From: isaac@gildor.Physics.McGill.CA (Martin-D. Lacasse)
Newsgroups: sci.math.num-analysis
Subject: C-based fitting and data manipulation program
Date: 17 Nov 92 00:33:01 GMT
Reply-To: isaac@physics.mcgill.ca
Organization: Center for the Physics of Materials, McGill University


    If you use GNUPLOT and do day to day fitting (linear or non-linear)
    or Fourier transforms, column manipulation and plotting (and
    moreover, you hate awk) then this might interest you.

    Hi everyone!

    In course of my (student) work, I had to deal with a *lot* of data
    files to fit, modify, plot, Fourier transform, etc. This lead me
    (over the last year) to write a mathematical front end to GNUPLOT.
    At first, this program was built for a particular personal need,
    but very fast it spreaded in our research group and I soon had to
    answer requests for further developments.

    Basically, the program runs with GNUPLOT (version 3.2 is fine,
    earlier versions need to be recompiled to prevent exit on error)
    without any modification. It allows the user to use the syntax of
    C-shell for having aliases, while and foreach loops, Macros can
    also be defined. This is how I dealt with the multiple files to
    transform/fit/plot. This is particularly useful when one has to fit
    the parameters obtained from a series of previous fits. For the
    data (column) manipulation, the program uses a C-interpreter I
    wrote, with some particular adaptations. It supports variables,
    vectors (the data columns) as well as strings. All vector
    assignments are implicit loops, Thus, commands like:  x=1; X=x++
    define a vector X ranging from 1 to the vector size. Most (if not
    all) C math library functions are available for data manipulation.
    So, commands like Y = sin(X*pi)^2 assigns vector Y to the square of
    the sin() of PI times each element of vector X. With these
    extensions, the resulting flavour of C becomes a nice data
    manipulation language.

    As it stands now, it is only supported on UNIX and compiles
    on AIX, ULTRIX, IRIX, and HPUX.

    It is fully documented, and a series of past applications are
    provided as examples. If you know C and C-shell programming, you'll
    feel at home. If not, you'll find that using it is relatively easy.
    Although the program is still under development, it is in a
    relatively stable state.

    Some of the included mathematical routines were based on the ones
    found in Numerical Recipes. Most of them were deeply modified to
    allow user-defined application, dynamic memory, and elegant error
    recovery. However, before I know more about the fuzzy (and
    sometimes funny) limits of numerical method copyrights I suggest
    that you don't use that program unless you already have access to
    NR routines. If someone can enlighten me about this point, please do!
    (Use e-mail, I don't think this group is the good place for that).

    This program is called FUDGIT and is available by anonymous ftp at
    ftp.physics.mcgill.ca. 

    Enjoy!

---

 Martin-D. Lacasse                   internet: isaac@physics.mcgill.ca
 Physics Department                     voice: (514) 398-7027
 McGill University                        fax: (514) 398-8434
 Montreal
 Quebec, Canada
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