[Arjen Markus] This page is meant for collecting ideas on how to deal with numerical analysis in Tcl.

'''The rationale'''

There are quite a few attempts to implement numerical analysis methods in Tcl, but so far there is no ''framework'' (conceptual or otherwise) that you can readily use. Everybody tries to do it in his or her own way.

If we look at our Perl and Python colleagues, they have PDL (Perl Data Language) and Numpy (or Numarray it seems to be called nowadays). There is no equivalent to my knowledge in Tcl, though there are quite extensive packages like [la] and [NAP] that might classify as such.

'''The basic problem'''

Numerical methods often deal with collections of data:

   * Arrays (in the C or Fortran sense) of numbers
   * Vectors in an N-dimensional space
   * Matrices (square or rectangular)
   * Higher-dimensional structures (but these tend to be used mainly in specialised areas)

One could think of nested lists (see [Playing APL] for an example) to represent them, but the [la] package uses plain lists for good reasons:

   * More efficient
   * The possibility to represent row and column vectors, important for a linear algebra package

Standard libraries exist in both C and Fortran for many problems (think of: Lapack and FFT libraries for instance). We can access these via small wrappers, generated via SWIG or Critcl and in fact a few such wrappers already exist.

'''The solution?'''

We should decide what the best methods are for dealing with numerical data and create an easy to use framework out of this. The design issues are:

   * Comfortable use from within Tcl 
   * Acceptable performance, even with large sets of data
   * Easy to pass to and from binary extensions

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