Re: scientific computing with ocaml, gsl api

From: David McClain (dmcclain@azstarnet.com)
Date: Wed Mar 29 2000 - 09:13:47 MET DST

  • Next message: David McClain: "Re: scientific computing with ocaml, gsl api"

    Julian,

    I'm not quite sure what you mean by Euclidean N-dimensional algebra, but NML
    does already support inner and outer products of N-dimensional objects.
    There are also Matrix routines for SVD, Cholesky decomposition, and LU
    decomposition, inversion, and determinants, etc...

    In fact one of the things I do quite frequently is a DFT demodulation of
    image stacks obtained with a chopped sensor. Hence to multiply and sum the
    image planes with a twiddle vector I simply do:

        images <*> twiddles

    and voila, the result is a single image that represents the sum of
    individual weighted images. The "images" vector above is a 3-dimensional
    stack of 2-D image planes, while the "twiddles" is a simple vector of scalar
    (complex) weights. The "<*>" is shorthand for my inner-product operator.

    I am sure that you will easily represent your force problem in the
    vectorized domain of NML!

    - DM

    ----- Original Message -----
    From: Julian Assange <proff@iq.org>
    To: David McClain <dmcclain@azstarnet.com>
    Cc: <caml-list@inria.fr>; <proff@iq.org>
    Sent: Tuesday, March 28, 2000 11:00 PM
    Subject: scientific computing with ocaml, gsl api

    > "David McClain" <dmcclain@azstarnet.com> writes:
    >
    > > Dear OCaml Enthusiasts,
    > >
    > > It has been stewing for more than a year now, a continuing work in
    progress,
    > > but it is high time that I release a matured copy of the code and
    sources to
    > > the world. NML (Not ML, Numeric Modeling Language, Numeric ML, Nearly
    ML,
    > > ...) is an interactive, dynamically typed, tail pure, compiled (to
    native
    > > code closures) functional language, whose syntax closely follows that of
    > > OCaml, but where all math operations are overloaded and vectorized on
    real
    > > and complex data in the form of lists, vectors, multidimensional arrays,
    > > tuples, etc.
    >
    > This looks very nice david! Is it possible to use the vectorised, array
    support
    > within ocaml? i.e I'm a little leary of using NML for mid-large
    applications due
    > to the lack of type checking, but it does seem to be an excellent language
    for
    > scientific interrogation.
    >
    > Have you looked at the GNU scientific library?
    >
    > http://sourceware.cygnus.com/gsl
    >
    > This is a wonderfully eclectic scientific library in C, with strong
    > control over float properties. An ocaml or MNL binding would be a
    > killer app.
    >
    > > Are there any plans to support euclidian vector algebra in n
    > > dimensions? Preferably with user-defined physical field properties?
    > >
    > > Specifically I want to be able to do things like define two vectors,
    > > v_1, and v_2, have v_1 radiate a force decreasing at 1/distance^2, and
    > > calculate the the force vector across all of v_2. This is more complex
    > > than simple point sources, but there doesn't even seem to be support
    > > for those. It could be argued that a two body case is so trivial it
    > > doesn't need supporting, which is probably true, but n body cases and
    > > non point sources are hard work and useful in many (even non-physics)
    > > applications. i.e the v_1, v2 example I mentioned above forms part of
    > > an optimisation solution I have for laying out 2d chemical labels
    > > (part-of-molecule number, atomic weight, charge, etc) over a 3d
    > > polynucleartide in such a way as to avoid the labels writing accross
    > > each other.
    > >
    > > Cheers,
    > > Julian
    >



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