    Octave PROJECTS                                          -*- text -*-
    ===============

    Look in the Octave source archive on Savannah for a possibly more
    current copy.  Also, if you start working steadily on a project,
    please let maintainers@octave.org know.  We might have information
    that could help you.  You should also read the Contributing Guidelines
    chapter in the Octave manual.

    This list is not exclusive -- there are many other things that might
    be good projects, but it might instead be something we already have.
    Also, some of the following items may not actually be considered good
    ideas now.  So please check with maintainers@octave.org before you
    start working on some large project.

    ---------
    Numerical:
    ---------

      * Improve logm, and sqrtm.

      * Improve complex mapper functions.  See W. Kahan, ``Branch Cuts for
        Complex Elementary Functions, or Much Ado About Nothing's Sign
        Bit'' (in The State of the Art in Numerical Analysis, eds. Iserles
        and Powell, Clarendon Press, Oxford, 1987) for explicit
        trigonometric formulae.

      * Make functions like gamma() return the right IEEE Inf or NaN
        values for extreme args or other undefined cases.

      * Improve sqp.

      * Fix CollocWt to handle Laguerre polynomials.  Make it easy to
        extend it to other polynomial types.

      * Add optional arguments to colloc so that it's not restricted to
        Legendre polynomials.

      * Fix eig to also be able to solve the generalized eigenvalue
        problem, and to solve for eigenvalues and eigenvectors without
        performing a balancing step first.

      * Move rand, eye, xpow, xdiv, etc., functions to the matrix classes.

      * Use octave_allocator for memory management in Array classes once
        g++ supports static member templates.

      * Improve design of ODE, DAE, classes.

      * Make QR more memory efficient for large matrices when not all the
        columns of Q are required (apparently this is not handled by the
        lapack code yet).

    ---------------
    Sparse Matrices:
    ---------------

      * Improve QR factorization functions, using idea based on CSPARSE
        cs_dmsol.m

      * Implement fourth argument to the sprand and sprandn, and addition
        arguments to sprandsym that the leading brand implements.

      * Sparse logical indexing in idx_vector class so that something like
        "a=sprandn(1e6,1e6,1e-6); a(a<1) = 0" won't cause a memory overflow.

      * Make spalloc (r, c, n) actually create an empty sparse with n
        non-zero elements?  This allows something like

        sm = spalloc (r, c, n)
        for j=1:c
          for i=1:r
            tmp = foo (i,j);
            if (tmp != 0.)
              sm (i,j) = tmp;
            endif
          endfor
        endfor

        actually make sense.  Otherwise the above will cause massive amounts
        of memory reallocation.

        The fact is that this doesn't make sense in any case as the assign
        function makes another copy of the sparse matrix.  So although spalloc
        might easily be made to have the correct behavior, the first assign
        will cause the matrix to be resized!  There seems to be no simple
        way to treat this but a complete rewrite of the sparse assignment
        functions...

      * Other missing Functions
          - symmmd      Superseded by symamd
          - colmmd      Superseded by colamd
          - cholinc
          - bicg        Can this be taken from octave-forge?
          - cgs
          - gmres
          - lsqr
          - minres
          - qmr
          - symmlq

    -------
    Strings:
    -------

      * Improve performance of string functions, particularly for
        searching and replacing.

      * Make find work for strings.

      * Consider making octave_print_internal() print some sort of text
        representation for unprintable characters instead of sending them
        directly to the terminal.  (But don't do this for fprintf!)

      * Consider changing the default value of `string_fill_char' from SPC
        to NUL.

    ----------------
    Other Data Types:
    ----------------

      * Template functions for mixed-type ops.

      * Convert other functions for use with the floating point type
        including quad, dasrt, daspk, etc.

    ------------
    Input/Output:
    ------------

      * Make fread and fwrite work for complex data.  Iostreams based
        versions of these functions would also be nice, and if you are
        working on them, it would be good to support other size
        specifications (integer*2, etc.).

      * Move some pr-output stuff to liboctave.

      * Make the cutoff point for changing to packed storage a
        user-preference variable with default value 8192.

      * Complain if there is not enough disk space available (I think
        there is simply not enough error checking in the code that handles
        writing data).

      * Make it possible to tie arbitrary input and output streams
        together, similar to the way iostreams can be tied together.

