[Ifeffit] Some thoughts on gifeffit

Matt Newville newville at cars.uchicago.edu
Mon Mar 11 09:35:03 CST 2002

Hi Paul,

Thanks for all the comments and kind words!

> 1. It would be nice to have legends on the pgplot window --
> colors are nice but if one is comparing different data sets,
> it is really hard to tell them apart (especially if the page
> is printed).  Also one of the things I used to do with the
> unix environment was to set up a series of different autobak
> files with different rback settings so I could see the effect
> of moving the fit window.  It was nice to be able to compare
> all of these in the same graphic window -- it doesn't seem
> like this can be done anymore (am I right about this?)

Both excellent suggestions, and not hard to do.
The 'key' keyword in the plot command will give a
'gnuplot-like' plot legend:
   plot(dat.x, dat.y, key='Data #1')

Using that, a plain-old macro that changes rbkg might look like

   macro try_rbkg  in_group  out_group  1.00
     spline($1.energy, $1.xmu, kweight=1, rbkg=$3, group=$2)
     $2.chik = $2.chi * $2.k^2
     plot($2.k, $2.chik, key=$2)
   end macro

   read_data(my.xmu, group=dat,type=xmu)
   try_rbkg  my   r05  0.5
   try_rbkg  my   r07  0.7
   try_rbkg  my   r09  0.9
   try_rbkg  my   r11  1.1

Making a GUI form to show rbkg from [..] to [..] in steps of
[..] would be simple and useful.  I'll try to get this in the
next version.

> 2. In terms of documentation, a nice intro would be to
> highlight the differences between gifeffit and the more
> traditional unix command line version to help new users get
> up to speed -- again I am willing to write some of this (if
> help is needed), but I still need to get up to speed myself!

OK... yes any suggestions or help writing such documentation
would be greatly appreciated!!

> 3. I am not 100% sure of this, but it seemed that when, for
> example, I had the plotter open and subsequently read in a
> new data set in another window or defined a new array, the
> pop-up menus in the plotter window weren't aware of the new
> data set (at least not immediately).

Yes, this is annoying.  Clicking on a 'dropdown list of groups'
should show the complete list.  Currently it shows the
last-known list and _then_ gets the latest list, so it's easy
to get a step behind.  I'll try to fix it.

> One last thing, on the ifeffit homepage, it is stated that
> feffit is included in the distribution, but is not stable --
> what is unstable and what are the limitations of the feffit
> module within gifeffit currently, e.g. is it something I can
> use to fit data?

The feffit() command within ifeffit is OK (well, as far as I
know!).  The message was about the Feffit Program that is
included with the ifeffit distribution kit.  This is still
based o a fairly different set of source code, though I'm
trying to fully merge the two.  Because of problems with this
merger, there were some serious problems with the Feffit
program.  I think these are worked out now, so that the Feffit
program that installs with ifeffit is now as good as the 'old
feffit program'.


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