% @(#)regresrobu.hlq	17.1.1.1 (ESO-IPG) 01/25/02 17:43:53
%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
%.COPYRIGHT  (c)  1993 European Southern Observatory
%.IDENT      regresrobu.hlq
%.AUTHOR     PB, IPG/ESO
%.KEYWORDS   MIDAS, help files, 
%.PURPOSE    On-line help file for the command: REGRESSION/ROBUST
%.VERSION    1.0  22-MAR-95 : Creation, PB
%----------------------------------------------------------------
\se
SECTION./ROBUST
\es\co
REGRESSION/ROBUST				      22-MAR-95  PB
\oc\su
REGRESSION/ROBUST  tab y  x1[,x2,..,xn] [file] [out_col] [res_col]
	Robust multi-variate regression by Least Median of Squares
\us\pu
Purpose:    
            This commands performs a robust  multi-variate regression 
            by Least Median of Squares, using the PROGRESS algorithm
            (Rousseuw, 1987).
 \\
\up\sy
Syntax:     
            REGRES/ROBUST tab y x1[,x2,..,xn] [file] [out_col] [res_col] [con]
 \\
\ys\pa
            tab      = Table name 
 \\
\ap\pa
            y        = Column containing the dependent variable
 \\
\ap\pa
            x1,x2..  = Columns containing the independent variables. 
 \\
\ap\pa
            file     = Name of the ASCII file containing information 
                       on the different steps of the regression.
                       (Default: progress.out).
 \\
\ap\pa 
            out_col  = Column containing the robustly estimated values
                       This column will be created if it does not exist
                       (Default :WCALC)
 \\
\ap\pa 
            res_col  = Column containing the residuals. This column will 
                       be created if it does not exist (Default :RESIDUAL).
 \\
\ap\pa
            con    = Constant term, Y or N. Default is Y, constant term
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\ap\sa
See also: 
            REGRESS/POLY, REGRESS/LINEAR
\as\no
Note:       
            None, but for more information, read the book: \\
            "Robust regression and outliers rejection",  \\
            Wiley and Sons, New-York, 1987.

            Output is stored in the following keywords:
            OUTPUTR(1) - slope
            OUTPUTR(2) - zero point	    
            	         if con = N, OUTPUTR(2) = 0. 
            OUTPUTR(3) - error of OUTPUTR(1)
            OUTPUTR(4) - error of OUTPUTR(2)	    		 
 \\
\on\exs
Examples:
\ex
            REGRESSION/ROBUST  {LINTAB} :AUX :ORDER,:X,:X2 ? :AUX 
\xe \sxe