    -----------
    Interpreter:
    -----------

      * Allow customization of the debug prompt.

      * Fix the parser so that

          if (expr) 'this is a string' end

        is parsed as IF expr STRING END.

      * Clean up functions in input.cc that handle user input (there
        currently seems to be some unnecessary duplication of code and it
        seems overly complex).

      * Consider allowing an arbitrary property list to be attached to any
        variable.  This could be a more general way to handle the help
        string that can currently be added with `document'.

      * Allow more command line options to be accessible as built-in
        variables (--echo-commands, etc.).

      * Make the interpreter run faster.

      * Allow arbitrary lower bounds for array indexing.

      * Improve performance of recursive function calls.

      * Improve the way ignore_function_time_stamp works to allow
        selecting by individual directories or functions.

      * Add a command-line option to tell Octave to just do syntax
        checking and not execute statements.

      * Clean up symtab and variable stuff.

      * Input stream class for parser files -- must manage buffers for
        flex and context for global variable settings.

      * make parser do more semantic checking, continue after errors when
        compiling functions, etc.

      * Make LEXICAL_ERROR have a value that is the error message for
        parse_error() to print?

      * Add a run-time alias mechanism that would allow things like

          alias fun function_with_a_very_long_name

        so that `function_with_a_very_long_name' could be invoked as
        `fun'.

      * Allow local changes to variables to be written more compactly than
        is currently possible with unwind_protect.  For example,

          function f ()
    	local prefer_column_vectors = something;
    	...
          endfunction

        would be equivalent to

          function f ()
            save_prefer_column_vectors = prefer_column_vectors;
    	unwind_protect
    	  prefer_column_vectors = something;
    	  ...
    	unwind_protect_cleanup
    	  prefer_column_vectors = save_prefer_column_vectors;
    	end_unwind_protect
          endfunction

      * Fix all function files to check for bogus inputs (wrong number or
        types of input arguments, wrong number of output arguments).

      * Handle options for built-in functions more consistently.

      * Too much time is spent allocating and freeing memory.  What can be
        done to improve performance?

      * Error output from Fortran code is ugly.  Something should be done to
        make it look better.

      * It would be nice if output from the Fortran routines could be
        passed through the pager.

      * Attempt to recognize common subexpressions in the parser.

      * Consider making it possible to specify an empty matrix with a
        syntax like [](e1, e2).  Of course at least one of the expressions
        must be zero...

      * Is Matrix::fortran_vec() really necessary?

      * Rewrite whos and the symbol_record_info class.  Write a built-in
        function that gives all the basic information, then write who and
        whos as M-files.

      * On systems that support matherr(), make it possible for users to
        enable the printing of warning messages.

      * Make it possible to mark variables and functions as read-only.

      * Make it possible to write a function that gets a reference to a
        matrix in memory and change one or more elements without
        generating a second copy of the data.

      * Use nanosleep instead of usleep if it is available?  Apparently
        nanosleep is to be preferred over usleep on Solaris systems.

    --------
    Graphics:
    --------

      * Correctly handle case where DISPLAY is unset.  Provide
      --no-window-system or --nodisplay (?) option.  Provide
      --display=DISPLAY option?  How will this work with gnuplot (i.e.,
      how do we know whether gnuplot requires an X display to display
      graphics)?

    -------
    History:
    -------

      * Add an option to allow saving input from script files in the
        history list.

      * The history command should accept two numeric arguments to
        indicate a range of history entries to display, save or read.

      * Avoid writing the history file if the history list has not
        changed.

      * Avoid permission errors if the history file cannot be opened for
        writing.

      * Fix history problems -- core dump if multiple processes are
        writing to the same history file?

    ------------------------------
    Configuration and Installation:
    ------------------------------

      * Split config.h into a part for Octave-specific configuration
      things (this part can be installed) and the generic HAVE_X type of
      configure information that should not be installed.

      * Makefile changes:
          -- eliminate for loops
          -- define shell commands or eliminate them
          -- consolidate targets

      * Make it possible to configure so that installed binaries and
        shared libraries are stripped.

      * Create a docs-only distribution?

    ------------------------------
    Documentation and On-Line Help:
    ------------------------------

      * Document new features.

