June 26, 1995

	Several new features have been added to the latest update of Specfit,
version 8.0.  The new features focus on making Specfit easier to use and also
give it some extra power.  Hope you find the new capabilities useful.

MAJOR CHANGES TO SPECFIT

1.  Inserting new components into the fit database can now be done while
	in specfit`s interactive mode.  Previously you had to quit and 
	then rerun specfit to add a whole new component.  Deleting 
	components in the interactive mode is also now possible.
2.  A new minimization routine has been added called numrecipe.  Normally this
	function has been found to be both faster and more effective than
	the old marquadt and simplex routines.  It based on the numrecipe
	routines in the iraf libraries (xtools$numrecipes.x).  This is the
	recommended minimization method.
3.  Now when you press ^C while in specfit it will output the current status
	of the fit values to the final fit database file.  Then, as 
	previously, it will exit specfit.  This will also work with some forms 
	of the kill function.  For example typing "kill pid" will save the
	database file before exiting but "kill -9 pid" will exit without 
	saving the database file.   
4.  We think Specfit will now compile on VMS systems. (But how well it works 
	is unknown.)
5.  In the interactive mode you can now specify which components you would
	like to see plotted.  
6.  Four new fitting functions called tauabs, extdrude, ccmext, disk,
	and ffree have been added.  See the specfit help file for more details.
7.  Specfit will now read both imh and hhh files, in addition to the standard
	ascii format.  Specfit will first look to see if a file exists that
	has the exact same filename that you entered.  If that doesn't exist
	it will add the iraf variable imtype to the end of the filename and 
	see if that file exists.
8.  Specfit's memory requirements have been reduced.
9.  A grid-search fitting algorithm has been added.  It can be run in 
	noninteractive mode only, however.  This algorithmn systematically 
	runs through a variety of values for either one or two parameters 
	and then calls one of the other fitting routines like numrecipes or 
	simplex to optimize the remaining free parameters.  It keeps the best
	fit and then outputs the whole grid to the log files. 

NEW TASKS

1.  In addition to the main task, specfit, two others have been added 
	to create a specfit package.  'dbcreate' is an iraf task that 
	simplifies creating a specfit database file.
2.  'dbcheck' will look at your database files and check to see that they
	are formatted correctly, can be read properly by specfit, and
	do not can contain any inconsistencies in the data.

MINOR CHANGES TO SPECFIT

1.  Pressing 'G' in the interactive mode will list the names of the component
	types.
2.  When you insert a new component you will, of course, be asked for the 
	component's parameter values, step sizes, upper bounds, lower bounds,
	and fix/free status.  The default step sizes, lower bounds, and
	upper bounds are calculated by multiplying the relevant parameter by
	x.  By default x = 10 for upper bounds, x = .1 for lower bounds, and
	x = .001 for step sizes.  You can, however,change the x values as they
	are defined in the parameter files.
3.  In Interactive Mode when changing parameter values, the  default is to use
	the old value.  So if you decide you don't want to change the value 
	just press return and the old value will be retained.
4.  In interactive mode when you enter a component number that is more than
	the number of components actually present it will work as if you had
	entered the number of the last component.
5.  A problem with the Simplex algorithm has been fixed which caused it to
	get stuck at a non-minimal value for chi-square.
6.  Several improvements in error reporting have been made.
7.  All user-supplied models ignore lines beginning with '#' in the input 
	files.
8.  Usercont, userline, and userabs figure out which model has the most
	number of points and allocate storage based on that rather than relying
	on the first model to have the most points in it.
9.  Added a new algorithm to calculate Julian dates.  It is more general and 
	should work for any year after 1900.
10.  Changed the command 'e' in interactive mode to output additional 
	information about the fit, not just the chi-square.
11.  Added capability to put comments in the database file that will be 
	outputted in the final database file.  These comments can be placed 
	on the lines that hold the name of the component and the number of 
	parameters to that component.  For example your line could look like

	gaussian3 	4 #This component fits the spectral component...
	
	Note:  You must preface the comment with the '#' symbol.
12.  The output database files now have fixed-width fields for the parameters
	to keep things lined up and make editing a bit easier.
12.  The directory location of the specfit.key file is now entered as
	a parameter and is no longer hard coded into the program.
13.  Several minor bug fixes have been made. 
14.  Specfit can now handle real valued numbers for the sample ranges.
	Previously only integer values were used.  For example, 3500.3-3600.9
	would have previously been interpreted as 3500-3600.  Now it will
	read the full floating point value.  This is useful for high-resolution
	data.

KNOWN DIFFICULTIES/PROBLEMS

1.  The interrupt handler normally outputs telling the user that it has
	saved the final fit values in a database.  Sometimes however you 
	will not see the message but it will output the final fit anyway.

Thanks to

	Knox Long, Harry Ferguson, Van Dixon, and other members of the HUT
	team for suggested improvements;
	Jeff Odom and many HUT team members for beta testing.

Suggestions for more improvements are welcome, but a new release is not expected
until late in 1995.

						-- Jerry Kriss (gak@pha.jhu.edu)
						and
						   John Grimes (reaper@jhu.edu)