[Ifeffit] Re: Ifeffit Digest, Vol 22, Issue 1

[SCHLEGEL Michel 177447]

> > But: I'm not aware of any beamline saving data in mono steps.
> > AFAIK, only the old Lytle data is in this format.  We should not
> > do anything to encourage this very bad practice. For the record,
> > it's bad because it assumes you know:  1) steps per degree, 2)
> > value of steps at angle=0, and 3) lattice spacing of crystal.  If
> > you don't know all three values, you have nothing.
> > 
> > So, I agree it would be foolish to try to support every beamline
> > format, and not likely to be successful.  I also think putting in
> > the lattice constant for YB66 or polynomial coefficients for the
> > thermal expansion curve of Si is a similarly doomed.
> > 
> 
> I think that Matt is right.
> 
> It is a shame to waste the old Lytle data, but let us not 
> allow that to continue.  If someone really wants the data 
> from that old Lytle data bank then there are inconvenient
> ways to extract the information, just as it should be.

Would it be advisable - realistic to convert once and for all
the old Lytle data from the mono step scale to the energy scale?
(I mean, by wirtue of a well-hacked perl macro).  Is there any 
scientific reason why the old  mono step scale should be kept?

> I second the "Athena test".

As such, spec files with all scans cannot be read by Athena, but 
you can copy out individual "scans" in separate files, for which 
comment lines all start with  "#", the last line given the name 
of the motors and detectors ("energy", "IO"...) and the data is 
then ordered as an array. The promblems are (1) usually all scans 
(table, slits...) are collected in one file, and (2) the column 
ordering varies from file to file (a problem which is already 
wonderfully addressed by Athena, though). 
So maybe a separate splitting macro to take out the do the job 
would be more convenient than asking athena to do all theis work.
Granted it's tedious, but compared to the time needed to correctly 
extract, interpret & fit the data...

Michel