      * Improve the Texinfo Documentation for the interpreter.  It would
        be useful to have lots more examples, to not have so many forward
        references, and to not have very many simple lists of functions.

      * The docs should mention something about efficiency and that using
        array operations is almost always a good idea for speed.

      * Texinfo documentation for the C++ classes.

      * Make index entries more consistent to improve behavior of `help -i'.

      * Make `help -i' try to find a whole word match first.

      * Clean up help stuff.

      * Demo files.

    -----
    Tests:
    -----

      * Improved set of tests:

          -- Tests for various functions.  Would be nice to have a test file
    	 corresponding to every function.

          -- Tests for element by element operators:
    	   +  -  .*  ./  .\  .^  |  &  <  <=  ==  >=  >  !=  !

          -- Tests for boolean operators:  &&  ||

          -- Tests for other operators:  *  /  \  '  .'

          -- Tests from bug reports.

          -- Tests for indexed assignment.  Need to consider the following:
    	   o fortran-style indexing
    	   o zero-one indexing
    	   o assignment of empty matrix as well as values
    	   o resizing

      * Tests for all internal functions.

    -----------
    Programming:
    -----------

      * C++ namespace for Octave library functions.

      * Better error messages for missing operators?

      * Eliminate duplicate enums in pt-exp.cc, pt-const.cc, and ov.cc.

      * Handle octave_print_internal() stuff at the liboctave level.  Then
        the octave_value classes could just call on the print() methods
        for the underlying classes.

      * As much as possible, eliminate explicit checks for the types of
        octave_value objects so that user-defined types will automatically
        do the right thing in more cases.

      * Only include config.h in files that actually need it, instead of
        including it in every .cc file.  Unfortunately, this might not be
        so easy to figure out.

      * GNU coding standards:

        -- Add a `Makefile' target to the Makefiles.
        -- Comments on #else and #endif preprocessor commands.
        -- Change error message format to match standards everywhere.

      * Eliminate more global variables.

      * Move procstream to liboctave.

      * Use references and classes in more places.

      * Share more code among the various *_options functions.

    -------------
    Miscellaneous:
    -------------

      * Implement some functions for interprocess communication:  bind,
        accept, connect, gethostbyname, etc.

      * The installation process should also install octave.el.  This
        needs to detect the appropriate Emacs binary to use to
        byte-compile the .el file.  Following GNU Emacs philosophy,
        installation would be into $(prefix)/share/emacs/site-lisp by
        default, but it should be selectable.

      * The ability to transparently handle very large files:

        Juhana K Kouhia  wrote:

          If I have a one-dimensional signal data with the size 400
          Mbytes, then what are my choices to operate with it:

           * I have to split the data
           * Octave has a virtual memory on its own and I don't have to
             worry about the splitting.

          If I split the data, then my easily programmed processing
          programs will become hard to program.

          If possible, I would like to have the virtual memory system in
          Octave i.e., the all big files, the user see as one big array or
          such.  There could be several user selectable models to do the
          virtual memory depending on what kind of data the user have (1d,
          2d) and in what order they are processed (stream or random
          access).

        Perhaps this can be done entirely with a library of M-files.

      * An interface to gdb.

        Michael Smolsky  wrote:

          I was thinking about a tool, which could be very useful for me
          in my numerical simulation work.  It is an interconnection
          between gdb and octave.  We are often managing very large arrays
          of data in our fortran or c codes, which might be studied with
          the help of octave at the algorithm development stages.  Assume
          you're coding, say, wave equation.  And want to debug the
          code.  It would be great to pick some array from the memory of
          the code you're developing, fft it and see the image as a
          log-log plot of the spectral density.  I'm facing similar
          problems now.  To avoid high c-development cost, I develop in
          matlab/octave, and then rewrite into c.  It might be so much
          easier, if I could off-load a c array right from the debugger
          into octave, study it, and, perhaps, change some [many] values
          with a convenient matlab/octave syntax, similar to
          a(:,50:250)=zeros(100,200), and then store it back into the
          memory of my c code.

      * Add a definition to lgrind so that it supports Octave.
        (See http://www.tex.ac.uk/tex-archive/support/lgrind/ for more
        information about lgrind.)

    ------
    Always:
    ------

      * Squash bugs.

    				--30--