you, is guaranteed to make Ifeffit (and Athena) unhappy. Because XDAC writes out its headers without any beginning-of-line character, instead relying on the line of dashes to mark the boundary between header and data, an XDAC comment consisting only of numeric characters will always trigger this problem. Fortunately, the solution is trivial: be more verbose in the XDAC comment box. HTH, B -- Bruce Ravel ------------------------------------ bravel@bnl.gov National Institute of Standards and Technology Synchrotron Methods Group at NSLS --- Beamlines U7A, X24A, X23A2 Building 535A Upton NY, 11973 My homepage: http://xafs.org/BruceRavel EXAFS software: http://cars9.uchicago.edu/~ravel/software/exafs/