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Conference rusure::math

Title:Mathematics at DEC
Moderator:RUSURE::EDP
Created:Mon Feb 03 1986
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2083
Total number of notes:14613

1255.0. "Problem with curve fitting" by OLDTMR::TUCKER () Thu Jun 21 1990 14:42

    
    Hello.  I am working on a curve fitting program in C from a magazine
    article.  The problem is the article left out the algorithms of the
    three routines that solve overdetermined systems of equations.  These
    three norms are the L1-norm, the least squares norm, and the minimax 
    norm.  Does anyone know what books I can find these algorithms in?
    
    Marie  
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1255.1Some algorithms available from ACMALLVAX::JROTHIt's a bush recording...Fri Jun 22 1990 01:0425
    One general reference is "Matrix Computations" by Golub and Van Loan,
    published by Johns Hopkins Press.  For least squares, see "Solving
    Least Squares Problems" by Lawson and Hanson, which has FORTRAN
    routine listings.

    Algorithms for these are available on-line (in FORTRAN...) from
    netlib - in particular see ACM algorithms 544 (weighted least squares
    solutions), 551/552 for L1 solutions of over determined equations
    and 495 for the Chebychev (L_infinity or minimax) norm.

    You can obtain these by sending a message to netlib (at Oak Ridge
    National Labs) of the following form:

	to:	DECWRL::"netlib@ornl.gov"
	subj:	send 544 from toms

	one line message:	send 544 from toms

   You can also ask for "send index from toms" or just "send index" to find
   the other goodies.

   Hope this helps...  you'll find that the least squares case is by far
   the easiest to implement and I'd recommend trying that first.

   - Jim
1255.2Thank youOLDTMR::TUCKERWed Jun 27 1990 15:486
    
    
    Thanks Jim, what you told me was very helpful.
    
    
    Marjorie Marie