% @(#)edit_fit.hlq	19.1 (ESO-IPG) 02/25/03 13:19:16 
%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
%.COPYRIGHT  (c)  1990 European Southern Observatory
%.IDENT      edit_fit.hlq
%.AUTHOR     JDP, IPG/ESO
%.KEYWORDS   MIDAS, help files, EDIT/FIT
%.PURPOSE    On-line help file for the command: EDIT/FIT
%.VERSION    1.0  12-APR-1984 : Creation, JDP
%----------------------------------------------------------------
\se
SECTION./FIT
\es\co
EDIT/FIT						12-APR-1984  JDP
\oc\su
EDIT/FIT  function
	interactive function editor
\us\pu
Purpose:    
            Interactive definition of functions. EDT compatible
            editing operation.
            The command creates and/or edits a structured array of
            functions and corresponding parameters, according to the
            rules defined in the notes below.
\up\sy
Syntax:     
            EDIT/FIT function
\ys\pa
            function = function to be created or modified.
                       If the file function.fit does not exists,
                       it is created by the command.
\ap\no
Note:       The editor is a modified version of the EDT editor in keypad
            mode. The following keypad functions are not implemented :
            OPEN LINE, CHNGCASE, DEL EOL, CHAR, CUT, PASTE and SUBS.
\\
            The following commands are implemented : EXIT and QUIT.
            On-line HELP facility available.
\\
            The editor uses a temporary table to store 
            functions and parameters in two columns.
\\           
            In the column FUNCTIONS the following info is stored:
            function specifications with parameter guesses
            . function specification :
             name(ind_var[,ind_var...];par1[,par2...])
\\
            In the column PARAMETERS the following info is stored:
            . parameter specification :
             par1=value         -- to define value and error
             par1=value[@]      -- to define value with the optional
                                    flag '@' to fix the parameter
             par1=constrain     -- to define parameter constrain
                                     as :
                                     constant*par2,
                                     par2*constant,
                                     par2/constant, or
                                     par2
\\
            A list of the functions supported by the system, and
            the description of the corresponding parameters is available
            in the printed version of the manual. Functions not supported
            by the system can be included with the command CREATE/FUNCTION.
\on\exs
Examples:
\ex
           To fit two gaussians with equal fwhm and a linear background,
           the function edited with this command should look like :
\xe\ex
           POLY(X;A1,A2)                     A1=0.@ A2=2
            -- linear slope
\xe\ex
           GAUSS(X;B,C,D)                    B=10. C=100.  D=4.
            -- first gaussian
\xe\ex
           GAUSS(X;E,F,G)                    E=15. F=120.  G=D
           -- second gaussian
\xe \sxe
